Part 3: Analog and Digital Signals in Data Communications

Part 3: Analog and Digital Signals in Data Communications

by | Jan 12, 2022 | Data Communications

Analog and Digital Signals

An analog signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity i.e., analogous to another time varying Signal.

Signals can be analog or digital. Analog signals can have an infinite number of values in a range; digital signals can have only a limited number of values.

Digital to Analog Modulation

Digital-to-analog modulation: the process of changing one of the characteristics of an analog signal based on the information in a digital signal  “Forget me not”: characteristics of a sine wave are amplitude, frequency, phase. Carrier Signal.

  • Sender
    • Produce a high-frequency signal that acts as a basis for the information signal => carrier signal
    • Modulate the carrier signal to reflect the digital information. The information signal is called the modulating signal
  • Receiver
    • Tune in the carrier frequency to receive

Analog to Digital  and Digital  to Analog Communications

  1. Analog Communication :

    In analog communication the data is transferred with the help of analog signal in between transmitter and receiver. Any type of data is transferred in analog signal. Any data is converted into electric form first and after that it is passed through communication channel. Analog communication uses a continuous signal which varies in amplitude, phase, or some other property with time in proportion to that of a variable.

The below figure illustrates the Analog Communication System :

  1. Digital Communication :

    In digital communication digital signal is used rather than analog signal for communication in between the source and destination. They digital signal consists of discrete values rather than continuous values. In digital communication physical transfer of data occurs in the form of digital bit stream i.e 0 or 1 over a point-to-point or point-to-multipoint transmission medium. In digital communication the digital transmission data can be broken into packets as discrete messages which is not allowed in analog communication.

The below figure illustrates the Digital Communication System :

Difference between Analog Communication and Digital Communication :

S .No.          ANALOG COMMUNICATION             DIGITAL COMMUNICATION
01. In analog communication analog signal is used for information transmission. In digital communication digital signal is used for information transmission.
02. Analog communication uses analog signal whose amplitude varies continuously with time from 0 to 100. Digital communication uses digital signal whose amplitude is of two levels either Low i.e., 0 or either High i.e., 1.
03. It gets affected by noise highly during transmission through communication channel. It gets affected by noise less during transmission through communication channel.
04. In analog communication only limited number of channels can be broadcasted simultaneously. It can broadcast large number of channels simultaneously.
05. In analog communication error Probability is high. In digital communication error Probability is low.
06. In analog communication noise immunity is poor. In digital communication noise immunity is good.
07. In analog communication coding is not possible. In digital communication coding is possible. Different coding techniques can be used to detect and correct errors.
08. Separating out noise and signal in analog communication is not possible. Separating out noise and signal in digital communication is possible.
09. Analog communication system is having complex hardware and less flexible. Digital communication system is having less complex hardware and more flexible.
10. In analog communication for multiplexing

Frequency Division Multiplexing (FDM) is used.

 

 In Digital communication for multiplexing

Time Division Multiplexing (TDM) is used.

 
11. Analog communication system is low cost. Digital communication system is high cost.
12. It requires low bandwidth. It requires high bandwidth.
13. Power consumption is high. Power consumption is low.
14. It is less portable. Portability is high.
15. No privacy or privacy is less so not highly secured. Privacy is high so it is highly secured.
16. Not assures an accurate data transmission. It assures a more accurate data transmission.
17. Synchronization problem. Synchronization problem is easier.

 

Bit Rate vs. Baud Rate

Bit rate is the number of bits per second

  • More important in speaking of computer efficiency

Baud rate is the number of signal units per second that are required to represent those bits

  • More important in speaking of data transmission

Determine the bandwidth required to send the signal

Analogy in transportation: a baud is analogous to a car while a bit is analogous to a passenger (1: male, 0: female). The number of cars determines the traffic; that of passengers does not.

Baud Rate Example

An analog signal carries 4 bits in each signal unit. If 1000 signal units are sent per second, find the baud rate and the bit rate

Baud rate = 1000 bauds per second (baud/s)

Bit rate = 1000 x 4 = 4000 bps

The bit rate of a signal is 3000. If each signal unit carries 6 bits, what is the baud rate?

Baud rate = 3000 / 6 = 500 baud/s

Digital-Analog Modulation Schemes

Quadrature shift modulation

All a,f,p changes combined

Amplitude Shift Keying (ASK)

ask

     Peak amplitude during each bit duration is constant

  • Disadvantage
    • Highly susceptible to noise interference because ASK relies on amplitude to differentiate between 1 and 0
    • Need a great gap between amplitude values so that noise can be detected and removed
  • OOK (on/off keying)
    • A popular ASK technique
    • Zero voltage represent a bit value (e.g., 0)
    • Save energy in transmitting information
  • On voice-grade line, up to 1200bps
  • Used to transmit digital data over optical fiber

 

Frequency Shift Keying (FSK)

Only frequency is varied to represent binary 1 or 0

fsk

FSK vs. ASK

  • FSK
    • Less susceptible to error
    • On voice-grade lines, up to 1200bps
    • Commonly used for high-freq (3-30 Mhz) radio

–     Also used at even high freq on LANs that use coaxial cable

Phase Shift Keying (PSK)

  •        Only phase is varied to represent 1 or 0

  •          2-PSK: only 2 phase values are used, each for 1 or 0

4-PSK

Note: PSK is no susceptible to the noise degradation that affects ASK or to the bandwidth limitations of FSK

Modulation device is not able to distinguish small differences in phase => limit BitRate

Why not combine PSK and ASK: x variations in phase with y variations in amplitude result in xy variations => increase bit rate

8-QAM

Quadrature amplitude modulation can be used with a variety of different formats: 8QAM, 16QAM, 64QAM, 128QAM, 256QAM, but there are performance differences and trade-offs
QAM, quadrature amplitude modulation provides some significant benefits for data transmission. As 16QAM transitions to 64QAM, 64QAM to 256 QAM and so forth, higher data rates can be achieved, but at the cost of the noise margin.

Many data transmission systems migrate between the different orders of QAM, 16QAM, 32QAM, etc., dependent upon the link conditions. If there is a good margin, higher orders of QAM can be used to gain a faster data rate, but if the link deteriorates, lower orders are used to preserve the noise margin and ensure that a low bit error rate is preserved.
Accordingly there is a balance to be made between the data rate and QAM modulation order, power and the acceptable bit error rate. Whilst further error correction can be introduced to mitigate any deterioration in link quality, this will also decrease the data throughput.

The diagrams below show constellation diagrams for a variety of formats of modulation:

QAM formats and applications

For some systems the order of the modulation format is fixed, but in others where there is a two way link, it is possible to adapt the order of the modulation to obtain the best throughput for the given link conditions. The level of error correction used is also altered. In this way, changing the modulation order, and the error correction, the data speed can be optimised whilst maintaining the required error rate.

For domestic broadcast applications for example, 64 QAM and 256 QAM are often used in digital cable television and cable modem applications. The order of the QAM modulation has to be set at the transmitter, because the transmission is only one way, and in addition to this, there are thousands of receivers, making it impossible to have a dynamically adaptive form of modulation.

Constellation diagrams for QAM

The constellation diagrams show the different positions for the states within different forms of QAM, quadrature amplitude modulation. As the order of the modulation increases, so does the number of points on the QAM constellation diagram.

Compare among ASK , PSK & FSK .

Parameters ASK FSK PSK
Variable characteristics Amplitude Frequency Phase
Bandwidth Is proportional to signal rate (B =(1+d)S),d is due to modulation & filtering ,lies between 0 & 1. B=(1+d)×S+2Δf B=(1+d)×S
Noise immunity low High High
Complexity Simple Moderately complex Very complex
Error probability High Low Low
Performance in presence of noise Poor Better than ASK Better than FSK
Bit rate Suitable up to 100 bits/sec Suitable upto about 1200 bits/sec Suitable for high bit rates
Part 1: Introduction to Computer Architecture

Part 1: Introduction to Computer Architecture

by | Jan 7, 2022 | Computer Architecture

Introduction to Computer Architecture

  • Computer architecture refers to those attributes of a system visible to a programmer or those attributes that have a direct impact on the logical execution of a program.
  • Computer organization refers to the operational units and their interconnections that realize the architectural specifications.
  • Examples of architectural attributes: Instruction set, the number of bits used to represent various data types (e.g., numbers, characters), I/O mechanisms, and techniques for addressing memory.
  • Example of organizational attributes: Hardware details transparent to the programmer, such as control signals; interfaces between the computer and peripherals; and the memory technology used.
  • For example, it is an architectural design issue whether a computer will have a multiply instruction.
  • On the other hand, it is an organizational issue whether that instruction will be implemented by a special multiply unit or by a mechanism that makes repeated use of the add unit of the system.

 

STRUCTURE AND FUNCTION

  • A computer is a complex system
  • The hierarchical nature of complex systems is essential to both their design and their description
  • The designer need only deal with a particular level of the system at a time
  • At each level, the system consists of a set of components and their interrelationships and the designer is concerned with associated structure and function:
    • Structure: The way in which the components are interrelated
    • Function: The operation of each individual component as part of the structure

Functional View of a Computer

operation

Functional units

  • In general terms, there are only four functional units:
  • Data processing: The computer must be able to process data

– The data may take a wide variety of forms, and the range of processing requirements is broad

  • Data storage: It is also essential that a computer store data.
    • If the computer is processing data on the fly (i.e., data come in and get processed, and the results go out immediately), the computer must temporarily store at least those pieces of data that are being worked on at any given moment o Thus, there is at least a short-term data storage function
    • Equally important, the computer performs a long-term data storage function also
    • Files of data are stored on the computer for subsequent retrieval and update
  • Data movement: The computer must be able to move data between itself and the outside world
    • The computer’s operating environment consists of devices that serve as either sources or destinations of data
    • When data are received from or delivered to a device that is directly connected to the computer, the process is known as input–output(I/O), and the device is referred to as a peripheral
    • When data are moved over longer distances, to or from a remote device, the process is known as data communications
  • Control: There must be control of these three functions
  • This control is exercised by the individual(s) who provides the computer with instructions
  • Within the computer, a control unit manages the computer’s resources and orchestrates the performance of its functional parts in response to those instructions

Possible Operations        

  • The computer can function as a data movement device (Figure 1), simply transferring data from one peripheral or communications line to another
  • It can also function as a data storage device (Figure 2), with data transferred from the external environment to computer storage (read) and vice versa (write)
  • The final two diagrams show operations involving data processing, on data either in storage (Figure 3) or enroute between storage and the external environment (Figure 4)

 

THE THREE CATEGORIES OF COMPUTER ARCHITECTURE

There are three categories of computer architecture, and all work together to make a machine function.

SYSTEM DESIGN

System design includes all hardware parts of a computer, including data processors, multiprocessors, memory controllers, and direct memory access. It also includes the graphics processing unit (GPU). This part is the physical computer system.

INSTRUCTION SET ARCHITECTURE (ISA)

This includes the functions and capabilities of the central processing unit (CPU). It is the embedded programming language and defines what programming it can perform or process. This part is the software that makes the computer run, such as operating systems like Windows on a PC or iOS on an Apple iPhone, and includes data formats and the programmed instruction set.

MICROARCHITECTURE

Microarchitecture is also known as computer organization and defines the data processing and storage element and how they should be implemented into the ISA. It is the hardware implementation of how an ISA is implemented in a particular processor.

THE EVOLUTION OF PROCESSORS

Complex Instruction Set Computer (CISC) and Reduced Instruction Set Computer (RISC) are the two major approaches to processor architecture. CISC processors have a single processing unit, external memory, and a small register set with hundreds of different instructions. These processors have a single instruction to perform a task, and have the advantage of making the job of the programmer easier, as fewer lines of code are needed to get the job done. This approach uses less memory, but can take longer to complete instructions.

The RISC architecture was the result of a rethink, which has led to the development of high-performance processors. The hardware is kept as simple and fast as possible, and complex instructions can be performed with simpler instructions.

Microprocessors are digital systems which read and execute machine language instructions. Instructions are represented in a symbolic format called an assembly language. These are processors which are implemented on a single, integrated circuit. Common microprocessors used today are the Intel Pentium series, IBM PowerPC, and the Sun SPARC, among others. Nearly all modern processors are microprocessors, which are often available as standard on von Neumann machines.

THE PROS AND CONS OF THE VON NEUMANN ARCHITECTURE

There are a number of reasons why the von Neumann architecture has proven to be so successful. It is relatively easy to implement in hardware, and von Neumann machines are deterministic and introspectable. They can be described mathematically and every step of their computing process is understood. You can also rely on them to always generate the same output on one set of inputs.

The biggest challenge with von Neumann machines is that they can be difficult to code. This has led to the growth of computer programming, which takes real-world problems and explains them to von Neumann machines.

When a software program is being written, an algorithm is reduced to the formal instructions that a von Neumann machine can follow. However, the challenge is that not all algorithms and problems are easy to reduce, leaving unsolved problems.

Part 3: Analog and Digital Signals in Data Communications

Part 2: Data Communication – Network Models

by | Jan 6, 2022 | Data Communications

Networking

  • Network

A network is a set of devices (often referred to as nodes) connected by links. A node can be a computer, printer, or any other device capable of sending and/or receiving data generated by other nodes  on the network.

  • Network criteria
    • Performance
    • reliability

–     security

Point-to-Point Connection

A point-to-point line configuration provides a dedicated link between two devices. The entire capacity of the channel is reserved for transmission between those two devices.

Multi-point Connection

A multipoint line configuration is one in which more than two specific devices share  a single link. In a multipoint environment, the capacity of the channel is shared, either spatially or temporally.

multi conn

Physical Topologies

The    topology of a network is the geometric representation of the relationship of all links and linking devices to one other. Two or more devices connect to a link; two or more links form a topology.

Mesh Topology

In a mesh topology, every device has a dedicated point-to-point link to every other device. The term dedicated means that the link carries traffic only between the two devices it connects.

mesh

Advantages

  • The use of a dedicated links guarantees that each connection can carry its own load, thus eliminating the traffic problems that can occur when links must be shared by multiple devices.
  • A mesh topology is robust. If one link becomes unusable, it does not incapacitate the entire system.
  • When every message sent travels along a dedicated link, only the intended recipient sees it.

Physical boundaries  prevent other users from gaining access to messages.

  • Point-to Point links make fault identification and fault isolation

Disadvantages

  • A big amount of cabling and a big number of I/O ports required, i.e,  the hardware required can be very expensive.
  • Because every device must be connected to every other device, installation and reconfiguration are difficult.
  • For these reasons a mesh topology is usually implemented in a limited fashion.
  • For example, as a backbone connecting the main computers to a hybrid network that can include several other topologies.

Star Topology

In a star topology, each device has a dedicated point-to-point link only to a central controller, usually called a hub. A star topology does not allow direct traffic between devices. If one device wants to send data to another, it sends the data to the controller, which  then relays the data to the other connected device.

Advantages

  • It is easy to install and reconfigure
  • The star topology is robust. If one link fails, only that link is affected. This factor also lends itself to easy fault identification and fault isolation.

Disadvantages

  • A big amount of cabling and a big number of I/O ports required, i.e,  the hardware required can be very expensive.

Note: Star topology requires far less cable than  Mesh topology.

Bus Topology

In a bus topology  one long cable acts as a backbone to link all the devices in the network. Nodes are  connected to the bus cable by drop lines and taps. A drop line is  a connection running between the device and the main cable. A tap is a connector that either splices into the main cable or punctures the sheathing of a cable to create a contact with the metallic core.

bus

Advantages

  • Easy to install
  • Bus topology uses less cabling than mesh, star, or tree topologies.

Disadvantages

  • Difficult reconfiguration and fault isolation. A bus is usually designed to be optimally efficient at installation. It can therefore be difficult to add a new devices.
  • A fault or break in the bus cable stops all transmission, even between devices on the same side of the problem. The damaged area reflects signals back in the direction of origin, creating noise in both directions.

Ring Topology

In a ring topology, each device has a dedicated point-to-point line configuration only with the two devices on either side of it.

ring

Advantages

  • Easy to install and reconfigure. To add or delete a device require only two connections.
  • Easy fault isolation

Disadvantages

  • A break in the ring (such as a disabled station) can disable the entire network. Categories of Networks

Category Of Networks

Local Area Networks

A Local Area Network (LAN) is a private network that connects computers and devices within a limited area like a residence, an office, a building or a campus. On a small scale, LANs are used to connect personal computers to printers.

Metropolitan Area Networks

A Metropolitan Area Network (MAN) is a larger network than LAN. It often covers multiple cities or towns. It is quiet expensive and a single organization may not have own it.

Wide Area Networks

A Wide Area Network (WAN) is a much larger network than LAN and MAN. It often covers multiple contries or contenants. It is quiet expensive and a single organization may not have own it. Satellite is used to manage WAN.

Following are the important differences between LAN, MAN and WAN.

Sr. No. Key LAN MAN WAN
1 Definition LAN stands for Local Area Network. MAN stands for Metropolitan Area Network. WAN stands for Wide Area Network.
2 Ownership LAN is often owned by private organizations. MAN ownership can be private or public. WAN ownership can be private or public.
3 Speed LAN speed is quiet high. MAN speed is average. WAN speed is lower than that of LAN.
4 Delay Network Propagation Delay is short in LAN. Network Propagation Delay is moderate in MAN. Network Propagation Delay is longer in WAN.
5 Congestion LAN has low congestion as compared to WAN. MAN has higher congestion than LAN. WAN has higher congestion than both MAN and LAN.
6 Fault Tolerance Fault Tolerance of LAN is higher than WAN. Fault Tolerance of MAN is lower than LAN. Fault Tolerance of WAN is lower than both LAN and MAN.
7 Maintenance Designing and maintaining LAN is easy and less costly than WAN. Designing and maintaining WAN is complex and more costly than LAN. Designing and maintaining WAN is complex and more costly than both LAN and MAN.

Network Models

Sending a Letter

Internet Model

The TCP/IP model, sometimes referred to as a protocol stack, can be considered a condensed version of the OSI model.

Internet uses TCP/IP protocol suite, also known as Internet suite. This defines Internet Model which contains four layered architecture. OSI Model is general communication model but Internet Model is what the internet uses for all its communication. The internet is independent of its underlying network architecture so is its Model. This model has the following layers:

  • Application Layer: This layer defines the protocol which enables user to interact with the network. For example, FTP, HTTP etc.
  • Transport Layer: This layer defines how data should flow between hosts. Major protocol at this layer is Transmission Control Protocol (TCP). This layer ensures data delivered between hosts is in-order and is responsible for end-to-end delivery.
  • Internet Layer: Internet Protocol (IP) works on this layer. This layer facilitates host addressing and recognition. This layer defines routing.
  • Link Layer: This layer provides mechanism of sending and receiving actual data. Unlike its OSI Model counterpart, this layer is independent of underlying network architecture and hardware.

Peer to Peer Process

p2p

 

Physical Layer

physical

The lowest layer of the OSI Model is concerned with electrically or optically transmitting raw unstructured data bits across the network from the physical layer of the sending device to the physical layer of the receiving device. It can include specifications such as voltages, pin layout, cabling, and radio frequencies. At the physical layer, one might find “physical” resources such as network hubs, cabling, repeaters, network adapters or modems.

Data Link Layer

Data link

At the data link layer, directly connected nodes are used to perform node-to-node data transfer where data is packaged into frames. The data link layer also corrects errors that may have occurred at the physical layer.

The data link layer encompasses two sub-layers of its own. The first, media access control (MAC), provides flow control and multiplexing for device transmissions over a network. The second, the logical link control (LLC), provides flow and error control over the physical medium as well as identifies line protocols.

Protect Your Network Layers with Forcepoint NGFW

Data link

Network Layer

network

The network layer is responsible for receiving frames from the data link layer, and delivering them to their intended destinations among based on the addresses contained inside the frame. The network layer finds the destination by using logical addresses, such as IP (internet protocol). At this layer, routers are a crucial component used to quite literally route information where it needs to go between networks.

Transport Layer

transport

The transport layer manages the delivery and error checking of data packets. It regulates the size, sequencing, and ultimately the transfer of data between systems and hosts. One of the most common examples of the transport layer is TCP or the Transmission Control Protocol.

Application Layer

application

At this layer, both the end user and the application layer interact directly with the software application. This layer sees network services provided to end-user applications such as a web browser or Office 365. The application layer identifies communication partners, resource availability, and synchronizes communication.

Example

A node with physical address 10 sends a frame to a node with physical address 87. The two nodes are connected by a link. At the data link level this frame contains physical addresses in the header. These are the only addresses needed. The rest of the header contains other information needed at this level. The trailer usually contains extra bits needed for error

The Open Systems Interconnection(OSI) Model Defined

The OSI Model (Open Systems Interconnection Model) is a conceptual framework used to describe the functions of a networking system. The OSI model characterizes computing functions into a universal set of rules and requirements in order to support interoperability between different products and software. In the OSI reference model, the communications between a computing system are split into seven different abstraction layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

Created at a time when network computing was in its infancy, the OSI was published in 1984 by the International Organization for Standardization (ISO). This model has seven layers:

  • Application Layer: This layer is responsible for providing interface to the application user. This layer encompasses protocols which directly interact with the user.
  • Presentation Layer: This layer defines how data in the native format of remote host should be presented in the native format of host.
  • Session Layer: This layer maintains sessions between remote hosts. For example, once user/password authentication is done, the remote host maintains this session for a while and does not ask for authentication again in that time span.
  • Transport Layer: This layer is responsible for end-to-end delivery between hosts.
  • Network Layer: This layer is responsible for address assignment and uniquely addressing hosts in a network.
  • Data Link Layer: This layer is responsible for reading and writing data from and onto the line. Link errors are detected at this layer.
  • Physical Layer: This layer defines the hardware, cabling wiring, power output, pulse rate etc.

Bit-to-Signal Transformation

To be transmitted, data must be transformed to electromagnetic signals.

Bit-Rate Control

  • The transmission medium provides the upper limit on data rate, the physical layer controls it Bit Synchronization
  • The physical layer provides clocking mechanisms to control the timing of bit transfer Multiplexing
  • A physical link may need to be divided into logical channels, each used by a transmission, for better efficiency

Circuit Switching

Allowing pairs of nodes to have their dedicated links is a function of the physical layer Signals

  • The main function of the physical layer is moving information in the form of electromagnetic signals across a transmission media.
  • Information can be in the form of data, voice, picture, and so on.
  • Generally the information usable to a person or application  is not in a form that can be transmitted over a network.
  • Data stream of 1s and 0s must be turned into energy in the form of electromagnetic signals.
Part 3: Analog and Digital Signals in Data Communications

Part 1: Introduction to Data Communications

by | Jan 6, 2022 | Data Communications

Data Communications

Data Communications :  Data Communication is the exchange of data (in the form of 0’s and 1’s) between two devices via some form of transmission  medium (such  a cable).

In other way can define, Data Communication is a process of exchanging data or information. In case of computer networks this exchange is done between two devices over a transmission medium. This process involves a communication system which is made up of hardware and software. The hardware part involves the sender and receiver devices and the intermediate devices through which the data passes. The software part involves certain rules which specify what is to be communicated, how it is to be communicated and when. It is also called as a Protocol. The following sections describes the fundamental characteristics that are important for the effective working of data communication process and is followed by the components that make up a data communications system.

What is important?

    • Delivery (deliver data to the correct destination)
    • Accuracy (must deliver the data accurately, no altered data in transmission)

Timeliness (deliver data in timely manner, data delivered late are useless)

Aspects of Data Communications

  • Components
  • Data representation
  • Direction of data flow

 

Components of a Communication System

  • Message:

    The message is the information (or data) to be transmitted. For example, text, numbers, pictures, sound, video, or any combination of these.

  • Sender:

    sender is the device that sends the data message. It can be a computer, telephone, video camera, and so on.

  • Receiver:

    The receiver is the device that receives the message.

  • Medium (Channel): The transmission medium is the physical path by which a message travels from the sender to receiver. For example twisted pair wire, coaxial cable, fiber-optic cable, radio waves (terrestrial or satellite microwaves).
  • Protocol:

    A protocol is a set of rules that govern data communication. It represents an agreement between the communicating devices.

Characteristics of Data Communication

The effectiveness of any data communications system depends upon the following four fundamental characteristics:

1. Delivery:

data should be delivered to the correct destination and correct user.

2. Accuracy:

The communication system should deliver the data accurately, without introducing any errors. The data may get corrupted during transmission affecting the accuracy of the delivered data.

3. Timeliness:

Audio and Video data has to be delivered in a timely manner without any delay; such a data delivery is called real time transmission of data.

4. Jitter:

It is the variation in the packet arrival time. Uneven Jitter may affect the timeliness of data being transmitted.

Data Representation

Data is collection of raw facts which is processed to deduce information.

There may be different forms in which data may be represented. Some of the forms of data used in communications are as follows:

    • Text
      Text includes combination of alphabets in small case as well as upper case. It is stored as a pattern of bits. Prevalent encoding system : ASCII, Unicode
    • Numbers
      Numbers include combination of digits from 0 to 9. It is stored as a pattern of bits. Prevalent encoding system :
      ASCII, Unicode
    •  Images
      An image is worth a thousand words‖ is a very famous saying. In computers images are digitally stored.
    • Pixel

             A Pixel is the smallest element of an image. To put it in simple terms, a picture or image is a matrix of pixel elements. The pixels                   are represented in the form of bits. Depending upon the type of image (black n white or color) each pixel would require different                  number of bits to represent the value of a pixel. The size of an image depends upon the number of pixels (also called resolution)                    and   the bit pattern used to indicate the value of each pixel.

          Example: if an image is purely black and white (two color) each pixel can be represented by a value either 0 or 1, so an image made            up of 10 x 10 pixel elements would require only 100 bits in memory to be stored. On the other hand an image that includes gray may             require 2 bits to represent every pixel value (00 – black, 01 – dark gray, 105 light gray, 11 –white). So the same 10 x 10 pixel image                would now require 200 bits of memory to be stored. Commonly used Image formats : jpg, png, bmp, etc

  •  Audio

    Data can also be in the form of sound which can be recorded and broadcasted. Example: What we hear on the radio is a source of data or information. Audio data is continuous, not discrete.

  • Video
    Video refers to broadcasting of data in form of picture or movie.

DATA FLOW

Two devices communicate with each other by sending and receiving data. The data can flow between the two devices in the following ways.
1. Simplex
2. Half Duplex
3. Full Duplex

Simplex


Figure: Simplex mode of communication

Simplex:

In simplex mode, the communication is unidirectional, as on a one-way street. Only one of the two devices on a link can transmit; the other can only receive which can be represented in the following figure. Keyboards and traditional monitors are examples of simplex devices. In Simplex, communication is unidirectional. Only one of the devices sends the data and the other one only receives the data.
Example: in the above diagram: a cpu send data while a monitor only receives data.

Half Duplex

Figure: Half Duplex Mode of Communication

Half-Duplex:

In half-duplex mode, each station can both transmit and receive, but not at the same time. When one device is sending, the other can only receive, and vice versa which will represent in the following figure. The half-duplex mode is used in cases where there is no need for communication in both directions at the same time; the entire capacity of the channel can be utilized for each direction.

In half duplex both the stations can transmit as well as receive but not at the same time. When one device is sending other can only receive and vice versa (as shown in figure above.)
Example: A walkie-talkie.

Full Duplex


Figure: Full Duplex Mode of Communication

Full-Duplex:

In full-duplex mode (also called duplex), both stations can transmit and receive simultaneously as shown in the following figure. One common example of full-duplex communication is the telephone network. When two people are communicating by a telephone line, both can talk and listen at the same time. The full-duplex mode is used when communication in both directions is required all the time. Example: mobile phones. both stations can transmit and receive at the same time.

PROTOCOL

A Protocol is one of the components of a data communications system. Without protocol communication cannot occur. The sending device cannot just send the data and expect the receiving device to receive and further interpret it correctly. When the sender sends a message it may consist of text, number, images, etc. which are converted into bits and grouped into blocks to be transmitted and often certain additional information called control information is also
added to help the receiver interpret the data. For successful communication to occur, the sender and receiver must agree upon certain rules called protocol.

Direction of Data Flow

 

Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 12: Computer Fundamentals Keyboard Shortcut Keys

by | Jan 6, 2022 | Computer Fundamentals

Computer Keyboard Shortcut Keys

In modern times, there is no confusion in saying that computers have become a very useful part of daily life. If you use the computer frequently, you must have knowledge about the computer shortcut keys.

Computer shortcut keys provide an easier way of navigating and performing commands in computer software. The use of shortcut keys is beneficial for computer users, as it allows them to complete tasks accurately and in less time. Furthermore, by using shortcut keys, you can increase your productivity and reduce the strain caused by repetitive motions.

The computer shortcut keys are a set of one or more keys that generate a particular command to be executed. Shortcut keys are generally executed by using the Alt or Ctrl key with some other keys.

  • Basic Computer Shortcut Keys
  • Microsoft Word Shortcut Keys
  • Microsoft Excel shortcut keys
  • Microsoft PowerPoint shortcut keys
  • Window key Shortcuts
  • F1 – F12 function keys shortcuts
  • YouTube Shortcuts Keys
  • Google Chrome Shortcut Keys

Basic Computer Shortcut Keys with Explanation

The table contains a list of some commonly used basic shortcut keys that work with IBM compatible computers and software. It is highly recommended that all users should use these keys and try to remember them.

Shortcut Keys Explanation
Alt+Tab It allows you to switch between open programs on a computer. You are required to hold down the Alt key and keep pressing the Tab key to move from one program to another and release the Tab key when it is on the program that you want to open.
Alt+E It is most often used to access Edit Option in the current program. There are some more uses of ALT+E, which are given below:

  • In Google Chrome, it allows you to open the File Menu option.
  • In Winamp and KMPlayer, it brings up the Toggle playlist editor.
  • In Blender, it enables you to open the Extrude menu.
Alt+F It enables you to access the File menu options in the current program.
F1
  • F1 is the first Function key, and it is used to display help information on every Windows program.
  • For example, in Microsoft Windows, it allows you to open the Microsoft Windows help and support screen by pressing F1 and Window key+F1.
  • Furthermore, it is also used to access the Microsoft Office task pane by pressing Ctrl+F1.
F2 It provides users the option to rename an icon or a file which user selects.
In MS word, if you press Ctrl+F2, the print preview option opens.
F5 It is mainly used to refresh the current window or contents of a file or a folder.
Additionally, if you press Ctrl + F5 or Shift + F5 in a web browser, it reloads that web page irrespective of the cached content, and re-download the whole content of the web page.
Ctrl+A It allows you to select the entire content of a page, including images and other objects.
Ctrl+B It offers users with the option to bold the selected text of a page. It also has the various uses in different internet browsers, like in Firefox and Netscape, it is used to view the bookmarks, and in Internet Explorer, used to display the favorites.
Ctrl+C It is used to copy the selected content, including other objects of a page.
Ctrl+V It offers users with the option to paste the copied data. You need to copy data once, and then you can paste it any number of times.
Ctrl+D It is mostly used in internet browsers to add the current site to a bookmark or favorite.
Ctrl+F It provides users with the option to find or search text in the current document or window.
Ctrl+I It allows the user to italicize and un-italicize the selected text.
Ctrl+N It allows the users to create a new or blank document in Microsoft applications and some other software. It is also used in internet browsers to open a new tab.
Ctrl+O It is widely used to open a file in the current software.
Ctrl+K It has various uses, depending on the program. For example, in some applications, it is used to insert a hyperlink, and in Internet browsers, it focuses on the search bar. Such as:

  • In Chrome, it opens Omnibox (search bar)
  • In Firefox, it opens search bar.
  • In Internet Explorer, it duplicates a current tab
  • In Opera, it checks e-mail.
Ctrl+P It is used to open the print preview window for the current page or document. For example, if you press Ctrl+P when a browser or any other document window is open, you will see a print preview window of this page.
Ctrl+S It is used to save the document or a file. You can also use Shift+F12 to save the file in Microsoft Word.
Ctrl+Y Its use is to redo any undo text and other objects, and it is also used to repeat the last performed action.
Ctrl+Z It is used to undo the content and other objects. For example, if you have deleted the data by mistake, you can retrieve this data by pressing Ctrl+Z immediately.
Shift+Insert It is used to paste the copied item.
Shift+Delete It is primarily used to delete the selected text, and it also provides the option to delete any folders or a file permanently.
Home It is mainly used to bring the typing cursor to the starting of the line, which you are currently typing. If you press Ctrl+home, it returns the cursor to the beginning of a document, web page, or cell.
End It is used to move the typing cursor at the end of the line, and it is also used to move the cursor to the end of the document by pressing Ctrl+End.
Alt+Enter It is widely used to access the properties of the selected item, such as file, folder, or any other objects.
Alt+F4 It is used to close the currently open window. For example, if you press Alt+F4 when the browser window is open, it will close the browser window and other open tabs. Additionally, you can use this key to shut down the system, for that you need to press Alt+F4 on desktop screen, and you will see a dialog box then click OK button, the system will shut down.
Ctrl+Esc It will open the start menu. You can also use the Window Key to open the start menu.
Ctrl+Shift+Esc It provides users with the benefit to quickly open the Windows Task Manager in all versions of Windows since Windows 95.
Shift+Home By pressing Shift and Home keys together, you can select all text from the current position of the cursor to the beginning of a line.

Microsoft Word Shortcut Keys

A simple list of Microsoft Word shortcut keys is given below with explanation.

  • Ctrl+A: It is used to select all content of a page, including images and other objects.
  • Ctrl+B: It provides users with the option to bold the selected item of a page.
  • Ctrl+C: Its use is to copy the selected text, including other objects of a file or page.
  • Ctrl+D: It is used to access the font preferences window, which offers several options such as font size, font style, font color, etc.
  • Ctrl+E: It is used to align the selected item to the center of the screen.
  • Ctrl+F: It helps users to find or search data in the current document or window.
  • Ctrl+G: It is used to Go To or jump to any page. When you press Ctrl+G, a dialog box appears, which offers you various options such as find, replace, and Go to. For example, you have 15 pages in your file, and you want to visit page number 4, then enter number 4 in the given box and press the Go To It will take you to the desired page. As shown in the below figure:
    Computer Shortcut Keys
  • Ctrl+H: It is used to replace the words or sentences in a file. For example, if by mistake you have written spple instead of apple at many places in your file, you can replace it with the apple in one go.
  • Ctrl+I: It offers an option to italicize and un-italicize the highlighted text.
  • Ctrl+J: It is used to Justify (distribute your text evenly between the margins) the selected text.
  • Ctrl+K: It allows you to insert the hyperlink. For example, http://www.javatpoint.com
  • Ctrl+L: It is used to adjust (align) the selected content to the left of the screen.
  • Ctrl+M: It provides users with the option to indent the As shown in the below picture:
    Computer Shortcut Keys
  • Ctrl+N: It is used to open a new or blank document in Microsoft applications and some other software.
  • Ctrl+O: It is used to open the dialog box where you can choose a file that you want to open.
  • Ctrl+P: It is used to open the print preview window of a document or a file. It can also be done by pressing Ctrl+F2 and Ctrl+Shift+F12.
  • Ctrl+Q: Its use is to align the selected paragraph to the
  • Ctrl+R: It offers users the option to align the line or selected content to the right of the screen.
  • Ctrl+S: Its use is to save the document or a file.
  • Ctrl+T: It gives users the benefit of creating a hanging indent for a paragraph. For better understanding, see the below image:
    Computer Shortcut Keys
  • Ctrl+U: It is used to underline the selected text.
  • Ctrl+V: It is used to paste the copied data. It allows you to copy data once, and then you can paste it any number of times. You can also paste the data by using Shift+Insert.
  • Ctrl+W: Its use is to close the currently open document or a file quickly.
  • Ctrl+X: If you want to cut some text, you can use this key to cut the selected content. You can also paste it by using Ctrl+V.
  • Ctrl+Y: It allows the users to redo the last action performed in a file. For example, you have written a word mango; you can repeat this word multiple times by pressing Ctrl+Y.
  • Ctrl+Z: It is used to get back the deleted item. For example, if you have deleted the data by mistake, you can press Ctrl+Z to retrieve (Undo) the deleted data. It can also be done by pressing Alt+Backspace.
  • Alt+F, A: It allows users to use the Save As option, which means to save a file with a different name. For that, you need to press Alt+F, which displays a dialog box or a page, then press A for Save As option. It can also be done simply by pressing
  • Ctrl+Shift+L: This key is used to create a bullet point in the file quickly.
  • Ctrl+Shift+>: It increases the font size by +1pts up to 12pt thereafter increases by +2pts.
  • Ctrl+Shift+<: It is used to decrease the font If the font size is 12pt or lower; it decreases the font by -1pts, and if the font size is above 12, it decreases the font by +2pts.
  • Ctrl+]: Its use is to increases the font size by +1pts.
  • Ctrl+[: It is used to decreases the font size by -1pts.
  • Ctrl+/+C: It offers users the option to insert a cent sign (¢).
  • Ctrl + (Left arrow ←):I t allows users the benefit to move one word to the left in the line or a paragraph.
  • Ctrl + (Right arrow →): It is used to move one word to the
  • Ctrl+Shift+*: It is used to show or hide non-printing characters.
  • Ctrl + (Up arrow ↑): This key is used to move the typing cursor to the beginning of the line or paragraph.
  • Ctrl + (Down arrow ↓): It enables you to move the typing cursor to the end of the paragraph.
  • Ctrl+Delete: It allows users to delete a word to the right of the cursor.
  • Ctrl+Backspace: It allows users to delete a word to the left of the cursor.
  • Ctrl+End: Its use is to move the cursor to the last of the document.
  • Ctrl+1: It is used to give a single line space. For example, to make the 1.0 space between the lines of a paragraph.
  • Ctrl+2: It is used to give the double line space. For example, to make the 2.0 space between the lines of a paragraph.
  • Ctrl+5: It is used to make the 5 space between the lines of a paragraph.
  • Ctrl+Spacebar: It enables you to reset the selected text to the default font.
  • Ctrl+Home: It allows you to move the cursor to the beginning of the document.
  • Ctrl+Alt+1: It changes text format to heading 1.
  • Ctrl+Alt+2: It changes text format to heading 2.
  • Ctrl+Alt+3: It changes text format to heading 3.
  • Alt+Ctrl+F2: It is used to open the new file or a document.
  • Ctrl+F1:I ts use is to open the task pane in some Microsoft office versions, in word 2016, it is used to hide and show the ribbon as shown in the below image:
    Computer Shortcut Keys
  • Ctrl+Shift+F6: It allows the users to switch between open documents in Microsoft Word.
  • F1: The function key F1 is used to open the help and support
  • F4: It enables you to repeat the last action performed. For example, when you want to retype the last typed word multiple times, you can use this key.
  • F5: It is used to access the find and replace dialog box, including Go to
  • F7: It provides users the advantage to check spelling and grammar of selected text or document.
  • Shift+F3: It is used to use the change case option where you can change the text from uppercase to lowercase or a capital letter at the beginning of every word.
  • Shift+F7: It offers users the option to check the thesaurus of the selected word. You need to select the word and press this key. As shown in the below picture:
    Computer Shortcut Keys
  • Shift+Alt+D: It is used to insert the current date.
  • Shift+Alt+T: Its use is to insert the current time.

Microsoft Excel shortcut keys

If you work on Microsoft Excel, you can use the number of keyboard shortcut keys to speed up your work and make it more convenient. We have tried to provide a simple list of shortcut keys.

Computer Shortcut Keys

The following table contains the commonly used shortcut keys for Microsoft Excel with description.

Shortcut Keys Description
Ctrl+Shift + ; It is used to insert the current time.
Ctrl+; It is used to enter the current date.
Shift + F3 Its use is to open the Excel formula’s window.’
Shift + F5 It provides users the option to display the find and replace dialog box.
Ctrl + A Its use is to select or highlight all contents of a worksheet.
Ctrl + B It allows you to bold all selected items of an Excel sheet. It can also be done by pressing Ctrl+2.
Ctrl + C It is used to copy the selected content of a worksheet.
Ctrl + D It enables you to fill down the cells with the content of the selected cell. As shown in the below picture:
Computer Shortcut Keys
Ctrl + F It offers the option to open find and replace dialog box quickly. You can also use Shift + F5 for it.
Ctrl + G It is used to open the go-to option dialog box where you can go to the specific cell. It can also be done by using F5.
Ctrl + H It allows you to find and replace the word or sentences in a file. For example, if by mistake you have written a somputer instead of the computer at many places in your sheet, you can replace it with the computer in one go.
Ctrl + I It is used to put italics on all cells in the selected section. It can also be done by pressing Ctrl+3.
Ctrl + K It provides the option to insert a hyperlink in a file.
Ctrl + L It enables you to access the create table dialog box.
Ctrl + N Its use is to open the new document or a workbook.
Ctrl + O It offers users the option to open the dialog box where you can choose a file that you want to open. You can also use Ctrl+F12 to open a file.
Ctrl + P It allows you to print a current sheet or a document quickly.
Ctrl + Q It is used to display the quick analysis options for the selected cells with data. As shown in the below image:
Computer Shortcut Keys
Ctrl + R It allows you to fill the cells to the right with the content of the selected cell. As shown in the below screenshot:
Computer Shortcut Keys
Ctrl + S Its use is to save the document. It can also be done by using Alt+Shift+F2.
Ctrl + T It offers users the option to display the create table dialog box.
Ctrl + U It is used to underline all selected cells. You can also use the shortcut key Ctrl+4 to underline the cells in the Excel sheet.
Ctrl + V It provides users the option to paste the copied data onto the Excel sheet. You are required to copy the data once, and then you can paste it any number of times.
Ctrl + W It is used to close the currently open document or a file quickly. It can also be done by pressing Ctrl+F4 shortcut keys.
Ctrl + X It allows users the option to cut the entire data of the selected cells in an Excel sheet.
Ctrl + Y It provides users the option to redo any undo contents.
Ctrl + Z It is used to undo (get back) the deleted item. For example, if you have deleted the data by mistake, you can press Ctrl+Z to retrieve the deleted data. It can also be done by pressing Alt+Backspace.
Ctrl + Page up & Page Down It allows you to move from one worksheet to another worksheet in the same Excel file.
Ctrl + F6 It enables the users to move from one document to another document in Microsoft Excel. It can also be done by pressing Ctrl+Tab.
Ctrl + F9 It enables users the option to minimize the current window.
Ctrl + F10 It uses to maximize the currently selected window.
F1 It is used to open the help screen window.
F2 It allows you to edit the selected cell in the Excel sheet.
F4 It provides users the option to repeat the last action. For example, if you change the red color of the text in a cell, by pressing F4, you can apply the same text color in another cell.
F7 It is used to check the spelling of the selected text.
F10 The function key F10 is used to activate the menu bar. For example, if you want to open the file menu, you need to press F10, then F.
F11 Its use is to create a chart in Excel.
F12 It enables you to use the Save As option, which allows you to save a file with a different name. It can also be done by using Alt+F2.
Alt + = It allows you to use the formula to add the data of all the above cells.
Ctrl+Shift+” It allows you to copy the content of a cell and to paste it into a cell, which is just below it. It can also be done by using Ctrl+” key. For example, if you have written “Excel” in cell B1 and its below cell is B2, by pressing Ctrl+Shift+” or Ctrl+’ the word “Excel” will be copied in cell B2.
Ctrl + Shift + ! It is used to apply comma format in numbers. For example, as shown in the below image:
Computer Shortcut Keys
Ctrl + Shift + $ Its use is to apply currency format to numbers. As shown in the below screenshot:
Computer Shortcut Keys
Ctrl + Shift +% It provides users the option to apply percentage sign to numbers. For example, see the below picture:
Computer Shortcut Keys
Ctrl + Space It enables you to select the entire active columns.
Shift + Space It enables you to select the entire active rows.
Ctrl + (Right arrow →) It allows the users to move the cursor to the next cell, which contains the text.
Ctrl + 1 It is used to open the format cells dialog box where you can change the text format like text color, font size, font style, text alignment, etc. It can also be done by pressing Ctrl+Shift+F or Ctrl+Shift+P.
Ctrl + 5 Its use is to put the strikethrough to all selected cells. As shown in the below picture:
Computer Shortcut Keys
Ctrl + 9 Its use is to hide the selected rows in the worksheet.
Ctrl + Shift + ( Its use is to show (unhide) the hidden rows.
Ctrl + 0 It is used to hide the selected columns.
Ctrl + – (Minus) It will open a delete dialog box where you can delete a selected row or column.
Ctrl + Shift + = It will open the insert dialog box where you can insert the new row or a column.
Ctrl + Shift + ^ It is used to make an exponential form of any number. For example, you have written a number 12345 in the worksheet, and if you press Ctrl+shift+^, the number will be changed 1.23E+05 in exponential form.
Ctrl + Shift + & It offers users the option to make a border around the selected cells.
Ctrl + Shift+ _ It offers users the option to remove a border around the selected cells in a worksheet.
Ctrl+Shift+Spacebar It is used to select the entire worksheet.
Ctrl + Home It allows the users to move the cursor to the beginning (cell A1) of the worksheet.
Ctrl + End It is used to move the cursor to the last cell with text on the worksheet.
Shift + Page Up It allows you to select all the cells located above the selected cell.
Shift + Home It enables you to select all cells to the left of the current active cell.
Shift + (Up Arrow ↑) It enables you to extend the selected area up by one cell.
Shift + (Down Arrow ↑) It enables you to extend the selected area down by one cell.
Alt + Enter It allows the users to write in multiple lines in one cell. For example, if you are typing in a cell, it enables you to move on the next line in one cell by pressing Alt+Enter.
Alt + ‘ It is used to access the style dialog box.
Ctrl + F3 It is used to open the name manager in Microsoft excel.
Ctrl + F5 Its use is to restore the Window size.
Ctrl + F11 It is used to insert a macro sheet in Microsoft excel.
Alt + F8 It is used to display the macro dialog box.
Alt + F11 It provides users the option to open the Visual Basic editor.
Alt + Shift + F1 It enables you to create a new worksheet in Microsoft Excel.

Microsoft PowerPoint shortcut keys

Computer Shortcut Keys

Shortcut keys Explanation
(Slide number) + Enter It is used to jump to the desired slide during a slide show. For example, during the slide show, if the 5th number slide is being viewed, and you want to jump to the 8th number slide, press the 8-number key and then the Enter key.
Shift+Alt+T or D It allows you to open the date and time window to insert the current date and time.
Ctrl+A It provides users the option to select all items like the text in a text box and objects in a slide. In slide sorter view, it is used to select all slides. Furthermore, in slide show, its use is to display the various options as shown in the below mage:
Computer Shortcut Keys
Ctrl+B It enables you to add or remove bold to the selected content.
Ctrl+C Its use is to copy the selected text, including other objects in the slide. It can also be done by pressing Ctrl+Insert.
Ctrl+D It is used to create a copy of the selected slide. For example, if you want to add a copy of any slide, you need to select it, and press the Ctrl+D shortcut keys.
Ctrl+E It enables you to align the line or selected text to the center of the slide.
Ctrl+F It provides users the option to find or search content in the file.
Ctrl+H It is mostly used to replace a word or sentences in the file, and in slide show, it is also used to hide the cursor or any activated tools, like the pen or a highlighter tool.
Ctrl+I It allows you to add or remove italicize to the selected text. Furthermore, in slide show view, it is also used to change the cursor to the highlighter tool. You need to hold the mouse button to use the highlighter on the screen.
Ctrl+J It enables you to Justify (align your text evenly across the slide) the selected text.
Ctrl+K It offers an option to insert a hyperlink.
Ctrl+L Its use is to align the content or selected line to the left side of the slide.
Ctrl+M It is used to insert the new or blank slide just below the selected slide.
Ctrl+N It enables you to create a new or blank file in another PowerPoint window.
Ctrl+O It is used to open the dialog box or page, where you can select a file that you want to open. You can also use Alt+Ctrl+F2 to open a file.
Ctrl+P It provides users with the option to open the Print Preview page to print the file. It can also be done by using Ctrl+Shift+F12 or Ctrl+F2 shortcut keys. 

Additionally, in slide show view, it is also used to change the cursor to the pen tool.
Ctrl+R It moves the text or selected paragraph to the right side of the slide.
Ctrl+S It allows you to save the open file. You can also use the Shift+F12 to save a file.
Ctrl+T It is used to open the font window, where you can adjust the font size, style, type, etc. It can also be done by pressing Ctrl+Shift+F shortcut keys.
Ctrl+U It enables the users to add or remove an underline from the selected content.
Ctrl+V It is used to paste the copied text, slides, and other objects in the file. You need to copy the data once, and then you can paste it multiple times. You can also paste the data by using Shift+Insert.
Ctrl+W It enables you to close the currently open document.
Ctrl+X It allows you to cut the selected item.
Ctrl+Y Its use is to repeat the last performed action. It can also be done by pressing the function key F4.
Ctrl+Z It is used to undo (get back) the deleted text, slide, and other objects. Suppose, by mistake; you have deleted any slide, you can get back it by using this shortcut key.
Shift+F3 It allows the users to change the selected text into uppercase or lowercase and can be used to change the first letter of a word into a capital letter. If the text is not selected, only the first word after the cursor will be changed.
Shift+F5 It helps to start the slide show from the selected slide. For example, if you have 20 slides in your file and you want to start a slide show from the 5th slide, you need to select the 5th slide, and press Shift+F5.
Shift+F7 It is used to check the thesaurus of the selected word. As shown in the below image:
Computer Shortcut Keys
Shift+F9 Its use is to show or hide the grid on the slide in Microsoft PowerPoint.
B It is used to change the display to black during slide show, and again press B to get back to the slide show.
F1 It is used to open the help menu, and in slide show view, its use is to display the slide show help window that provides a list of shortcuts for use in a slide show.
F5 It allows the users to view the slide show of all the slides.
F7 It provides users the benefit of checking grammar and spelling to the selected word.
F12 It allows you to use the Save As option, in which you can save a file with a new name.
Ctrl+F1 It is used to show or hide the Ribbon.
Ctrl+Shift+> It is used to increase the font size of the selected text. It can also be done by pressing Ctrl+].
Ctrl+Shift+< It is used to decrease the font size of the selected text. It can also be done by pressing Ctrl+[.
Ctrl + Shift + = (Equal sign) It helps users to change the selected text into a subscript. For example, plain text subscript text, X2 → X2
Ctrl+Spacebar It allows you to change the selected text to the default font size and type.
Ctrl+Home Its use is to move the cursor to the first slide. For example, if you have 50 slides in your file, and the cursor is on 45th slide, by pressing Ctrl+Home, you can move the cursor to the first slide.
Ctrl+End It is used to move the cursor to the last slide. For example, your PowerPoint file has 100 slides, and you want to move the cursor to the last slide, you can press Ctrl+End.
Ctrl+Backspace It will delete the word to the left of the cursor.
Ctrl+Delete It will delete the word to the right of the cursor
Alt+N, P It enables you to insert a picture in your file. You need to press Alt and N keys together then press P.

Window key Shortcuts

The following table contains several Windows (Winkey) shortcuts keys:

Shortcut Keys Explanation
Window key It provides users the option to open and close the start menu.
Winkey + D It is used to minimize all opened windows and to restore the minimized windows. For example, if you have opened different programs such as Google Chrome, Microsoft Word, then you can press window key and D together to minimize all opened windows.
Winkey + E It helps users to open a computer window or hard disk drives.
Winkey + M It allows users to minimize all opened program windows.
Winkey + Shift + M It is used to restore all windows, which are minimized by using Winkey+M and Winkey+D.
Winkey + Tab It offers users the option to switch between open programs by using Aero Flip 3-D on a computer. You are required to hold down the Window key and keep pressing the Tab key to move from one program to another, release the Tab key when it is on the program that you want to open.
Winkey + F It will show a window where you can search or find data available in your computer.
Winkey + L It is used to lock the computer or switch users.
Winkey + R Its use is to open the Run dialog box where users can open various programs. For example, if you want to open Microsoft Word, you are required to press Winkey + R, and type winword in opened run window then press Enter key.
Winkey + U It allows you to open the ease of access center window, which enables you to access various options like start magnifier, on-screen keyboard, start narrator, etc.
Winkey + Pause /Break Its use is to open the system properties dialog box.
Winkey + Number It provides users the option to open the programs pinned to the taskbar as per their position on the taskbar. For example, as shown in the below image, the Internet Explorer is located on 1stposition on the taskbar; by pressing Winkey+1, the Internet Explorer will be opened. Thus, if you press Winkey+6, the Excel will be opened as it is located on the 6th position on the taskbar.
Window key Shortcuts
Shift + Winkey + Number It allows you to open the new window of the program pinned to the taskbar according to their location on the taskbar. For example, as shown in the below image, the Internet Explorer is located on 1st position on the taskbar; by pressing Shift+Winkey+1, the Internet Explorer will be opened. If you press this shortcut key again while opening Internet Explorer, it will open a new window of Internet Explorer again.
Window key Shortcuts
Alt + Winkey + Number It is used to open the jump list for the program pinned to the taskbar as per their position on the taskbar. For example, as shown in the below picture: It is done by pressing Alt + Winkey + 1.
Window key Shortcuts
Winkey + V Its use is to open the Clipboard app.
Winkey+ up arrow (↑) This key is used to maximize the window.
Winkey+ downarrow (↓) It is used to minimize the window.
Winkey+ leftarrow (←) It helps users to maximize the window to the left side of the screen.
Winkey+ right arrow (→) Its use is to maximize the window to the right side of the screen.
Winkey + P It allows users to choose a presentation display mode. As shown in the below image:
Window key Shortcuts
Winkey + X It provides users the option to open the windows mobility center where you can adjust volume, brightness, and more.

F1 – F12 function keys shortcuts

The function keys range from F1 to F12 on a computer keyboard. These keys perform a special function defined by the operating system or by a currently running program. These keys can be used with Alt or Ctrl keys to perform different functions.

function keys shortcuts

The function keys may perform different tasks on different keyboards. As some laptop’s and small keyboards’ function keys are used to change the screen brightness, volume, and perform other specific functions. The common shortcut keys for Windows and macOS are given below:

F1

  • It is used to open the help window in almost every program.
  • It is also used to enter the BIOS or CMOS Some computers allow you to enter the BIOS setup by using different keys such as F2, F10, Delete, Esc.
  • If you press Window + F1, it will open the Microsoft Windows help and support center.

F2

  • In Microsoft Windows, it is used to rename an icon, file, or folder which the user selects.
  • In Microsoft Excel, the key F2 allows you to edit the selected cell in the Excel sheet.
  • In Microsoft word, if you press Ctrl+F2, the print preview window will open, and Alt+Ctrl+F2 will open the new file or a document.
  • Furthermore, it is also used to enter the CMOS setup.

F3

  • It is mostly used to open a search feature for many programs.
  • In MS-DOS or Windows command line, it provides users the option to repeat the last command entered.
  • In Microsoft Word, if you press Shift + F3, it allows you to change the selected text from uppercase to lowercase or a capital letter at the beginning of every word.
  • In Microsoft Outlook, if you press Windows Key + F3, it will open the advanced find window.
  • Furthermore, it is also used to open the Mission Control on an Apple computer.

F4

  • Its use is to open the find window in Windows 95 to XP.
  • It is used to open the address bar in Internet Explorer as well as Windows Explorer.
  • In Microsoft Word, it allows you to repeat the last action performed. For example, if you want to retype the last typed word or sentences multiple times, you can use this key.
  • If you press Alt+F4, it will close the currently open window in Microsoft Windows. Furthermore, it is also used to shut down the system, for that you need to press Alt+F4 on desktop screen, you will see a dialog box then click OK button, and the system will be shut down.

F5

  • It is mainly used to refresh or reload the page or document window.
  • If you press Ctrl + F5 or Shift + F5 in a web browser, it completely refreshes the web page, clear the cache, and re-download the whole content of the web page.
  • It provides users the option to access find, replace, and Go To dialog box in Microsoft Word.
  • Furthermore, it is also used to start the slideshow in PowerPoint.

F6

  • It helps users to move the cursor to the address bar in Internet browsers such as Internet Explorer, Mozilla Firefox, Google Chrome, etc.
  • In Microsoft Word, if you press Ctrl+Shift+F6, it allows you to switch between other open Word documents.
  • Furthermore, it reduces laptop speaker volume (on some laptops).

F7

  • It is commonly used to check spelling and grammar of a document in Microsoft programs such as Microsoft Word, Outlook, etc.
  • If you press Shift+F7, it allows you to check the thesaurus of the selected word in Microsoft Word, PowerPoint.
  • It provides users the option to turn on Caret Browsing in Mozilla Firefox.
  • It is also used to increase the laptop speaker volume (on some laptops).

F8

  • The F8 function key allows users to enter the Windows startup menu, generally used to access Windows Safe Mode.
  • It is also used to access the Windows recovery system by some computers but may require a Windows installation CD.
  • Furthermore, it displays a thumbnail image for all workspaces in macOS.

F9

  • It is used to send and receive an email in Microsoft Outlook.
  • It is also used to refresh document in Microsoft Word.
  • Its use is to access the Measurements toolbar in Quark 5.0.
  • It helps to reduce screen brightness on some laptops.
  • It offers users the option to display a thumbnail for each window in a single workspace on macOS 10.3 or later versions.
  • On Apple computer, if you press Fn and F9 keys together, the mission control will open.

F10

  • It allows you to activate the menu bar of an open application in Microsoft Windows.
  • Shift+F10 is used to open the right-clicking options on a selected word, icon, file, or Internet link. As shown in the below screenshot:
    function keys shortcuts
  • It allows users to access the hidden recovery partition on Compaq, HP, and Sony computers.
  • It provides users the option to enter CMOS setup on some computers.
  • It is also used to increase the screen brightness on some laptops.
  • On macOS 10.3 or later, it displays all open Windows for the active program.

F11

  • It is used to enable and disable the full-screen mode in all modern internet browsers.
  • It allows users the option to access the hidden recovery partition on eMachines, Gateway, and Lenovo computers.
  • On macOS 10.4 or later, it is used to hide all open windows and shows the desktop.

F12

  • It is used to open the Save as option where you can save a file with a different name in Microsoft Word, Excel, etc.
  • By pressing Ctrl+F12, you can open a file or document in Word, Excel, etc.
  • Shift+F12 is used to save a file in Microsoft Word like we do by using Ctrl+S.
  • If you press Ctrl+Shift+F12 in Microsoft Word, it will open the print preview window of a document or a file like we do by using Ctrl+P.
  • F12 is also used to open a firebug or debug tool of browser.
  • On Apple computer 10.4 or later, F12 is used to display or hide the dashboard.
  • Furthermore, it provides a list of bootable devices on a computer at startup. You can choose that device from the list, which you have connected to your PC to boot from, Such as hard drive, DVD drive or CD, floppy drive, USB drive, and network.

YouTube Shortcuts Keys

Shortcut Keys Description
Spacebar or K It is used to play and pause a video on YouTube.
Zero or Home If you press zero (0) key while watching a video on YouTube, it will start that video again from the beginning.
End It provides users the option to jump to the end of the video. If you are watching a playlist, it will play the next video in the playlist.
Right Arrow (→) It is used to fast forward the video by five seconds each time you press the key.
Left Arrow (←) Its use is to fast backward the video by five seconds when you press the key.
J and L The J key is used to rewind the video with 10 seconds, and L is used to forward the video with 10 seconds.
Numbers (1 to 9) Any number of keys from 1 to 9 is used to jump the video in the form of a percentage. For example, if you press 1 while watching a video, the video will forward 10%. If you press 2, the video will forward 20%. Thus, if you press 8, the video will forward 80%.
F It allows you to switch the video to full-screen mode or theater mode.
T Its use is to switch between theater mode and normal mode.
Up Arrow (↑) It is used to increase the volume while watching video on full-screen mode. Whereas during normal mode, you have to click on the video before pressing this key.
Down Arrow (↓) It is used to decrease the volume while watching video on full-screen mode. On normal mode, you have to click on the video before using this key.
M It enables you to mute the video on YouTube.

Google Chrome Shortcut Keys

The below list contains all widely used shortcut keys on the Google Chrome browser.

Key Combination Explanation
Alt + Home It is used to open the homepage in the Chrome browser.
F11 It offers users the option to show the current website in full-screen mode, and press F11 again to exit this mode.
Alt + Left Arrow Its use is to return to the previous page.
Alt+Right Arrow It is used to goto the next page.
Ctrl + Plus (+) It provides users the option to zoom in a page.
Ctrl + Plus (-) It provides users the option to zoom out a page.
Ctrl + 0 It is used to reset browser zoom to the default size.
Ctrl+1 to 8 It offers users the option to switch to one of the opened tabs on the tab bar. For example, if you press Ctrl+3, the third tab will appear.
Ctrl + 9 It allows you to switch to the opened last tab on the tab bar.
Ctrl + A It is used to select all content on a page.
Ctrl + D It is used to add the bookmark for the currently opened page.
Ctrl + F It enables you to open the find bar to search text on the current page.
Ctrl+Enter It helps users to add.Com extension in web address quickly. For example, if you type ‘javatpoint’ in the address bar and press Ctrl+Enter, it will be completed automatically, such as javatpoint.com.
Ctrl+Shift+Del It provides users the option to access the clear browsing data window to clear the browsing history, cookies, and other private data.
Ctrl + O It allows you to open a file in the browser.
Ctrl + Shift + O It is used to open the bookmark manager in the Chrome browser.
Ctrl + H Its use is to open the history window where you can manage your browser history as required.
Ctrl + J It enables users to open the downloads window in a new tab.
Ctrl+K or E It offers users the benefit of moving the text cursor to the searchbar, where you can search any query.
Ctrl + L It takes the cursor to the browser address bar and selects all the text available in the address bar
Ctrl + N Its use is to open the new browser window.
Ctrl + P It is used to open the print window and allows you to print the pages.
Ctrl + Shift + N It provides users the option to access a new window in incognito mode. Incognito mode or private mode allows you to search query in a unique sandbox web session. It provides you the option to temporary control your browser history, as when you close your browser window, it forgets to store your history.
Ctrl + R or F5 It is used to refresh the current page on the browser.
Ctrl + S It allows you to open the save as window where you can save the currently opened web page.
Ctrl + T It offers users the option to open a new tab on the browser quickly.
Ctrl + U It enables you to display the source code of the web pages.
Ctrl + W It is used to close the current tab.
Ctrl+Tab It allows you to move to the right side of the browser from one tab to another tab.
Ctrl+ Shift + Tab It allows you to move from one tab to another tab to the left side of the browser.
Ctrl+Shift+W It provides users the option to close the currently selected window.
Ctrl + Left-click It allows users to open a search result link in the new tab without leaving the current page.
Ctrl + Shift Left-click It enables you to open a search result link in the new tab and switch to the new tab.
Spacebar It is used to move down the page.
Shift + Spacebar It is used to move up the page.
End Its use is to move at the bottom of the page.
Home Its use is to move at the beginning or top of the page.
Ctrl+Shift+T It provides users the benefit to reopen the last tab you closed. If you have closed multiple tabs, you can also reopen those tabs by pressing this shortcut key multiple times.
Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 11: Computer Fundamentals Internet Intranet Website

by | Jan 6, 2022 | Computer Fundamentals

Internet

Internet is a global network that connects billions of computers across the world with each other and to the World Wide Web. It uses standard internet protocol suite (TCP/IP) to connect billions of computer users worldwide. It is set up by using cables such as optical fibers and other wireless and networking technologies. At present, internet is the fastest mean of sending or exchanging information and data between computers across the world.

It is believed that the internet was developed by “Defense Advanced Projects Agency” (DARPA) department of the United States. And, it was first connected in 1969.

Why is the Internet Called a Network?

Internet is called a network as it creates a network by connecting computers and servers across the world using routers, switches and telephone lines, and other communication devices and channels. So, it can be considered a global network of physical cables such as copper telephone wires, fiber optic cables, tv cables, etc. Furthermore, even wireless connections like 3G, 4G, or Wi-Fi make use of these cables to access the Internet.

Intranet

Intranet is the system in which multiple PCs are connected to each other. PCs in intranet are not available to the world outside the intranet. Usually each organization has its own Intranet network and members/employees of that organization can access the computers in their intranet.

Intranet

Each computer in Intranet is also identified by an IP Address which is unique among the computers in that Intranet.

Similarities between Internet and Intranet

  • Intranet uses the internet protocols such as TCP/IP and FTP.
  • Intranet sites are accessible via the web browser in a similar way as websites in the internet. However, only members of Intranet network can access intranet hosted sites.
  • In Intranet, own instant messengers can be used as similar to yahoo messenger/gtalk over the internet.

Differences between Internet and Intranet

  • Internet is general to PCs all over the world whereas Intranet is specific to few PCs.
  • Internet provides a wider and better access to websites to a large population, whereas Intranet is restricted.
  • Internet is not as safe as Intranet. Intranet can be safely privatized as per the need.

Extranet

Extranet is a part of an organization’s intranet. It is a communication network that is based on internet protocols (TCP/IP). It provides controlled access to firm’s intranet to its trading partners, customers, and other businesses.

Some of the benefits of extranet:

  • It acts as a single interface between the company and its trading partners.
  • It automates the firm’s processes like automatically places an order with suppliers when inventory drops.
  • It improves customer service by providing customers a platform to resolve their queries and complaints.
  • It enables the firm to share information with trading partners without engaging in paper-based publishing processes.
  • It streamlines business processes that are repetitive in nature, such as ordering from a vendor on a regular basis.

How is Extranet Established?

It is set up in the form of a Virtual Private Network as it is prone to security threats due to the use of the internet to connect outsiders to an organization’s intranet. VPN can assure you a safe network in a public network such as the internet. The transmission control protocol (TCP) and internet protocol (IP) are used for the data transfer.

VPN assures secure transactions based on Internet Protocol Security Architecture (IPSEC) protocol as it provides an extra security layer to TCP/IP protocol, which is used for data transfer in the extranet. In this layer, the IP packet is encapsulated to form a new IP packet, as shown below:

Extranet

Furthermore, to provide more security to Intranet, the following two measures are also taken by an organization:

  • Firewall: It prevents unauthorized users from accessing the extranet.
  • Passwords: It also prevents unauthorized users, including the company’s employees from accessing the data stored on its server.

Limitations of Extranet:

  • Hosting: If you host extranet pages on your own server, it requires a high bandwidth internet connection, which is may be very expensive.
  • Security: You need extra firewall security if you host it on your own server. It increases the workload and makes security mechanism very complex.
  • Dependency: It is dependent on the internet as outsiders cannot access information without using the internet.
  • Less Interaction: It reduces the face to face interaction between customers, business partners, vendors, etc., which results in poor relationship building.

Difference between Intranet and Extranet:

Intranet Extranet
It is a private network, which cannot be accessed externally. It may not be called a private network, as it can be assessed externally. It provides limited access to authorized outside-users such as vendors, partners, etc.
It connects the employees of the company. It connects the company’s employees with partners.
It is an independent network, not a part or extension of any other network. It is an additional part of company’s Intranet.
Communication takes place only within the organization that owns the network. External users such as suppliers, customers, and partners are allowed to be a part of intranet to get information, updates, about the organization.

Website

Website is a collection of related web pages that may contain text, images, audio, and video, etc. The first page of a website is called a home page. Each website has a specific internet address (URL) that you need to enter in your browser to access a website.

The first website was introduced on 6 August 1991. It was developed by Tim Berners-Lee at CERN. As of January 2018, there were around 1.7 billion websites on the internet.

Website

What is the need for a website?

A popular website is another name of success in modern times as today we are living in a digital world where people are spending most of their spare time on internet browsing news, images, videos, and more. A website is the first thing that appears on the screen of your laptop when you search for a product or service, or any other information online. So, it is very important to have a website whether you are a businessman, organization, online store, etc. Let us understand how a website can help you grow your business!

The benefits of having a website are as follows:

1. Cost-effective: The marketing of products and services through a website is less costly than print advertising, TV, and radio advertising. It also allows you to make changes related to your products and services such as you can edit products’ specifications, features, discount offers, etc.

2. Broder demographic reach: A website can help your business reach people with diverse backgrounds throughout the world.

3. Business credibility: Having a website that is user-friendly and professional looking for your business makes people consider your business more credible than others who don’t have a website to represent their businesses online.

4. 24/7 availability: You can keep your products available for sale around the clock through a website. Customers can buy anytime, and thus you can earn more profits than a traditional storefront.

5. Consumer convenience: It improves the shopping experience of your customers; they can buy your products from the comfort of their home.

6. Build customer rapport: Online presence helps you build and maintain a rapport among your customers. You can also introduce special offers or discounts for your loyal customers.

7. Improves productivity: It saves your time as you don’t need to explain your products or services to each customer separately, as all the information is already available on the website.

8. Educate your customers: You can educate people about the benefits of your products and can show them how they are betters than the competitors’ products.

9. Change location: You can move your business to another location without affecting your sales as customers still can find you through your website.

10. Grow manpower: You can post job openings for vacant positions and allow applicants to check job descriptions and apply online.

11: Personalized email address: It allows you to set up personalized email addresses for employees, companies, partners, etc. You can receive mails on these mail ids and reply accordingly. Furthermore, you can share offers, happy hours, updates, and can get feedback through email.

12. Improve customer service: It allows you to improve customer services such as you can share phone numbers to contact you, and display other relevant information such as order status, delivery status, refund or replacement procedure, etc.

Types of Websites:

A website can be of two types based on the type of webpages:

  • Static Website
  • Dynamic Website

Static website

A static website, as the name suggests, is a website in which pages do not change or remain the same. It is the basic type of website that is easy to create, maintain, and host. You don’t need web programming and database design to create a static website. Its webpages are coded in HTML. The codes are fixed for each page, so the information contained in the page does not change, and it looks like a printed page. However, changes can be made by changing the codes if required.

You can think of it as a brochure for a business that has the same information for every user. So, all users see the same information irrespective of their location, interests, etc., when they open a particular page of a static website.

In the case of a static website, the content or webpage is taken directly form the file stored in the server without requiring any interpreter (application software) to interact with a database to fetch data from the database. So, database and server-site scripting are not required in static websites.

Benefits of a Static Website:

  • It takes less time to create a static website.
  • It is less costly to develop this website.
  • The webpages are delivered at high speed by the servers.
  • Hosting through dedicated servers is available at a low price.
  • It is more secure than dynamic sites as it does not rely on CMS plugins and server-side scripting.

Dynamic website

A dynamic website is a collection of dynamic web pages whose content changes dynamically. It accesses content from a database or Content Management System (CMS). Therefore, when you alter or update the content of the database, the content of the website is also altered or updated.

A dynamic website uses client-side scripting or server-side scripting, or both to generate the dynamic content. For example, when a browser sends a request to the server, the server contacts the application server with further interacts with the database server to fetch the content, which is customized as per the user’s requests and requirements. For example, a Facebook page may appear different to different users as per their friends’ list, interests, location, etc.

Benefits of a Dynamic Website:

  1. It is very quick and easy to make changes in a dynamic website as it is integrated with high-end programming.
  2. The webpages are easier to maintain despite of being full of information and graphics.
  3. E-commerce sites are dynamic as they need to be impressive and have easy navigation from one page to other pages.
  4. It makes your site look professional.
  5. The users can get customized information as per their interests, needs, and profile, etc. For example, facebook.com, flipkart.com, etc.

Difference between Static Website and Dynamic Website:

Static Website Dynamic Website
As the name suggests, Its webpages do not change in terms of design, content, etc. The information or content remains the same. As the name suggests, the webpages keep changing as per users’ requirements such as Facebook profile pages and an E-commerce site. So, the content does not remain the same.
It mainly uses HTML and CSS and does not require server-side scripting, application server, and database. It requires server-side scripting, application server, and database to create and send dynamic webpages to the client.
It has a limited number of pages. It may contain thousands of pages in the database.
Its hosting cost is low, as HTML files need less space on the server. Its hosting cost is higher as dynamic pages need more space on the server.
It requires low maintenance. It requires high maintenance.
It loads quickly as it involves the use of mark-up languages to create a webpage. It takes more time to load due to the more processing time.
It lacks the Content management feature. It makes use of the Content Management Feature.
The content of the webpage cannot be changed during runtime. The webpage content can be changed during runtime.
It does not require interaction with a database. Interaction with the database occurs.
It is more secure or fewer chances of it getting hacked as it doesn’t use plugins. It is less secure and may get hacked easily as it uses many plugins and content sources.
It is more reliable, e.g., whenever the server is down, it is redirected to other nearby nodes. It is less reliable, as it may go down for hours if the server breaks down.

Types of Websites based on their purpose, target audience, etc.

1. Blog: It is a type of website that provides information or in which posts are added regularly in reverse chronological order, latest post or entries on top of the main page, and old ones towards the bottom. A blog is usually owned by a single person or a small group of people.

The content in a blog is written in an informal or conversational style and can be focused on one subject or a wide range of related subjects. Furthermore, the posts are organized into categories if required, e.g., posts that provide similar information can be kept in a separate category.

The content of a blog is generally referred to as a blog post, and it generally appears as posts on a streaming page. The information is regularly updated in a blog, e.g., articles, photos, and videos are added on a daily basis to keep readers engaged and increase the traffic to the blog. It also allows readers to leave a comment about the posts.

2. E-commerce: These types of websites are like online shops where people can buy products through online payment from the comfort of their home, office, etc. Anyone who wants to sell products online can create an E-commerce site instead of investing in setting up a traditional brick-and-mortar shop.

3. Informational: These websites are created to provide free online information to users, e.g., tutorials, news, general knowledge-based sites. Today, you don’t need to visit libraries to read a book, newspaper, novel, etc. owing to the presence of lots of informational sites.

4. Online Community: These sites offer a platform to interact and share ideas with others through internet. You can find people with similar interests and backgrounds and interact with them to fulfil your objectives that may include promoting a product or service, taking feedback about your products, or asking questions related to a survey.

5. Social Media: These sites are created to provide users a platform where they can build their personal profiles with a lot of features such as creating a friend list, sending and accepting friend requests, sending messages, creating and joining groups, and share information with others users, comment on others’ post, pictures, videos, etc.

6. Brochure: It is the simplest type of website which comprises few pages. It is used by small businesses to have a simple online presence or to provide an overview of their business. Such websites are generally static where the content does not change, i.e., the same information is displayed to all users.

7. Non-profit: The sites are created to raise money for social causes such as to provide free medical treatment to poor, free basic education to children, free food to children to prevent malnutrition, etc.

Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 10: Computer Fundamentals Virus

by | Jan 6, 2022 | Computer Fundamentals

Computer Virus

Computer viruses are unwanted software programs or pieces of code that interfere with the functioning of the computer. They spread through contaminated files, data, and insecure networks. Once it enters your system, it can replicate to produce copies of itself to spread from one program to another program and from one infected computer to another computer. So, we can say that it is a self-replicating computer program that interferes with the functioning of the computer by infecting files, data, programs, etc.

There are many antiviruses, which are programs that can help you protect your machine from viruses. It scans your system and cleans the viruses detected during the scan. Some of the popular antiviruses include Avast, Quickheal, McAfee, Kaspersky, etc.

Types of Computer Virus:

Overwrite Virus:

It is the simplest computer virus that overwrites the code of the host computer system’s file with its own malicious code. The content of the infected file is replaced partially or completely without changing the size of the file. Thus, it destroys the original program code by overwriting it with its defective code. The infected files must be deleted or replaced with a new copy as this virus cannot be removed or disinfected.

Append Virus:

As the name suggests, this virus appends its malicious code to the end of the host program’s file. After that, it alters the file’s header in a way that the file’s header is redirected to the start of the malicious code of the append virus. Thus, this code is executed each time the program runs. However, it does not destroy the host program; rather, it modifies it in a way that it holds the virus code and enables the code to run itself.

Macro Virus

Macro virus alters or infects the macros of a document or data file. It is embedded as a macro in a document and adds its codes to the macros of the document. The virus spreads when infected documents or data files are opened in other computers.

It also spreads through software programs, which execute macros such as Ms Word, Ms Excel. Each time a document is opened using these programs, other related documents will also get infected.

The first macro virus, which was named concept, spread through emails with attached Ms Word documents. It infected MsWord 6.0 and Ms Word 95 documents, which were saved using Save As option. Fortunately, it did not cause any harm, except for displaying a message on the screen.

Boot Virus

Boot virus or boot sector virus alters the boot sector program stored in the hard disk or any other storage device such as floppy disks. It replaces the boot sector program with its own malicious version. It infects the computer only when it is used to boot up the computer. If it enters after the boot-up process, it will not infect the computer. For example, if someone forgets to remove the infected floppy disk when the pc is turned off and then turns on this pc, it runs the infected boot sector program during the booting process.

Usually, it enters into your system through corrupt media files, infected storage devices, and insecure computer networks. The spread of this virus is very rare these days due to the decline in the use of floppy disk and use of boot-sector safeguards in the present-day operating systems.

Resident Virus

The resident virus stays permanently in the primary memory (RAM) of the computer. When you start the computer, it becomes active and corrupts the files and programs running on the computer.

Non-resident Virus:

Unlike the resident virus, the non-resident virus does not reside in the memory of a computer. So, it is not executed from the computer’s memory. For example, executable viruses.

Multipartite Virus

Multipartite virus spreads and infects in multiple ways. It infects both the boot sector and the executable files stored on the hard drive simultaneously. When you turn on a computer, the boot sector virus is triggered as it latches on to the hard drive, which has the data for starting up the computer. Once it is triggered, the program files also get infected.

File Infector Virus

It is one of the commonly found computer viruses. It mainly infects the executable files; the files with .com or .exe extensions. The virus becomes active when the infected file is executed. The active virus overwrites the file partially or completely. Thus it may destroy the original file partially or completely.

Computer Worm

Computer worm is similar to a virus but is technically different from the virus. It can replicate and spread like a virus, but unlike viruses, it does not need a host program to spread. Being able to self-replicate it can produce multiple copies of itself. It spreads through networks such as an email sent to an infected email id can infect your system with a computer worm.

Trojan Horse

Trojan horse is a malware like a virus or a worm, but it is technically different from both. It can’t replicate like virus and worm. Trojan horse hides itself in a program. Once you install any such program, the trojan horse enters into your computer. It can provide unauthorized access to your computer, send your files to other computers, and may delete files or can make other unwanted changes in your computer.

Cavity virus:

It is also known as a spacefiller virus. As the name suggests, this virus tends to install itself by occupying the empty sections of a file. It is not easy to detect this virus as it fills the empty spaces without changing the size of the file.

CMOS Virus:

It infects the CMOS, which stands for complementary metal-oxide semiconductor and is a memory chip that contains the system configuration. This virus can erase or reset the system configuration.

Companion Virus:

It resides itself in a file whose name is similar to another program file, which is executed normally. When the program file is executed, the virus gets activated and performs malicious steps such as deleting the files on your computer hard drive. Globe virus is a first known companion virus, which was found in 1992.

Encrypted Virus:

It encrypts its payload to make its detection more difficult. It comprises two parts: an encrypted virus body and a decryptor, which decrypts the virus when it is executed. After decryption, the virus can execute itself in order to replicate and become a resident. Furthermore, it is different from cryptolocker, which is a computer virus that encrypts the hard drive data and holds it for ransom.

Executable Virus:

It is a non-resident computer virus, which resides in an executable file. Whenever the infected file is executed, it infects the other files.

Polymorphic Virus:

It creates its thousands of copies itself; in each copy, it changes the sequence and byte values to evade detection by antivirus software. Even the best antiviruses may not be able to detect this virus. Polymorphic viruses affect data types and functions and generally spread through spam, infected sites, and while using other malware.

Rabbit Virus:

It is also known as wabbit, a fork bomb. It is capable of creating new processes, and each of the new process further creates new processes. This process continues until this virus utilizes all the available resources in the system and system falls short of resources. It may cause the target system to slow down and crash. For example, it is like an Infinite loop that repeatedly creates processes that consume lots of CPU cycles and operating system resources.

Stealth Virus:

It is a hidden computer virus, which specifically attacks operating system processes. It usually hides itself in partitions, files or boot sectors and is capable of going unnoticed during antivirus or anti-malware scans, i.e., it can avoid detection intentionally.

Symptoms of a Computer Virus:

There are many warning signs or symptoms which show that a computer is infected with a virus, some of which are as follows:

  • Slow computer performance: The machine may work slowly, e.g., it will take more time to open or shut down the computer or while opening a file, document, computer application, etc. The operating system and internet speed may get slow.
  • Frequent pop-ups: A virus may cause unusual frequent pop-ups on your window.
  • Hard Drive issue: The hard drive may exhibit unusual high activity even when it is not in use. It may cause unwanted changes to your hard drive and may freeze or crash this device.
  • Frequent crashes: One may experience frequent sudden system crashes while playing games, watching videos, or doing some other work using the infected system. A blue screen appears when it crashes.
  • Unknown programs: Unwanted programs may open or start automatically when you start your computer. You can see these programs in your computer’s list of active applications. Sometimes, the window shuts down unexpectedly without any reason.
  • Unusual activities: Your machine may perform differently, such as you may not be able to log into your accounts, to delete the corrupt files, and Blue Screen of Death (BSOD) may appear frequently, and more. Furthermore, the hardware, software, or OS may start malfunctioning leading to crashing the system abruptly.
  • Impaired security solutions: Sometimes, security measures taken by you, such as antivirus may not work smoothly due to virus attack on your computer.
  • Network issue: Sometimes, you experience high network activity even if you are not connected to the internet and vice versa.
  • Unnecessary advertisement: We often see advertisements while browsing, but if you see them even when you are not browsing, it may indicate a virus on your computer.
  • Display problems: You may experience different colors in your display if your computer is affected by a virus.
  • Affected Applications: Some viruses are developed to affect specific applications. Consequently, some applications may not work on your computer if it is infected.
  • Blocked by Antivirus Sites: An antivirus site may deny access to a computer that is infected by a virus.
  • Dialog Boxes: Many dialog boxes keep appearing suddenly on your screen.
  • Printer Issues: A printer attached to an infected computer may print documents without getting any command or in an inappropriate manner.
  • Changed Homepage: Your home page may get changed without any effort from your side. For example, you may see a new toolbar on your screen, and you may be redirected to a different web address instead of the page visited by you initially.
  • Strange messages: One may see strange messages on a computer screen such as error messages, e.g., “cannot rename “folder” as a folder already exists with this name”
Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 9: Data and Information OS and Network

by | Jan 6, 2022 | Computer Fundamentals

Data can be defined as a representation of facts, concepts, or instructions in a formalized manner, which should be suitable for communication, interpretation, or processing by human or electronic machine.

Data is represented with the help of characters such as alphabets (A-Z, a-z), digits (0-9) or special characters (+,-,/,*,<,>,= etc.)

What is Information?

Information is organized or classified data, which has some meaningful values for the receiver. Information is the processed data on which decisions and actions are based.

For the decision to be meaningful, the processed data must qualify for the following characteristics −

  • Timely − Information should be available when required.
  • Accuracy − Information should be accurate.
  • Completeness − Information should be complete.

Data Processing Cycle

Data processing is the re-structuring or re-ordering of data by people or machine to increase their usefulness and add values for a particular purpose. Data processing consists of the following basic steps – input, processing, and output. These three steps constitute the data processing cycle.

  • Input − In this step, the input data is prepared in some convenient form for processing. The form will depend on the processing machine. For example, when electronic computers are used, the input data can be recorded on any one of the several types of input medium, such as magnetic disks, tapes, and so on.
  • Processing − In this step, the input data is changed to produce data in a more useful form. For example, pay-checks can be calculated from the time cards, or a summary of sales for the month can be calculated from the sales orders.
  • Output − At this stage, the result of the proceeding processing step is collected. The particular form of the output data depends on the use of the data. For example, output data may be pay-checks for employees.

A computer network is a system in which multiple computers are connected to each other to share information and resources.

Computer Networks

Characteristics of a Computer Network

  • Share resources from one computer to another.
  • Create files and store them in one computer, access those files from the other computer(s) connected over the network.
  • Connect a printer, scanner, or a fax machine to one computer within the network and let other computers of the network use the machines available over the network.

Following is the list of hardware’s required to set up a computer network.

  • Network Cables
  • Distributors
  • Routers
  • Internal Network Cards
  • External Network Cards

Network Cables

Network cables are used to connect computers. The most commonly used cable is Category 5 cable RJ-45.

Network Cables

Distributors

A computer can be connected to another one via a serial port but if we need to connect many computers to produce a network, this serial connection will not work.

Network Distributors

The solution is to use a central body to which other computers, printers, scanners, etc. can be connected and then this body will manage or distribute network traffic.

Router

A router is a type of device which acts as the central point among computers and other devices that are a part of the network. It is equipped with holes called ports. Computers and other devices are connected to a router using network cables. Now-a-days router comes in wireless modes using which computers can be connected without any physical cable.

Network Router

Network Card

Network card is a necessary component of a computer without which a computer cannot be connected over a network. It is also known as the network adapter or Network Interface Card (NIC). Most branded computers have network card pre-installed. Network cards are of two types: Internal and External Network Cards.

Internal Network Cards

Motherboard has a slot for internal network card where it is to be inserted. Internal network cards are of two types in which the first type uses Peripheral Component Interconnect (PCI) connection, while the second type uses Industry Standard Architecture (ISA). Network cables are required to provide network access.

Network Card

External Network Cards

External network cards are of two types: Wireless and USB based. Wireless network card needs to be inserted into the motherboard, however no network cable is required to connect to the network.

External Network Card

Universal Serial Bus (USB)

USB card is easy to use and connects via USB port. Computers automatically detect USB card and can install the drivers required to support the USB network card automatically.

Data Card

The Operating System is a program with the following features −

  • An operating system is a program that acts as an interface between the software and the computer hardware.
  • It is an integrated set of specialized programs used to manage overall resources and operations of the computer.
  • It is a specialized software that controls and monitors the execution of all other programs that reside in the computer, including application programs and other system software.

Operating System

Objectives of Operating System

The objectives of the operating system are −

  • To make the computer system convenient to use in an efficient manner.
  • To hide the details of the hardware resources from the users.
  • To provide users a convenient interface to use the computer system.
  • To act as an intermediary between the hardware and its users, making it easier for the users to access and use other resources.
  • To manage the resources of a computer system.
  • To keep track of who is using which resource, granting resource requests, and mediating conflicting requests from different programs and users.
  • To provide efficient and fair sharing of resources among users and programs.

Characteristics of Operating System

Here is a list of some of the most prominent characteristic features of Operating Systems −

  • Memory Management − Keeps track of the primary memory, i.e. what part of it is in use by whom, what part is not in use, etc. and allocates the memory when a process or program requests it.
  • Processor Management − Allocates the processor (CPU) to a process and deallocates the processor when it is no longer required.
  • Device Management − Keeps track of all the devices. This is also called I/O controller that decides which process gets the device, when, and for how much time.
  • File Management − Allocates and de-allocates the resources and decides who gets the resources.
  • Security − Prevents unauthorized access to programs and data by means of passwords and other similar techniques.
  • Job Accounting − Keeps track of time and resources used by various jobs and/or users.
  • Control Over System Performance − Records delays between the request for a service and from the system.
  • Interaction with the Operators − Interaction may take place via the console of the computer in the form of instructions. The Operating System acknowledges the same, does the corresponding action, and informs the operation by a display screen.
  • Error-detecting Aids − Production of dumps, traces, error messages, and other debugging and error-detecting methods.
  • Coordination Between Other Software and Users − Coordination and assignment of compilers, interpreters, assemblers, and other software to the various users of the computer systems.
Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 8: Computer Fundamentals Number System

by | Jan 6, 2022 | Computer Fundamentals

Number System

When we type some letters or words, the computer translates them in numbers as computers can understand only numbers. A computer can understand the positional number system where there are only a few symbols called digits and these symbols represent different values depending on the position they occupy in the number.

The value of each digit in a number can be determined using −

  • The digit
  • The position of the digit in the number
  • The base of the number system (where the base is defined as the total number of digits available in the number system)

Decimal Number System

The number system that we use in our day-to-day life is the decimal number system. Decimal number system has base 10 as it uses 10 digits from 0 to 9. In decimal number system, the successive positions to the left of the decimal point represent units, tens, hundreds, thousands, and so on.

Each position represents a specific power of the base (10). For example, the decimal number 1234 consists of the digit 4 in the units position, 3 in the tens position, 2 in the hundreds position, and 1 in the thousands position. Its value can be written as

(1 x 1000)+ (2 x 100)+ (3 x 10)+ (4 x l)
(1 x 10

3

)+ (2 x 10

2

)+ (3 x 10

1

)+ (4 x l0

0

)
1000 + 200 + 30 + 4
1234

As a computer programmer or an IT professional, you should understand the following number systems which are frequently used in computers.

S.No. Number System and Description
1 Binary Number System

Base 2. Digits used : 0, 1
2 Octal Number System

Base 8. Digits used : 0 to 7
3 Hexa Decimal Number System

Base 16. Digits used: 0 to 9, Letters used : A- F

Binary Number System

Characteristics of the binary number system are as follows −

  • Uses two digits, 0 and 1
  • Also called as base 2 number system
  • Each position in a binary number represents a 0 power of the base (2). Example 20
  • Last position in a binary number represents a x power of the base (2). Example 2x where x represents the last position – 1.

Example

Binary Number: 101012

Calculating Decimal Equivalent −

Step Binary Number Decimal Number
Step 1 101012 ((1 x 24) + (0 x 23) + (1 x 22) + (0 x 21) + (1 x 20))10
Step 2 101012 (16 + 0 + 4 + 0 + 1)10
Step 3 101012 2110

Note − 101012 is normally written as 10101.

Octal Number System

Characteristics of the octal number system are as follows −

  • Uses eight digits, 0,1,2,3,4,5,6,7
  • Also called as base 8 number system
  • Each position in an octal number represents a 0 power of the base (8). Example 80
  • Last position in an octal number represents a x power of the base (8). Example 8x where x represents the last position – 1

Example

Octal Number: 125708

Calculating Decimal Equivalent −

Step Octal Number Decimal Number
Step 1 125708 ((1 x 84) + (2 x 83) + (5 x 82) + (7 x 81) + (0 x 80))10
Step 2 125708 (4096 + 1024 + 320 + 56 + 0)10
Step 3 125708 549610

Note − 125708 is normally written as 12570.

Hexadecimal Number System

Characteristics of hexadecimal number system are as follows −

  • Uses 10 digits and 6 letters, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F
  • Letters represent the numbers starting from 10. A = 10. B = 11, C = 12, D = 13, E = 14, F = 15
  • Also called as base 16 number system
  • Each position in a hexadecimal number represents a 0 power of the base (16). Example, 160
  • Last position in a hexadecimal number represents a x power of the base (16). Example 16x where x represents the last position – 1

Example

Hexadecimal Number: 19FDE16

Calculating Decimal Equivalent −

Step Binary Number Decimal Number
Step 1 19FDE16 ((1 x 164) + (9 x 163) + (F x 162) + (D x 161) + (E x 160))10
Step 2 19FDE16 ((1 x 164) + (9 x 163) + (15 x 162) + (13 x 161) + (14 x 160))10
Step 3 19FDE16 (65536+ 36864 + 3840 + 208 + 14)10
Step 4 19FDE16 10646210

Note − 19FDE16 is normally written as 19FDE.

Number Conversion

There are many methods or techniques which can be used to convert numbers from one base to another. In this chapter, we’ll demonstrate the following −

  • Decimal to Other Base System
  • Other Base System to Decimal
  • Other Base System to Non-Decimal
  • Shortcut method – Binary to Octal
  • Shortcut method – Octal to Binary
  • Shortcut method – Binary to Hexadecimal
  • Shortcut method – Hexadecimal to Binary

Decimal to Other Base System

Step 1 − Divide the decimal number to be converted by the value of the new base.

Step 2 − Get the remainder from Step 1 as the rightmost digit (least significant digit) of the new base number.

Step 3 − Divide the quotient of the previous divide by the new base.

Step 4 − Record the remainder from Step 3 as the next digit (to the left) of the new base number.

Repeat Steps 3 and 4, getting remainders from right to left, until the quotient becomes zero in Step 3.

The last remainder thus obtained will be the Most Significant Digit (MSD) of the new base number.

Example

Decimal Number: 2910

Calculating Binary Equivalent −

Step Operation Result Remainder
Step 1 29 / 2 14 1
Step 2 14 / 2 7 0
Step 3 7 / 2 3 1
Step 4 3 / 2 1 1
Step 5 1 / 2 0 1

As mentioned in Steps 2 and 4, the remainders have to be arranged in the reverse order so that the first remainder becomes the Least Significant Digit (LSD) and the last remainder becomes the Most Significant Digit (MSD).

Decimal Number : 2910 = Binary Number : 111012.

Other Base System to Decimal System

Step 1 − Determine the column (positional) value of each digit (this depends on the position of the digit and the base of the number system).

Step 2 − Multiply the obtained column values (in Step 1) by the digits in the corresponding columns.

Step 3 − Sum the products calculated in Step 2. The total is the equivalent value in decimal.

Example

Binary Number: 111012

Calculating Decimal Equivalent −

Step Binary Number Decimal Number
Step 1 111012 ((1 x 24) + (1 x 23) + (1 x 22) + (0 x 21) + (1 x 20))10
Step 2 111012 (16 + 8 + 4 + 0 + 1)10
Step 3 111012 2910

Binary Number : 111012 = Decimal Number : 2910

Other Base System to Non-Decimal System

Step 1 − Convert the original number to a decimal number (base 10).

Step 2 − Convert the decimal number so obtained to the new base number.

Example

Octal Number : 258

Calculating Binary Equivalent −

Step 1 – Convert to Decimal

Step Octal Number Decimal Number
Step 1 258 ((2 x 81) + (5 x 80))10
Step 2 258 (16 + 5)10
Step 3 258 2110

Octal Number : 258 = Decimal Number : 2110

Step 2 – Convert Decimal to Binary

Step Operation Result Remainder
Step 1 21 / 2 10 1
Step 2 10 / 2 5 0
Step 3 5 / 2 2 1
Step 4 2 / 2 1 0
Step 5 1 / 2 0 1

Decimal Number : 2110 = Binary Number : 101012

Octal Number : 258 = Binary Number : 101012

Shortcut Method ─ Binary to Octal

Step 1 − Divide the binary digits into groups of three (starting from the right).

Step 2 − Convert each group of three binary digits to one octal digit.

Example

Binary Number : 101012

Calculating Octal Equivalent −

Step Binary Number Octal Number
Step 1 101012 010 101
Step 2 101012 28 58
Step 3 101012 258

Binary Number : 101012 = Octal Number : 258

Shortcut Method ─ Octal to Binary

Step 1 − Convert each octal digit to a 3-digit binary number (the octal digits may be treated as decimal for this conversion).

Step 2 − Combine all the resulting binary groups (of 3 digits each) into a single binary number.

Example

Octal Number : 258

Calculating Binary Equivalent −

Step Octal Number Binary Number
Step 1 258 210 510
Step 2 258 0102 1012
Step 3 258 0101012

Octal Number : 258 = Binary Number : 101012

Shortcut Method ─ Binary to Hexadecimal

Step 1 − Divide the binary digits into groups of four (starting from the right).

Step 2 − Convert each group of four binary digits to one hexadecimal symbol.

Example

Binary Number : 101012

Calculating hexadecimal Equivalent −

Step Binary Number Hexadecimal Number
Step 1 101012 0001 0101
Step 2 101012 110 510
Step 3 101012 1516

Binary Number : 101012 = Hexadecimal Number : 1516

Shortcut Method – Hexadecimal to Binary

Step 1 − Convert each hexadecimal digit to a 4-digit binary number (the hexadecimal digits may be treated as decimal for this conversion).

Step 2 − Combine all the resulting binary groups (of 4 digits each) into a single binary number.

Example

Hexadecimal Number : 1516

Calculating Binary Equivalent −

Step Hexadecimal Number Binary Number
Step 1 1516 110 510
Step 2 1516 00012 01012
Step 3 1516 000101012

Hexadecimal Number : 1516 = Binary Number : 101012

Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 7: Computer Fundamentals Software

by | Jan 6, 2022 | Computer Fundamentals

Software

Software, which is abbreviated as SW or S/W, is a set of programs that enables the hardware to perform a specific task. All the programs that run the computer are software. The software can be of three types: system software, application software, and programming software.

1) System Software

The system software is the main software that runs the computer. When you turn on the computer, it activates the hardware and controls and coordinates their functioning. The application programs are also controlled by system software. An operating system is an example of system software.

Here is a list of some of the most prominent features of a system software −

  • Close to the system
  • Fast in speed
  • Difficult to design
  • Difficult to understand
  • Less interactive
  • Smaller in size
  • Difficult to manipulate
  • Generally written in low-level language

i) Operating System:

An operating system is the system software that works as an interface to enable the user to communicate with the computer. It manages and coordinates the functioning of hardware and software of the computer. The commonly used operating systems are Microsoft Windows, Linux, and Apple Mac OS X.

Some other examples of system software include:

  • BIOS: It stands for basic input output system. It is a type of system software, which is stored in Read Only Memory (ROM) located on the motherboard. However, in advanced computer systems, it is stored in flash memory. BIOS is the first software that gets activated when you turn on your computer system. It loads the drivers of the hard disk into memory as well as assists the operating system to load itself into the memory.
  • Boot Program: Boot refers to starting up a computer. When you switch on the computer, the commands in the ROM are executed automatically to load the boot program into memory and execute its instructions. The BIOS program has a basic set of commands that enables the computer to perform the basic input/output instructions to start the computer.
  • An assembler: It plays the role of a converter as it receives basic computer instructions and converts them into a pattern of bits. The processor uses these bits to perform basic operations.
  • A device driver: This system software controls hardware devices connected to a computer. It enables the computer to use the hardware by providing an appropriate interface. The kernel of a Computer’s CPU communicates with different hardware through this software. Operating systems generally come with most of the device drivers. If the operating system does not have a device driver for hardware, you have to install the device driver before using that hardware device.

2) Application Software:

Application software is a set of programs designed to perform a specific task. It does not control the working of a computer as it is designed for end-users. A computer can run without application software. Application software can be easily installed or uninstalled as required. It can be a single program or a collection of small programs. Microsoft Office Suite, Adobe Photoshop, and any other software like payroll software or income tax software are application software.

Examples of Application software are the following −

  • Payroll Software
  • Student Record Software
  • Inventory Management Software
  • Income Tax Software
  • Railways Reservation Software
  • Microsoft Office Suite Software
  • Microsoft Word
  • Microsoft Excel
  • Microsoft PowerPoint

As we know, they are designed to perform specific tasks. Accordingly, they can be of different types such as:

  • Word Processing Software: This software allows users to create, edit, format, and manipulate the text and more. It offers lots of options for writing documents, creating images, and more. For example, MS Word, WordPad, Notepad, etc.
  • Spreadsheet Software: It is designed to perform calculations, store data, create charts, etc. It has rows and columns, and the data is entered in the cell, which is an intersection of a row and column, e.g., Microsoft Excel.
  • Multimedia Software: These software are developed to perform editing of video, audio, and text. It allows you to combine texts, videos, audio, and images. Thus, you can improve a text document by adding photos, animations, graphics, and charts through multimedia software. For example, VLC player, Window Media Player, etc.
  • Enterprise Software: These software are developed for business operational functions. It is used in large organizations where the quantum of business is too large. It can be used for accounting, billing, order processing and more. For example, CRM (Customer Relationship Management), BI (Business Intelligence), ERP (Enterprise Resource Planning), SCM (Supply Chain Management), customer support system, and more.

Features of application software are as follows −

  • Close to the user
  • Easy to design
  • More interactive
  • Slow in speed
  • Generally written in high-level language
  • Easy to understand
  • Easy to manipulate and use
  • Bigger in size and requires large storage space

3) Programming Software:

It is a set or collection of tools that help developers in writing other software or programs. It assists them in creating, debugging, and maintaining software or programs or applications. We can say that these are facilitator software that helps translate programming language such as Java, C++, Python, etc., into machine language code. So, it is not used by end-users. For example, compilers, linkers, debuggers, interpreters, text editors, etc. This software is also called a programming tool or software development tool.

Some examples of programming software include:

  • Eclipse: It is a java language editor.
  • Coda: It is a programming language editor for Mac.
  • Notepad++: It is an open-source editor for windows.
  • Sublime text: It is a cross-platform code editor for Linux, Mac, and Windows.
Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 6: Computer Fundamentals Memory

by | Jan 6, 2022 | Computer Fundamentals

Computer Fundamentals Memory

A memory is just like a human brain. It is used to store data and instructions. Computer memory is the storage space in the computer, where data is to be processed and instructions required for processing are stored. The memory is divided into large number of small parts called cells. Each location or cell has a unique address, which varies from zero to memory size minus one. For example, if the computer has 64k words, then this memory unit has 64 * 1024 = 65536 memory locations. The address of these locations varies from 0 to 65535.

Memory is primarily of three types −

  • Cache Memory
  • Primary Memory/Main Memory
  • Secondary Memory

Cache Memory

Cache memory is a very high speed semiconductor memory which can speed up the CPU. It acts as a buffer between the CPU and the main memory. It is used to hold those parts of data and program which are most frequently used by the CPU. The parts of data and programs are transferred from the disk to cache memory by the operating system, from where the CPU can access them.

Cache Memory

Advantages

The advantages of cache memory are as follows −

  • Cache memory is faster than main memory.
  • It consumes less access time as compared to main memory.
  • It stores the program that can be executed within a short period of time.
  • It stores data for temporary use.

Disadvantages

The disadvantages of cache memory are as follows −

  • Cache memory has limited capacity.
  • It is very expensive.

Primary Memory (Main Memory)

Primary memory holds only those data and instructions on which the computer is currently working. It has a limited capacity and data is lost when power is switched off. It is generally made up of semiconductor device. These memories are not as fast as registers. The data and instruction required to be processed resides in the main memory. It is divided into two subcategories RAM and ROM.

Primary Memory

Characteristics of Main Memory

  • These are semiconductor memories.
  • It is known as the main memory.
  • Usually volatile memory.
  • Data is lost in case power is switched off.
  • It is the working memory of the computer.
  • Faster than secondary memories.
  • A computer cannot run without the primary memory.

Secondary Memory

This type of memory is also known as external memory or non-volatile. It is slower than the main memory. These are used for storing data/information permanently. CPU directly does not access these memories, instead they are accessed via input-output routines. The contents of secondary memories are first transferred to the main memory, and then the CPU can access it. For example, disk, CD-ROM, DVD, etc.

Secondar Memory

Characteristics of Secondary Memory

  • These are magnetic and optical memories.
  • It is known as the backup memory.
  • It is a non-volatile memory.
  • Data is permanently stored even if power is switched off.
  • It is used for storage of data in a computer.
  • Computer may run without the secondary memory.
  • Slower than primary memories.

What is a hardware upgrade?

A hardware upgrade refers to a new hardware, or a replacement for the old one, or additional hardware developed to improve the performance of the existing hardware. A common example of a hardware upgrade is a RAM upgrade that increases the computer’s total memory, and video card upgrade, where the old video card is removed and replaced with the new one.

Some of the commonly used hardware in your computer are described below:

1) Motherboard:

The motherboard is generally a thin circuit board that holds together almost all parts of a computer except input and output devices. All crucial hardware like CPU, memory, hard drive, and ports for input and output devices are located on the motherboard. It is the biggest circuit board in a computer chassis.

It allocates power to all hardware located on it and enables them to communicate with each other. It is meant to hold the computer’s microprocessor chip and let other components connect to it. Each component that runs the computer or improves its performance is a part of the motherboard or connected to it through a slot or port.

There can be different types of motherboards based on the type and size of the computers. So, a specific motherboard can work only with specific types of processors and memory.

Components of a Motherboard:

CPU Slot: It is provided to install the CPU. It is a link between a microprocessor and a motherboard. It facilitates the use of CPU and prevents the damage when it is installed or removed. Furthermore, it is provided with a lock to prevent CPU movement and a heat sink to dissipate the extra heat.

RAM Slot: It is a memory slot or socket provided in the motherboard to insert or install the RAM (Random Access Memory). There can be two or more memory slots in a computer.

Expansion Slot: It is also called the bus slot or expansion port. It is a connection or port on the motherboard, which provides an installation point to connect a hardware expansion card, for example, you can purchase a video expansion card and install it into the expansion slot and then can install a new video card in the computer. Some of the common expansion slots in a computer are AGP, AMR, CNR, PCI, etc.

Capacitor: It is made of two conductive plates, and a thin insulator sandwiched between them. These parts are wrapped in a plastic container.

Inductor (Coil): It is an electromagnetic coil made of a conducting wire wrapped around an iron core. It acts as an inductor or electromagnet to store magnetic energy.

Northbridge: It is an integrated circuit that allows communications between the CPU interface, AGP, and memory. Furthermore, it also allows the southbridge chip to communicate with the RAM, CPU, and graphics controller.

USB Port: It allows you to connect hardware devices like mouse, keyboard to your computer.

PCI Slot: It stands for Peripheral Component Interconnect slot. It allows you to connect the PCI devices like modems, network hardware, sound, and video cards.

AGP Slot: It stands for Accelerated Graphics Port. It provides the slot to connect graphics cards.

Heat Sink: It absorbs and disperses the heat generated in the computer processor.

Power Connector: It is designed to supply power to the motherboard.

CMOS battery: It stands for complementary metal-oxide-semiconductor. It is a memory that stores the BIOS settings such as time, date, and hardware settings.

2) Monitor:

A monitor is the display unit of a computer on which the processed data, such as text, images, etc., is displayed. It comprises a screen circuity and the case which encloses this circuity. The monitor is also known as a visual display unit (VDU).

Types of Monitors:

  1. CRT Monitor: It has cathode ray tubes which produce images in the form of video signals. Its main components are electron gun assembly, deflection plate assembly, glass envelope, fluorescent screen, and base.
  2. LCD Monitor: It is a flat panel screen. It uses liquid crystal display technology to produce images on the screen. Advanced LEDs have thin-film transistors with capacitors and use active-matrix technology, which allows pixels to retain their charge.
  3. LED Monitor: It is an advanced version of an LCD monitor. Unlike an LCD monitor, which uses cold cathode fluorescent light to backlight the display, it has LED panels, each of which has lots of LEDs to display the backlight.
  4. Plasma Monitor: It uses plasma display technology that allows it to produce high resolutions of up to 1920 X 1080, wide viewing angle, a high refresh rate, outstanding contrast ration, and more.

3) Keyboard:

It is the most important input device of a computer. It is designed to allow you input text, characters, and other commands into a computer, desktop, tablet, etc. It comes with different sets of keys to enter numbers, characters, and perform various other functions like copy, paste, delete, enter, etc.

Types of Keyboards:

  1. QWERTY Keyboards
  2. AZERTY Keyboards
  3. DVORAK Keyboards

4) Mouse:

It is a small handheld device designed to control or move the pointer (computer screen’s cursor) in a GUI (graphical user interface). It allows you to point to or select objects on a computer’s display screen. It is generally placed on a flat surface as we need to move it smoothly to control the pointer. Types of Mouse: Trackball mouse, Mechanical Mouse, Optical Mouse, Wireless Mouse, etc.

Main functions of a mouse:

  • Move the cursor: It is the main function of the mouse; to move the cursor on the screen.
  • Open or execute a program: It allows you to open a folder or document and execute a program. You are required to take the cursor on the folder and double click it to open it.
  • Select: It allows you to select text, file, or any other object.
  • Hovering: Hovering is an act of moving the mouse cursor over a clickable object. During hovering over an object, it displays information about the object without pressing any button of the mouse.
  • Scroll: It allows you to scroll up or down while viewing a long webpage or document.

Parts of a mouse:

  • Two buttons: A mouse is provided with two buttons for right click and left click.
  • Scroll Wheel: A wheel located between the right and left buttons, which is used to scroll up and down and Zoom in and Zoom out in some applications like AutoCAD.
  • Battery: A battery is required in a wireless mouse.
  • Motion Detection Assembly: A mouse can have a trackball or an optical sensor to provide signals to the computer about the motion and location of the mouse.
Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 5: Computer Fundamentals CPU(Central Processing Unit)

by | Jan 6, 2022 | Computer Fundamentals

Central Processing Unit (CPU) consists of the following features −

  • CPU is considered as the brain of the computer.
  • CPU performs all types of data processing operations.
  • It stores data, intermediate results, and instructions (program).
  • It controls the operation of all parts of the computer.

CPU

CPU itself has following three components.

  • Memory or Storage Unit
  • Control Unit
  • ALU(Arithmetic Logic Unit)

Computer Architectures

Memory or Storage Unit

This unit can store instructions, data, and intermediate results. This unit supplies information to other units of the computer when needed. It is also known as internal storage unit or the main memory or the primary storage or Random Access Memory (RAM).

Its size affects speed, power, and capability. Primary memory and secondary memory are two types of memories in the computer. Functions of the memory unit are −

  • It stores all the data and the instructions required for processing.
  • It stores intermediate results of processing.
  • It stores the final results of processing before these results are released to an output device.
  • All inputs and outputs are transmitted through the main memory.

Control Unit

This unit controls the operations of all parts of the computer but does not carry out any actual data processing operations.

Functions of this unit are −

  • It is responsible for controlling the transfer of data and instructions among other units of a computer.
  • It manages and coordinates all the units of the computer.
  • It obtains the instructions from the memory, interprets them, and directs the operation of the computer.
  • It communicates with Input/Output devices for transfer of data or results from storage.
  • It does not process or store data.

ALU (Arithmetic Logic Unit)

This unit consists of two subsections namely,

  • Arithmetic Section
  • Logic Section

Arithmetic Section

Function of arithmetic section is to perform arithmetic operations like addition, subtraction, multiplication, and division. All complex operations are done by making repetitive use of the above operations.

Logic Section

Function of logic section is to perform logic operations such as comparing, selecting, matching, and merging of data.

What is CPU Clock Speed?

The clock speed of a CPU or a processor refers to the number of instructions it can process in a second. It is measured in gigahertz. For example, a CPU with a clock speed of 4.0 GHz means it can process 4 billion instructions in a second.

Types of CPU:

CPUs are mostly manufactured by Intel and AMD, each of which manufactures its own types of CPUs. In modern times, there are lots of CPU types in the market. Some of the basic types of CPUs are described below:

Single Core CPU: Single Core is the oldest type of computer CPU, which was used in the 1970s. It has only one core to process different operations. It can start only one operation at a time; the CPU switches back and forth between different sets of data streams when more than one program runs. So, it is not suitable for multitasking as the performance will be reduced if more than one application runs. The performance of these CPUs is mainly dependent on the clock speed. It is still used in various devices, such as smartphones.

Dual Core CPU: As the name suggests, Dual Core CPU contains two cores in a single Integrated Circuit (IC). Although each core has its own controller and cache, they are linked together to work as a single unit and thus can perform faster than the single-core processors and can handle multitasking more efficiently than Single Core processors.

Quad Core CPU: This type of CPU comes with two dual-core processors in one integrated circuit (IC) or chip. So, a quad-core processor is a chip that contains four independent units called cores. These cores read and execute instructions of CPU. The cores can run multiple instructions simultaneously, thereby increases the overall speed for programs that are compatible with parallel processing.

Quad Core CPU uses a technology that allows four independent processing units (cores) to run in parallel on a single chip. Thus by integrating multiple cores in a single CPU, higher performance can be generated without boosting the clock speed. However, the performance increases only when the computer’s software supports multiprocessing. The software which supports multiprocessing divides the processing load between multiple processors instead of using one processor at a time.

History of CPU:

Some of the important events in the development of CPU since its invention till date are as follows:

  • In 1823, Baron Jons Jackob Berzelius discovered silicon that is the main component of CPU till date.
  • In 1903, Nikola Tesla got gates or switches patented, which are electrical logic circuits.
  • In December 1947, John Bardeen, William Shockley, and Walter Brattain invented the first transistor at the Bell Laboratories and got it patented in 1948.
  • In 1958, the first working integrated circuit was developed by Robert Noyce and Jack Kilby.
  • In 1960, IBM established the first mass-production facility for transistors in New York.
  • In 1968, Robert Noyce and Gordon Moore founded Intel Corporation.
  • AMD (Advanced Micro Devices) was founded in May 1969.
  • In 1971, Intel introduced the first microprocessor, the Intel 4004, with the help of Ted Hoff.
  • In 1972, Intel introduced the 8008 processor; in 1976, Intel 8086 was introduced, and in June 1979, Intel 8088 was released.
  • In 1979, a 16/32-bit processor, the Motorola 68000, was released. Later, it was used as a processor for the Apple Macintosh and Amiga computers.
  • In 1987, Sun introduced the SPARC processor.
  • In March 1991, AMD introduced the AM386 microprocessor family.
  • In March 1993, Intel released the Pentium processor. In 1995, Cyrix introduced the Cx5x86 processor to give competition to Intel Pentium processors.
  • In January 1999, Intel introduced the Celeron 366 MHz and 400 MHz processors.
  • In April 2005, AMD introduced its first dual-core processor.
  • In 2006, Intel introduced the Core 2 Duo processor.
  • In 2007, Intel introduced different types of Core 2 Quad processors.
  • In April 2008, Intel introduced the first series of Intel Atom processors, the Z5xx series. They were single-core processors with a 200 MHz GPU.
  • In September 2009, Intel released the first Core i5 desktop processor with four cores.
  • In January 2010, Intel released many processors such as Core 2 Quad processor Q9500, first Core i3 and i5 mobile processors, first Core i3 and i5 desktop processors. In the same year in July, it released the first Core i7 desktop processor with six cores.
  • In June 2017, Intel introduced the first Core i9 desktop processor.
  • In April 2018, Intel released the first Core i9 mobile processor.
Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 4: Computer Fundamentals Output Components

by | Jan 6, 2022 | Computer Fundamentals

Output Devices

The output device displays the result of the processing of raw data that is entered in the computer through an input device. There are a number of output devices that display output in different ways such as text, images, hard copies, and audio or video.

Some of the popular output devices are:

  1. Monitor
    • CRT Monitor
    • LCD Monitor
    • LED Monitor
    • Plasma Monitor
  2. Printer
    • Impact Printers
      1. Character Printers
        1. Dot Matrix printers
        2. Daisy Wheel printers
      2. Line printers
        1. Drum printers
        2. Chain printers
    • Non-impact printers
      1. Laser printers
      2. Inkjet printers
  3. Projector

1) Monitor

The monitor is the display unit or screen of the computer. It is the main output device that displays the processed data or information as text, images, audio or video.

The types of monitors are given below.

i) CRT Monitor

CRT Monitor

CRT monitors are based on the cathode ray tubes. They are like vacuum tubes which produce images in the form of video signals. Cathode rays tube produces a beam of electrons through electron guns that strike on the inner phosphorescent surface of the screen to produce images on the screen. The monitor contains millions of phosphorus dots of red, green and blue color. These dots start to glow when struck by electron beams and this phenomenon is called cathodoluminescence.

The main components of a CRT monitor include the electron gun assembly, deflection plate assembly, fluorescent screen, glass envelope, and base.The front (outer surface) of the screen onto which images are produced is called the face plate. It is made up of fiber optics.

There are three electron beams that strike the screen: red, green, and blue. So, the colors which you see on the screen are the blends of red, blue and green lights.The magnetic field guides the beams of electrons. Although LCDs have replaced the CRT monitors, the CRT monitors are still used by graphics professionals because of their color quality.

ii) LCD Monitor

LCD Monitor

The LCD monitor is a flat panel screen that is compact and light-weight as compared to CRT monitors. It is based on liquid crystal display technology which is used in the screens of laptops, tablets, smart phones, etc. An LCD screen comprises two layers of polarized glass with a liquid crystal solution between them. When the light passes through the first layer, an electric current aligns the liquids crystals. The aligned liquid crystals allow a varying level of light to pass through the second layer to create images on the screen.

The LCD screen has a matrix of pixels that display the image on the screen.Old LCDs had passive-matrix screens in which individual pixels are controlled by sending a charge. A few electrical charges could be sent each second that made screens appear blurry when the images moved quickly on the screen.

Modern LCDs use active-matrix technology and contain thin film transistors (TFTs) with capacitors. This technology allows pixels to retain their charge. So, they don?t make screen blurry when images move fast on the screen as well as are more efficient than passive-matrix displays.

iii) LED monitor

LED Monitor

The LED monitor is an improved version of an LCD monitor. It also has a flat panel display and uses liquid crystal display technology like the LCD monitors. The difference between them lies in the source of light to backlight the display. The LED monitor has many LED panels, and each panel has several LEDsto backlight the display, whereas the LCD monitors use cold cathode fluorescent light to backlight the display.Modern electronic devices such as mobile phones, LED TVs, laptop and computer screens, etc., use a LED display as it not only produces more brilliance and greater light intensity but also consumes less power.

iv) Plasma Monitor

Plasma Monitor

The plasma monitor is also a flat panel display that is based on plasma display technology. It has small tiny cells between two glass panels. These cells contain mixtures of noble gases and a small amount of mercury. When voltage is applied, the gas in the cells turns into a plasma and emits ultraviolet light that creates images on the screen, i.e., the screen is illuminated by a tiny bit of plasma, a charged gas. Plasma displays are brighter than liquid crystal displays (LCD) and also offer a wide viewing angle than an LCD.

Plasma monitors provide high resolutions of up to 1920 X 1080, excellent contrast ratios, wide viewing angle, a high refresh rate and more. Thus, they offer a unique viewing experience while watching action movies, sports games, and more.

2) Printer

A printer produces hard copies of the processed data. It enables the user, to print images, text or any other information onto the paper.

Based on the printing mechanism, the printers are of two types: Impact Printers and Non-impact Printers.

  • Impact Printers: They are of two types:
    1. Character Printers
      1. Dot Matrix printers
      2. Daisy Wheel printers
    2. Line printers
      1. Drum printers
      2. Chain printers
  • Non-impact printers: They are of two types:
    1. Laser printers
    2. Inkjet printers

Impact Printer

The impact printer uses a hammer or print head to print the character or images onto the paper. The hammer or print head strikes or presses an ink ribbon against the paper to print characters and images.

Impact printers are further divided into two types.

  1. Character Printers
  2. Line printers

A) Character Printers

Character printer prints a single character at a time or with a single stroke of the print head or hammer. It does not print one line at a time. Dot Matrix printer and Daisy Wheel printer are character printers. Today, these printers are not in much use due to their low speed and because only the text can be printed. The character printers are of two types, which are as follows:

i) Dot Matrix Printer

Dot Matrix Printer

Dot Matrix Printer is an impact printer. The characters and images printed by it are the patterns of dots. These patterns are produced by striking the ink soaked ribbon against the paper with a print head. The print head contains pins that produce a pattern of dots on the paper to form the individual characters. The print head of a 24 pin dot matrix contains more pins than a 9 pin dot matrix printer, so it produces more dots which results in better printing of characters. To produce color output, the black ribbon can be changed with color stripes. The speed of Dot Matrix printers is around 200-500 characters per second.

ii) Daisy Wheel Printer

Daisy Wheel Printer

Daisy Wheel Printer was invented by David S. Lee at Diablo Data Systems.It consists of a wheel or disk that has spokes or extensions and looks like a daisy, so it is named Daisy Wheel printer. At the end of extensions, molded metal characters are mounted. To print a character the printer rotates the wheel, and when the desired character is on the print location the hammer hits disk and the extension hits the ink ribbon against the paper to create the impression. It cannot be used to print graphics and is often noisy and slow, i.e., the speed is very low around 25-50 characters per second. Due to these drawbacks,these printers have become obsolete.

B) Line Printers:

Line printer, which is also as a bar printer, prints one line at a time. It is a high-speed impact printer as it can print 500 to 3000 lines per minute. Drum printer and chain printer are examples of line printers.

i) Drum Printer:

Drum Printer

Drum printer is a line printer that is made of a rotating drum to print characters. The drum has circular bands of characters on its surface. It has a separate hammer for each band of characters. When you print, the drum rotates, and when the desired character comes under the hammer, the hammer strikes the ink ribbon against the paper to print characters. The drum rotates at a very high speed and characters are printed by activating the appropriate hammers. Although all the characters are not printed at a time, they are printed at a very high speed. Furthermore, it can print only a predefined style as it has a specific set of characters. These printers are known to be very noisy due to the use of hammering techniques.

ii) Chain Printer:

Chain Printer

Chain printer is a line printer that uses a rotating chain to print characters. The characters are embossed on the surface of the chain. The chain rotates horizontally around a set of hammers, for each print location one hammer is provided, i.e., the total number of hammers is equal to the total number of print positions.

The chain rotates at a very high speed and when the desired character comes at the print location, the corresponding hammer strikes the page against the ribbon and character on the chain.They can type 500 to 3000 lines per minute. They are also noisy due to the hammering action.

Non-Impact Printer:

Non-impact printers don’t print characters or images by striking a print head or hammer on the ink ribbon placed against the paper. They print characters and images without direct physical contact between the paper and the printing machinery. These printers can print a complete page at a time, so they are also known as page printers. The common types of non-impact printers are Laser printer and Inkjet printer:

i) Laser Printer:

Laser Printer

A laser printer is a non-impact printer that uses a laser beam to print the characters. The laser beam hits the drum, which is a photoreceptor and draws the image on the drum by altering electrical charges on the drum. The drum then rolls in toner, and the charged image on the drum picks the toner. The toner is then printed on the paper using heat and pressure. Once the document is printed, the drum loses the electric charge,and the remaining toner is collected. The laser printers use powdered toner for printing instead of liquid ink and produce quality print objects with a resolution of 600 dots per inch (dpi) or more.

ii) Inkjet Printer:

Inkjet Printer

The inkjet printer is a non-impact printer that prints images and characters by spraying fine,ionized drops of ink. The print head has tiny nozzles to spray the ink. The printer head moves back and forth and sprays ionized drops of ink on the paper, which is fed through the printer. These drops pass through an electric field that guides the ink onto the paper to print correct images and characters.

An inkjet printer has cartridges that contain ink. Modern inkjet printers are color printers that have four cartridges containing different colors: Cyan, Magenta, Yellow, and Black. It is capable of printing high-quality images with different colors. It can produce print objects with a resolution of at least 300 dots per inch (dpi).

3) Projector

Projector

A projector is an output device that enables the user to project the output onto a large surface such as a big screen or wall. It can be connected to a computer and similar devices to project their output onto a screen. It uses light and lenses to produce magnified texts, images, and videos. So, it is an ideal output device to give presentations or to teach a large number of people.

Modern projects (digital projectors) come with multiple input sources such as HDMI ports for newer equipment and VGA ports that support older devices. Some projectors are designed to support Wi-Fi and Bluetooth as well. They can be fixed onto the ceiling, placed on a stand, and more and are frequently used for classroom teaching, giving presentations, home cinemas, etc.

A digital projector can be of two types:

Liquid Crystal Display (LCD) digital projector: This type of digital projectors are very popular as they are lightweight and provide crisp output. An LCD projector uses transmissive technology to produce output. It allows the light source, which is a standard lamp, to pass through the three colored liquid crystal light panels. Some colors pass through the panels and some are blocked by the panels and thus images are on the screen.

Digital Light Processing (DLP) digital projector: It has a set of tiny mirrors, a separate mirror for each pixel of the image and thus provide high-quality images. These projectors are mostly used in theatres as they fulfill the requirement of high-quality video output.

Part 3: Computer Fundamentals Input Components

by | Jan 6, 2022 | Computer Fundamentals

Components

All types of computers follow the same basic logical structure and perform the following five basic operations for converting raw input data into information useful to their users.

S.No. Operation Description
1 Take Input The process of entering data and instructions into the computer system.
2 Store Data Saving data and instructions so that they are available for processing as and when required.
3 Processing Data Performing arithmetic, and logical operations on data in order to convert them into useful information.
4 Output Information The process of producing useful information or results for the user, such as a printed report or visual display.
5 Control the workflow Directs the manner and sequence in which all of the above operations are performed.

Computer Architectures

Input Unit

This unit contains devices with the help of which we enter data into the computer. This unit creates a link between the user and the computer. The input devices translate the information into a form understandable by the computer.

CPU (Central Processing Unit)

CPU is considered as the brain of the computer. CPU performs all types of data processing operations. It stores data, intermediate results, and instructions (program). It controls the operation of all parts of the computer.

CPU itself has the following three components −

  • ALU (Arithmetic Logic Unit)
  • Memory Unit
  • Control Unit

Output Unit

The output unit consists of devices with the help of which we get the information from the computer. This unit is a link between the computer and the users. Output devices translate the computer’s output into a form understandable by the users.

Input Devices

Input device enables the user to send data, information, or control signals to a computer. The Central Processing Unit (CPU) of a computer receives the input and processes it to produce the output.

Some of the popular input devices are:

  1. Keyboard
  2. Mouse
  3. Scanner
  4. Joystick
  5. Light Pen
  6. Digitizer
  7. Microphone
  8. Magnetic Ink Character Recognition (MICR)
  9. Optical Character Reader (OCR)
  10. Digital Camera
  11. Paddle
  12. Steering Wheel
  13. Gesture recognition devices
  14. Light Gun
  15. Touch Pad
  16. Remote
  17. Touch screen
  18. VR
  19. Webcam
  20. Biometric Devices

1) Keyboard

The keyboard is a basic input device that is used to enter data into a computer or any other electronic device by pressing keys. It has different sets of keys for letters, numbers, characters, and functions. Keyboards are connected to a computer through USB or a Bluetooth device for wireless communication.

Types of keyboards: There can be different types of keyboards based on the region and language used. Some of the common types of keyboards are as follows:

i) QWERTY Keyboard:

keyboard

It is the most commonly used keyboard with computers in modern times. It is named after the first six letters of the top row of buttons and is even popular in countries that do not use Latin-based alphabet. It is so popular that some people think that it is the only type of keyboard to use with computers as an input device.

ii) AZERTY Keyboard:

AZERTY keyboard

It is considered the standard French keyboard. It is developed in France as an alternative layout to the QWERTY layout and is mainly used in France and other European countries. Some countries have manufactured their own versions of AZERTY.

Its name is derived from the first six letters that appear on the top left row of the keyboard. The Q and W keys in AZERTY keyboard are interchanged with A and Z keys in QWERTY keyboard. Furthermore, in AZERTY keyboard M key is located to the left of the L key.

AZERTY keyboard differs from QWERTY keyboard not only in the placement of letters but also in many other ways, e.g., it gives emphasis on accents, which is required for writing European languages like French.

iii) DVORAK Keyboard:

DVORAK keyboard

This type of keyboard layout was developed to increase the typing speed by reducing the finger movement while typing. The most frequently used letters are kept in a home row to improve typing.

2) Mouse

The mouse is a hand-held input device which is used to move cursor or pointer across the screen. It is designed to be used on a flat surface and generally has left and right button and a scroll wheel between them. Laptop computers come with a touchpad that works as a mouse. It lets you control the movement of cursor or pointer by moving your finger over the touchpad. Some mouse comes with integrated features such as extra buttons to perform different buttons.

The mouse was invented by Douglas C. Engelbart in 1963. Early mouse had a roller ball integrated as a movement sensor underneath the device. Modern mouse devices come with optical technology that controls cursor movements by a visible or invisible light beam. A mouse is connected to a computer through different ports depending on the type of computer and type of a mouse.

Common types of the mouse:

i) Trackball Mouse:

Trackball mouse

It is a stationary input device that has ball mechanism to move the pointer or cursor on the screen. The ball is half inserted in the device and can be easily rolled with finger, thumb or the palm to move the pointer on the screen. The device has sensor to detect the rotation of ball. It remains stationary; you don’t need to move it on the operating surface. So, it is an ideal device if you have limited desk space as you don’t need to move it like a mouse.

ii) Mechanical Mouse:

Mechanical mouse

It has a system of a ball and several rollers to track its movement. It is a corded type of mouse. A mechanical mouse can be used for high performance. The drawback is that they tend to get dust into the mechanics and thus require regular cleaning.

iii) Optical Mouse:

Optical mouse

An optical mouse uses optical electronics to track its movement. It is more reliable than a mechanical mouse and also requires less maintenance. However, its performance is affected by the surface on which it is operated. Plain non-glossy mouse mat should be used for best results. The rough surface may cause problems for the optical recognition system, and the glossy surface may reflect the light wrongly and thus may cause tracking issues.

iv) Cordless or Wireless Mouse:

Cordless or Wireless mouse

As the name suggests, this type of mouse lacks cable and uses wireless technology such as IrDA (infrared) or radio (Bluetooth or Wi-Fi) to control the movement of the cursor. It is used to improve the experience of using a mouse. It uses batteries for its power supply.

3) Scanner

The scanner uses the pictures and pages of text as input. It scans the picture or a document. The scanned picture or document then converted into a digital format or file and is displayed on the screen as an output. It uses optical character recognition techniques to convert images into digital ones. Some of the common types of scanners are as follows:

Types of Scanner:

i) Flatbed Scanner:

Flatbed Scanner

It has a glass pane and a moving optical CIS or CCD array. The light illuminates the pane, and then the image is placed on the glass pane. The light moves across the glass pane and scans the document and thus produces its digital copy. You will need a transparency adapter while scanning transparent slides.

ii) Handheld Scanner:

Handheld Scanner

It is a small manual scanning device which is held by hand and is rolled over a flat image that is to be scanned. The drawback in using this device is that the hand should be steady while scanning; otherwise, it may distort the image. One of the commonly used handheld scanners is the barcode scanner which you would have seen in shopping stores.

iii) Sheetfed Scanner:

Sheetfed Scanner

In this scanner, the document is inserted into the slot provided in the scanner. The main components of this scanner include the sheet-feeder, scanning module, and calibration sheet. The light does not move in this scanner. Instead, the document moves through the scanner. It is suitable for scanning single page documents, not for thick objects like books, magazines, etc.

iv) Drum Scanner:

Drum Scanner

Drum scanner has a photomultiplier tube (PMT) to scan images. It does not have a charge-coupled device like a flatbed scanner. The photomultiplier tube is extremely sensitive to light. The image is placed on a glass tube, and the light moves across the image, which produces a reflection of the image which is captured by the PMT and processed. These scanners have high resolution and are suitable for detailed scans.

v) Photo Scanner:

Photo Scanner

It is designed to scan photographs. It has high resolution and color depth, which are required for scanning photographs. Some photo scanners come with in-built software for cleaning and restoring old photographs.

4) Joystick

Joystick

A joystick is also a pointing input device like a mouse. It is made up of a stick with a spherical base. The base is fitted in a socket that allows free movement of the stick. The movement of stick controls the cursor or pointer on the screen.

The frist joystick was invented by C. B. Mirick at the U.S. Naval Research Laboratory. A joystick can be of different types such as displacement joysticks, finger-operated joysticks, hand operated, isometric joystick, and more. In joystick, the cursor keeps moving in the direction of the joystick unless it is upright, whereas, in mouse, the cursor moves only when the mouse moves.

5) Light Pen

Light Pen

A light pen is a computer input device that looks like a pen. The tip of the light pen contains a light-sensitive detector that enables the user to point to or select objects on the display screen. Its light sensitive tip detects the object location and sends the corresponding signals to the CPU. It is not compatible with LCD screens, so it is not in use today. It also helps you draw on the screen if needed. The first light pen was invented around 1955 as a part of the Whirlwind project at the Massachusetts Institute of Technology (MIT).

6) Digitizer

Digitizer

Digitizer is a computer input device that has a flat surface and usually comes with a stylus. It enables the user to draw images and graphics using the stylus as we draw on paper with a pencil. The images or graphics drawn on the digitizer appear on the computer monitor or display screen. The software converts the touch inputs into lines and can also convert handwritten text to typewritten words.

It can be used to capture handwritten signatures and data or images from taped papers. Furthermore, it is also used to receive information in the form of drawings and send output to a CAD (Computer-aided design) application and software like AutoCAD. Thus, it allows you to convert hand-drawn images into a format suitable for computer processing.

7) Microphone

Microphone

The microphone is a computer input device that is used to input the sound. It receives the sound vibrations and converts them into audio signals or sends to a recording medium. The audio signals are converted into digital data and stored in the computer. The microphone also enables the user to telecommunicate with others. It is also used to add sound to presentations and with webcams for video conferencing. A microphone can capture audio waves in different ways; accordingly the three most common types are described below:

i) Dynamic:

Microphone

It is the most commonly used microphone with a simple design. It has a magnet which is wrapped by a metal coil and a thin sheet on the front end of the magnet. The sheet transfers vibrations from sound waves to the coil and from coil to electric wires which transmit the sound like an electrical signal.

ii) Condenser:

Condenser Microphone

It is designed for audio recording and has a very sensitive and flat frequency response. It has a front plate called diaphragm and a back plate parallel to the front plate. When sound hits the diaphragm, it vibrates the diaphragm and alters the distance between the two plates. The changes in distance are transmitted as electric signals.

iii) Ribbon:

Ribbon Microphone

It is known for its reliability. It has a thin ribbon made of aluminum, duraluminum, or nanofilm suspended in a magnetic field. The sound waves cause vibrations in the ribbon, which generate a voltage proportional to the velocity of the vibration. The voltage is transmitted as an electrical signal. Early ribbon microphones had a transformer to increase the output voltage, but modern ribbon microphones come with advanced magnets to produce a strong signal.

8) Magnetic Ink Character Recognition (MICR)

MICR

MICR computer input device is designed to read the text printed with magnetic ink. MICR is a character recognition technology that makes use of special magnetized ink which is sensitive to magnetic fields. It is widely used in banks to process the cheques and other organizations where security is a major concern. It can process three hundred cheques in a minute with hundred-percent accuracy. The details on the bottom of the cheque (MICR No.) are written with magnetic ink. A laser printer with MICR toner can be used to print the magnetic ink.

The device reads the details and sends to a computer for processing. A document printed in magnetic ink is required to pass through a machine which magnetizes the ink, and the magnetic information is then translated into characters.

9) Optical Character Reader (OCR)

OCR

OCR computer input device is designed to convert the scanned images of handwritten, typed or printed text into digital text. It is widely used in offices and libraries to convert documents and books into electronic files.

It processes and copies the physical form of a document using a scanner. After copying the documents, the OCR software converts the documents into a two-color (black and white), version called bitmap. Then it is analyzed for light and dark areas, where the dark areas are selected as characters, and the light area is identified as background. It is widely used to convert hard copy legal or historic documents into PDFs. The converted documents can be edited if required like we edit documents created in ms word.

10) Digital camera:

Digital camera

It is a digital device as it captures images and records videos digitally and then stores them on a memory card. It is provided with an image sensor chip to capture images, as opposed to film used by traditional cameras. Besides this, a camera that is connected to your computer can also be called a digital camera.

It has photosensors to record light that enters the camera through the lens. When the light strikes the photosensors, each of the sensors returns the electrical current, which is used to create the images.

11) Paddle:

Paddle

It is a simple input device that is widely used in games. It is a wheel that is held by hand and looks like a volume knob on a stereo that is used to increase or decrease the volume. Paddle moves or controls cursor or any other objects in the game in a back-and-forth motion. It is widely used as an alternative to the joystick. Besides this, the term paddle also refers to many handheld devices designed to control a function in an electronic device, computer, etc.

12) Steering wheel:

Steering wheel

It is used as an input device in racing video games such as car racing games or in driving programs as virtual simulators to steer a vehicle. It works like the real steering wheel by allowing you to take a right or left turn. A steering wheel may be provided with acceleration and brake pedal devices and a mechanism for shifting gears. Thus, it makes racing games more adventurous and entertaining.

13) Gesture recognition devices:

Gesture recognition devices

These devices take human gestures as input. There are many such devices that respond to gestures. For example, Kinect is one such device that observes the movement of a player’s body and interprets these movements as inputs to video games. This feature is also available in certain tablets and smartphones where you can perform certain tasks such as taking pictures using finger gestures such as swiping, pinching, etc.

14) Light Gun:

Light Gun

As the name suggests, it is a pointing input device that is designed to point at and shoot the targets on the screen in a video game, or arcade, etc. The light gun was used for the first time on the MIT Whirwind computer. When the gun is pointed at the target on the screen and the trigger is pulled, the screen goes blank for a fraction of a second. During this moment, the photodiode, which is present in the barrel, determines where the gun is pointed. For example, shooting ducks in a duck hunt game.

15) Touchpad:

Touchpad

It is usually found in laptops as a substitute for the mouse. It allows you to move or control the cursor on the screen using your finger. Just like a mouse, it also has two buttons for right and left click. Using the touchpad, you can perform all the tasks that you do with a mouse, such as selecting an object on the screen, copy, paste, delete, open a file or folder, and more.

16) Remote:

Remote

It is a hardware device designed to control the functioning of a device, e.g., a TV remote that can be used to change channels, increase or decrease the volume, from a distance without leaving the seat. The first cordless TV remote was invented by Dr. Robert Adler of Zenith in 1956. The remote sends the electromagnetic waves to communicate with the device. These waves can be infrared rays, radio waves, etc.

17) Touch screen:

Touch screen

It is the display screen of a device such as a smartphone, tablet, etc., that allows users to interact or provide inputs to the device by using their finger. Today, most of the electronic devices come with touchscreen as an alternative to a mouse for navigating a graphical user interface. For example, by touching, you can unlock your phone, open emails, open files, play videos, etc. Besides this, it is used in lots of devices such as Camera, Car GPS, Fitness machine, etc.

The concept of the touch screen was first introduced and published by E.A. Johnson in 1965. The first touch screen was developed at the beginning of the 1970s by CERN engineers Frank Beck and Bent Stumpe.

18) VR:

VR

VR stands for virtual reality. It is an artificial or virtual environment which is generated by computers. A person can interact with virtual objects of this artificial environment using some input devices such as headsets, gloves, headphones, etc. For example, he or she can find himself or herself walking on a beach, watching a football match, walking in the sky, etc., without actually doing all this.

19) Webcam:

Webcam

Any camera which is connected to a computer is called a webcam. The in-built camera provided on a computer can also be considered a webcam. It is an input device as it can take pictures, and can be used to record videos if required. The pictures and videos are stored in the computer memory and can be displayed on the screen if required. Although it works almost the same as the digital camera, it is different from a digital camera, as it is designed to take compact digital photos that can be uploaded easily on the webpages and shared with others through the internet.

20) Biometric Devices:

Biometrics refers to a process in which a person is identified through his or her biological features such as fingerprints, eye cornea, face structure, etc. It is done by using biometric devices, which can be of different types based on their scanning features and abilities, such as:

i) Face Scanner:

Face Scanner

It is designed to identify a person by scanning his or her face. It takes the face measurements of a person. For example, the distance between eyes, nose, and mouth, etc., accordingly, it confirms the identity of a person. Besides this, it is smart enough to differentiate between a person’s picture and the real person.

ii) Hand Scanner:

Hand Scanner

The hand of a person can also be used to verify his or her identity as every person has a unique pattern of veins in the palm, just like fingerprints. This device takes advantage of this feature; it identifies a person by scanning the palm of his hand. It uses infrared light to scan veins’ patterns and blood flowing in them. Palm is even more unique than fingerprints.

iii) Fingerprint Scanner:

Fingerprint Scanner

It scans the fingerprints to identify people or for biometric authentication. This device is developed, keeping in mind the fact that no two persons in the world can have the same fingerprints. It is widely used in companies as a fingerprint attendance system to mark the attendance of employees. This type of scanners captures the pattern of valleys and ridges found on a finger and store it in the memory or database. When you press your finger on the given space, it verifies the identity by using its pattern-matching software.

iv) Retina or Iris Scanner:

Retina or Iris Scanner

It scans the retina or iris of a person’s eye to confirm the identity. This device is more secure than others as it is next to impossible to copy the retina or iris. It works by mapping the retina’s blood vessel patterns of the eye. The blood vessels of retina absorb light more easily as well as can be identified with appropriate lighting.

In this scan, a beam of low-energy infrared light falls on the retina through the scanner’s eyepiece. Then, the software captures the network of blood vessels in the retina and uses it to verify a person’s identity.

v) Voice Scanner:

Voice Scanner

It records the voice of a person and digitizes it to create a distinctive voice print or template. The voiceprints are stored in the database, and are used to verify the voice of a person to confirm his or her identity. The person is required to speak in the normal or same voice that was used to create a voice template. It is not much reliable as it can be misused using a tape recording.

Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 2: Computer Fundamentals Applications

by | Jan 6, 2022 | Computer Fundamentals

Business

A computer has high speed of calculation, diligence, accuracy, reliability, or versatility which has made it an integrated part in all business organizations.

Computer is used in business organizations for −

  • Payroll calculations
  • Budgeting
  • Sales analysis
  • Financial forecasting
  • Managing employee database
  • Maintenance of stocks, etc.

Banking

Today, banking is almost totally dependent on computers.

Banks provide the following facilities:

  • Online accounting facility, which includes checking current balance, making deposits and overdrafts, checking interest charges, shares, and trustee records.
  • ATM machines which are completely automated are making it even easier for customers to deal with banks.

Insurance

Insurance companies are keeping all records up-to-date with the help of computers. Insurance companies, finance houses, and stock broking firms are widely using computers for their concerns.

Insurance companies are maintaining a database of all clients with information showing −

  • Procedure to continue with policies
  • Starting date of the policies
  • Next due installment of a policy
  • Maturity date
  • Interests due
  • Survival benefits
  • Bonus

Education

The computer helps in providing a lot of facilities in the education system.

  • The computer provides a tool in the education system known as CBE (Computer Based Education).
  • CBE involves control, delivery, and evaluation of learning.
  • Computer education is rapidly increasing the graph of number of computer students.
  • There are a number of methods in which educational institutions can use a computer to educate the students.
  • It is used to prepare a database about performance of a student and analysis is carried out on this basis.

Marketing

In marketing, uses of the computer are following −

  • Advertising: With computers, advertising professionals create art and graphics, write and revise copy, and print and disseminate ads with the goal of selling more products.
  • Home Shopping : Home shopping has been made possible through the use of computerized catalogues that provide access to product information and permit direct entry of orders to be filled by the customers.

Healthcare

Computers have become an important part in hospitals, labs, and dispensaries. They are being used in hospitals to keep the record of patients and medicines. It is also used in scanning and diagnosing different diseases. ECG, EEG, ultrasounds and CT scans, etc. are also done by computerized machines.

Following are some major fields of health care in which computers are used.

  • Diagnostic System − Computers are used to collect data and identify the cause of illness.
  • Lab-diagnostic System − All tests can be done and the reports are prepared by computer.
  • Patient Monitoring System − These are used to check the patient’s signs for abnormality such as in Cardiac Arrest, ECG, etc.
  • Pharma Information System − Computer is used to check drug labels, expiry dates, harmful side effects, etc.
  • Surgery − Nowadays, computers are also used in performing surgery.

Engineering Design

Computers are widely used for Engineering purpose. One of the major areas is CAD (Computer Aided Design) that provides creation and modification of images. Some of the fields are:

  • Structural Engineering − Requires stress and strain analysis for design of ships, buildings, budgets, airplanes, etc.
  • Industrial Engineering − Computers deal with design, implementation, and improvement of integrated systems of people, materials, and equipment.
  • Architectural Engineering − Computers help in planning towns, designing buildings, determining a range of buildings on a site using both 2D and 3D drawings.

Military

Computers are largely used in defiance. Modern tanks, missiles, weapons, etc. Military also employs computerized control systems. Some military areas where a computer has been used are −

  • Missile Control
  • Military Communication
  • Military Operation and Planning
  • Smart Weapons

Communication

Communication is a way to convey a message, an idea, a picture, or speech that is received and understood clearly and correctly by the person for whom it is meant. Some main areas in this category are −

  • E-mail
  • Chatting
  • Usenet
  • FTP
  • Telnet
  • Video-conferencing

Government

Computers play an important role in government services. Some major fields in this category are −

  • Budgets
  • Sales tax department
  • Income tax department
  • Computation of male/female ratio
  • Computerization of voters lists
  • Computerization of PAN card
  • Weather forecasting

The basic parts without which a computer cannot work are as follows:

  • Processor: It executes instructions from software and hardware.
  • Memory: It is the primary memory for data transfer between the CPU and storage.
  • Motherboard: It is the part that connects all other parts or components of a computer.
  • Storage Device: It permanently stores the data, e.g., hard drive.
  • Input Device: It allows you to communicate with the computer or to input data, e.g., a keyboard.
  • Output Device: It enables you to see the output, e.g., monitor.

Computers are divided into different types based on different criteria. Based on the size, a computer can be divided into five types:

  1. Micro Computer
  2. Mini Computer
  3. Mainframe Computer
  4. Super Computer
  5. Workstations

1. Micro Computer:

It is a single-user computer which has less speed and storage capacity than the other types. It uses a microprocessor as a CPU. The first microcomputer was built with 8-bit microprocessor chips. The common examples of microcomputers include laptops, desktop computers, personal digital assistant (PDA), tablets, and smartphones. Microcomputers are generally designed and developed for general usage like browsing, searching for information, internet, MS Office, social media, etc.

2. Mini Computer:

Mini-computers are also known as “Midrange Computers.” They are not designed for a single. They are multi-user computers designed to support multiple users simultaneously. So, they are generally used by small businesses and firms. Individual departments of a company use these computers for specific purposes. For example, the admission department of a University can use a Mini-computer for monitoring the admission process.

3. Mainframe Computer:

It is also a multi-user computer capable of supporting thousands of users simultaneously. They are used by large firms and government organizations to run their business operations as they can store and process large amounts of data. For example, Banks, universities, and insurance companies use mainframe computers to store the data of their customers, students, and policyholders, respectively.

4. Super Computer:

Super-computers are the fastest and most expensive computers among all types of computers. They have huge storage capacities and computing speeds and thus can perform millions of instructions per second. The super-computers are task-specific and thus used for specialized applications such as large-scale numerical problems in scientific and engineering disciplines including applications in electronics, petroleum engineering, weather forecasting, medicine, space research and more. For example, NASA uses supercomputers for launching space satellites and monitoring and controlling them for space exploration.

5. Work stations:

It is a single-user computer. Although it is like a personal computer, it has a more powerful microprocessor and a higher-quality monitor than a microcomputer. In terms of storage capacity and speed, it comes between a personal computer and minicomputer. Work stations are generally used for specialized applications such as desktop publishing, software development, and engineering designs.

Benefits of Using a Computer:

  • Increases your productivity: A computer increases your productivity. For example, after having a basic understanding of a word processor, you can create, edit, store, and print the documents easily and quickly.
  • Connects to the Internet: It connects you to the internet that allows you to send emails, browse content, gain information, use social media platforms, and more. By connecting to the internet, you can also connect to your long-distance friends and family members.
  • Storage: A computer allows you to store a large amount of information, e.g., you can store your projects, eBooks, documents, movies, pictures, songs, and more.
  • Organized Data and Information: It not only allows you to store data but also enables you to organize your data. For example, you can create different folders to store different data and information and thus can search for information easily and quickly.
  • Improves your abilities: It helps write good English if you are not good at spelling and grammar. Similarly, if you are not good at math, and don’t have a great memory, you can use a computer to perform calculations and store the results.
  • Assist the physically challenged: It can be used to help the physically challenged, e.g., Stephen Hawking, who was not able to speak used computer to speak. It also can be used to help blind people by installing special software to read what is on the screen.
  • Keeps you entertained: You can use the computer to listen to songs, watch movies, play games and more.

The computer has become a part of our life. There are plenty of things that we do in a day are dependent on a computer. Some of the common examples are as follows:

  1. ATM: While withdrawing cash from an ATM, you are using a computer that enables the ATM to take instructions and dispense cash accordingly.
  2. Digital currency: A computer keeps a record of your transactions and balance in your account and the money deposited in your account in a bank is stored as a digital record or digital currency.
  3. Trading: Stock markets use computers for day to day trading. There are many advanced algorithms based on computers that handle trading without involving humans.
  4. Smartphone: The smartphone that we use throughout the day for calling, texting, browsing is itself a computer.
  5. VoIP: All voice over IP communication (VoIP) is handled and done by computers.
Part 12: Computer Fundamentals Keyboard Shortcut Keys

Part 1: Computer Fundamentals Basics

by | Jan 6, 2022 | Computer Fundamentals

Computer Fundamentals

Computer is an advanced electronic device that takes raw data as an input from the user and processes it under the control of a set of instructions (called program), produces a result (output), and saves it for future use. This tutorial explains the foundational concepts of computer hardware, software, operating systems, peripherals, etc. along with how to get the most value and impact from computer technology.

Functionalities of a Computer

If we look at it in a very broad sense, any digital computer carries out the following five functions −

Step 1 − Takes data as input.

Step 2 − Stores the data/instructions in its memory and uses them as required.

Step 3 − Processes the data and converts it into useful information.

Step 4 − Generates the output.

Step 5 − Controls all the above four steps.

Advantages of Computers

Following are certain advantages of computers.

High Speed

  • Computer is a very fast device.
  • It is capable of performing calculation of very large amount of data.
  • The computer has units of speed in microsecond, nanosecond, and even the picosecond.
  • It can perform millions of calculations in a few seconds as compared to man who will spend many months to perform the same task.

Accuracy

  • In addition to being very fast, computers are very accurate.
  • The calculations are 100% error free.
  • Computers perform all jobs with 100% accuracy provided that the input is correct.

Storage Capability

  • Memory is a very important characteristic of computers.
  • A computer has much more storage capacity than human beings.
  • It can store large amount of data.
  • It can store any type of data such as images, videos, text, audio, etc.

Diligence

  • Unlike human beings, a computer is free from monotony, tiredness, and lack of concentration.
  • It can work continuously without any error and boredom.
  • It can perform repeated tasks with the same speed and accuracy.

Versatility

  • A computer is a very versatile machine.
  • A computer is very flexible in performing the jobs to be done.
  • This machine can be used to solve the problems related to various fields.
  • At one instance, it may be solving a complex scientific problem and the very next moment it may be playing a card game.

Reliability

  • A computer is a reliable machine.
  • Modern electronic components have long lives.
  • Computers are designed to make maintenance easy.

Automation

  • Computer is an automatic machine.
  • Automation is the ability to perform a given task automatically. Once the computer receives a program i.e., the program is stored in the computer memory, then the program and instruction can control the program execution without human interaction.

Reduction in Paper Work and Cost

  • The use of computers for data processing in an organization leads to reduction in paper work and results in speeding up the process.
  • As data in electronic files can be retrieved as and when required, the problem of maintenance of large number of paper files gets reduced.
  • Though the initial investment for installing a computer is high, it substantially reduces the cost of each of its transaction.

Disadvantages of Computers

Following are certain disadvantages of computers.

No I.Q.

  • A computer is a machine that has no intelligence to perform any task.
  • Each instruction has to be given to the computer.
  • A computer cannot take any decision on its own.

Dependency

  • It functions as per the user’s instruction, thus it is fully dependent on humans.

Environment

  • The operating environment of the computer should be dust free and suitable.

No Feeling

  • Computers have no feelings or emotions.
  • It cannot make judgment based on feeling, taste, experience, and knowledge unlike humans.

 

History of Computers

The first counting device was used by the primitive people. They used sticks, stones and bones as counting tools. As human mind and technology improved with time more computing devices were developed. Some of the popular computing devices starting with the first to recent ones are described below;

Abacus

The history of computer begins with the birth of abacus which is believed to be the first computer. It is said that Chinese invented Abacus around 4,000 years ago.

It was a wooden rack which has metal rods with beads mounted on them. The beads were moved by the abacus operator according to some rules to perform arithmetic calculations. Abacus is still used in some countries like China, Russia and Japan. An image of this tool is shown below;

Computer Abacus 1

Napier’s Bones

It was a manually-operated calculating device which was invented by John Napier (1550-1617) of Merchiston. In this calculating tool, he used 9 different ivory strips or bones marked with numbers to multiply and divide. So, the tool became known as “Napier’s Bones. It was also the first machine to use the decimal point.

Computer napier bones 1

Pascaline

Pascaline is also known as Arithmetic Machine or Adding Machine. It was invented between 1642 and 1644 by a French mathematician-philosopher Biaise Pascal. It is believed that it was the first mechanical and automatic calculator.

Pascal invented this machine to help his father, a tax accountant. It could only perform addition and subtraction. It was a wooden box with a series of gears and wheels. When a wheel is rotated one revolution, it rotates the neighboring wheel. A series of windows is given on the top of the wheels to read the totals. An image of this tool is shown below;

Computer pascaline 1

Stepped Reckoner or Leibnitz wheel

It was developed by a German mathematician-philosopher Gottfried Wilhelm Leibnitz in 1673. He improved Pascal’s invention to develop this machine. It was a digital mechanical calculator which was called the stepped reckoner as instead of gears it was made of fluted drums. See the following image;

Computer Stepped reckoner or leibnitz wheel 1

Difference Engine

In the early 1820s, it was designed by Charles Babbage who is known as “Father of Modern Computer”. It was a mechanical computer which could perform simple calculations. It was a steam driven calculating machine designed to solve tables of numbers like logarithm tables.

Computer Difference engine 1

Analytical Engine

This calculating machine was also developed by Charles Babbage in 1830. It was a mechanical computer that used punch-cards as input. It was capable of solving any mathematical problem and storing information as a permanent memory.

Computer Analytical engine 1

Tabulating Machine

It was invented in 1890, by Herman Hollerith, an American statistician. It was a mechanical tabulator based on punch cards. It could tabulate statistics and record or sort data or information. This machine was used in the 1890 U.S. Census. Hollerith also started the Hollerith?s Tabulating Machine Company which later became International Business Machine (IBM) in 1924.

Computer Tabulating machine 1

Differential Analyzer

It was the first electronic computer introduced in the United States in 1930. It was an analog device invented by Vannevar Bush. This machine has vacuum tubes to switch electrical signals to perform calculations. It could do 25 calculations in few minutes.

Computer Differential analyzer 1

Mark I

The next major changes in the history of computer began in 1937 when Howard Aiken planned to develop a machine that could perform calculations involving large numbers. In 1944, Mark I computer was built as a partnership between IBM and Harvard. It was the first programmable digital computer.

Computer mark 1

Generations of Computers

A generation of computers refers to the specific improvements in computer technology with time. In 1946, electronic pathways called circuits were developed to perform the counting. It replaced the gears and other mechanical parts used for counting in previous computing machines.

In each new generation, the circuits became smaller and more advanced than the previous generation circuits. The miniaturization helped increase the speed, memory and power of computers. There are five generations of computers which are described below;

First Generation Computers

The first generation (1946-1959) computers were slow, huge and expensive. In these computers, vacuum tubes were used as the basic components of CPU and memory. These computers were mainly depended on batch operating system and punch cards. Magnetic tape and paper tape were used as output and input devices in this generation;

Some of the popular first generation computers are;

  • ENIAC ( Electronic Numerical Integrator and Computer)
  • EDVAC ( Electronic Discrete Variable Automatic Computer)
  • UNIVACI( Universal Automatic Computer)
  • IBM-701
  • IBM-650

Second Generation Computers

The second generation (1959-1965) was the era of the transistor computers. These computers used transistors which were cheap, compact and consuming less power; it made transistor computers faster than the first generation computers.

In this generation, magnetic cores were used as the primary memory and magnetic disc and tapes were used as the secondary storage. Assembly language and programming languages like COBOL and FORTRAN, and Batch processing and multiprogramming operating systems were used in these computers.

Some of the popular second generation computers are;

  • IBM 1620
  • IBM 7094
  • CDC 1604
  • CDC 3600
  • UNIVAC 1108

Third Generation Computers

The third generation computers used integrated circuits (ICs) instead of transistors. A single IC can pack huge number of transistors which increased the power of a computer and reduced the cost. The computers also became more reliable, efficient and smaller in size. These generation computers used remote processing, time-sharing, multi programming as operating system. Also, the high-level programming languages like FORTRON-II TO IV, COBOL, PASCAL PL/1, ALGOL-68 were used in this generation.

Some of the popular third generation computers are;

  • IBM-360 series
  • Honeywell-6000 series
  • PDP(Personal Data Processor)
  • IBM-370/168
  • TDC-316

Fourth Generation Computers

The fourth generation (1971-1980) computers used very large scale integrated (VLSI) circuits; a chip containing millions of transistors and other circuit elements. These chips made this generation computers more compact, powerful, fast and affordable. These generation computers used real time, time sharing and distributed operating system. The programming languages like C, C++, DBASE were also used in this generation.

Some of the popular fourth generation computers are;

  • DEC 10
  • STAR 1000
  • PDP 11
  • CRAY-1(Super Computer)
  • CRAY-X-MP(Super Computer)

Fifth Generation Computers

In fifth generation (1980-till date) computers, the VLSI technology was replaced with ULSI (Ultra Large Scale Integration). It made possible the production of microprocessor chips with ten million electronic components. This generation computers used parallel processing hardware and AI (Artificial Intelligence) software. The programming languages used in this generation were C, C++, Java, .Net, etc.

Some of the popular fifth generation computers are;

  • Desktop
  • Laptop
  • NoteBook
  • UltraBook
  • ChromeBook
Part 12: Internet of Things(IOT) Sustainability and Challenges

Part 12: Internet of Things(IOT) Sustainability and Challenges

by | Jan 6, 2022 | Internet of Things (IOT)

Understand how IoT can address sustainability and  challenges

As our world becomes more and more connected, we use smart devices to overcome different obstacles in our day-to-day lives. But what happens when we turn IoT technology toward global-scale problems like sustainability?

On this two-week course, you’ll explore the fundamentals of the Internet of Things (IoT), and how we can use this technology to overcome different sustainability challenges that we face today.

Guided by the experts at The Mind Lab and Tech Futures Lab, you’ll delve into case studies to discover how IoT applications can lead to sustainable decision-making. Using examples from smart cities, transport, utilities, and more, you’ll identify the positive and negative implications of technology use in working towards a brighter future.

Delve into the fundamentals of IoT including data management

You’ll be introduced to the technological and business fundamentals of IoT including frameworks of strategy, business value, competitive environment, and user value proposition.

To help you understand how IoT can be utilised in your own contexts, you’ll apply your knowledge through a range of learning activities in a connected environments framework.

Discover how IoT is interfacing with other technologies including AI

Finally, you’ll explore how IoT is also teaming up with other technologies to further help address sustainability challenges.

You’ll explore artificial intelligence, machine learning, 5G, and more as well as examining a range of case studies in key industry contexts to see IoT solutions in action.

With this knowledge, you’ll be able to evaluate the role of IoT in working toward a sustainable future.

 

Topics of IOT:

  1. Introduction to the technical dimensions of the Internet of Things (IoT) including hardware and software essentials and the role of technology platforms
  2. Introduction to the business dimensions of the Internet of Things (IoT) and the importance of market analysis, business strategy, value proposition, and data governance in planning, deploying, and operating IoT systems.
  3. Overview of the benefits of the Internet of Things (IoT) for tracking, measuring, and sensing to collect data that can inform decision-making toward more sustainable futures with reference to the New Zealand and International context.
  4. Evaluation and reflection of the role of IoT in addressing sustainability challenges in a range of case studies in key industry contexts.
Part 12: Internet of Things(IOT) Sustainability and Challenges

Part 11: Internet of Things(IOT) Liability

by | Jan 5, 2022 | Internet of Things (IOT)

Internet of Things Liability

The security flaws of IoT and its ability to perform certain tasks open the door to any associated liability. The three main areas of concern are device malfunction, attacks, and data theft. These issues can result in a wide variety of damages.

Device Malfunction

IoT introduces a deeper level of automation which can have control over critical systems, and systems impacting life and property. When these systems fail or malfunction, they can cause substantial damage; for example, if an IoT furnace control system experiences a glitch, it may fail in an unoccupied home and cause frozen pipes and water damage. This forces organizations to create measures against it.

This smart thermostat allows attackers to gain remote access, and breach the rest of the network.

Cyber Attacks

IoT devices expose an entire network and anything directly impacted to the risk of attacks. Though those connections deliver powerful integration and productivity, they also create the perfect opportunity for mayhem like a hacked stove or fire safety sprinkler system. The best measures against this address the most vulnerable points, and provide custom protections such as monitoring and access privileges.

Some of the most effective measures against attacks prove simple −

  • Built-in Security − Individuals and organizations should seek hardened devices, meaning those with security integrated in the hardware and firmware.
  • Encryption − This must be implemented by the manufacturer and through user systems.
  • Risk Analysis − Organizations and individuals must analyze possible threats in designing their systems or choosing them.
  • Authorization − Devices, whenever possible, must be subject to privilege policies and access methods.

Bitdefender BOX secures all connected devices in the home.

Data Theft

Data, IoT’s strength and weakness, proves irresistible to many. These individuals have a number of reasons for their interest − the value of personal data to marketing/advertising, identity theft, framing individuals for crimes, stalking, and a bizarre sense of satisfaction. Measures used to fight attacks are also effective in managing this threat.

The three main liability areas that can arise relating to IoT are:

  • IoT device malfunction, failure, and/or inaccuracy
  • Cyber-attacks and the theft of personal and/or corporate data stored on the device
  • Use of IoT devices and/or software that cause physical or financial harm such as botnets

When Intelligent Devices go wrong

As an example of a liability is covered in the article in the Washington Post “Self-driving Uber vehicle strikes and kills pedestrian” stimulated my thinking about liabilities with IoT devices, platforms, and services. The article stated “Uber abruptly halted testing of its autonomous vehicles across North America on Monday, after a 49-year old woman was struck and killed by one of its cars while crossing a Tempe, Ariz. street Sunday night.” Who is liable? Is this a criminal or civil case? Is it covered by state or federal law? Was the driverless car insured?

The Blame Game has begun

It will be difficult for those blaming the driverless car and those who want to exonerate it. The Wired article “Uber Autonomous SUV ‘Not Necessarily’ At Fault In Woman’s Death”

suggests that the death was the responsibility of the person who was hit by the car. This may turn out to be true. But there will be cases where the injured pedestrian was not a fault. What then?

What is Product Liability?

There is a definition of product liability posted by FindLaw: “Product liability refers to a manufacturer or seller being held liable for placing a defective product into the hands of the consumer. Responsibility for a product defect that causes injury lies with all sellers of the product who are in the distribution chain. In general terms, the law requires that a product meet the ordinary expectations of the consumer. When a product has an unexpected defect or damage, the product cannot be said to meet the ordinary expectations of the consumer”

Is the IoT Endpoint Accurate?

IoT endpoints may not be accurate enough to make decisions using the IoT data. What if business decisions are made assuming their accuracy? The analytics will look good, but the raw data can be in error or devices can be hacked. I cannot confront the IoT endpoint itself, so who has the liability for errors: the endpoint manufacturer, endpoint implementer, the data analytics system, consultants, MSP, or the internal IT staff?

If the data is not accurate, and the organization makes decisions on faulty data, then who is responsible? Could the faulty decision lead to financial or reputation loss? What if someone was harmed because of the faulty data?

Who Does this Impact?

The chain of distribution for a product covers many organizations not just the entity that owns or rents the IoT devices including:

  • Product manufacturer
  • Manufacturer of component parts
  • The product assembly party
  • Product installer
  • The wholesaler and the retail outlet that sold the product

IoT devices and the platforms supporting the IoT devices add elements that can change the product which include:

  • The software that runs the product, whether it is provided by the manufacturer or uses third-party software
  • Networks that provide connections to the product
  • Its information security and access
  • The organization that employs the IoT devices

The degree of liability may be hard to assign, so everyone may be sued and the courts will work out the degrees of liability.

IoT Liabilities issues are a Work in Progress

Those organizations that choose to implement IoT devices need to thoroughly analyze the agreements they have with their suppliers of products and services to ensure that they are not the only ones liable for IoT problems. It may be that in some cases the potential agreements with suppliers are biased to the point where the organization should not buy the products or subscribe to the service.

Part 12: Internet of Things(IOT) Sustainability and Challenges

Part 10: Internet of Things Security and Identity Protection

by | Jan 5, 2022 | Internet of Things (IOT)

Every connected device creates opportunities for attackers. These vulnerabilities are broad, even for a single small device. The risks posed include data transfer, device access, malfunctioning devices, and always-on/always-connected devices.

The main challenges in security remain the security limitations associated with producing lowcost devices, and the growing number of devices which creates more opportunities for attacks.

Security Spectrum

The definition of a secured device spans from the most simple measures to sophisticated designs. Security should be thought of as a spectrum of vulnerability which changes over time as threats evolve.

Security must be assessed based on user needs and implementation. Users must recognize the impact of security measures because poorly designed security creates more problems than it solves.

Example − A German report revealed hackers compromised the security system of a steel mill. They disrupted the control systems, which prevented a blast furnace from being shut down properly, resulting in massive damage. Therefore, users must understand the impact of an attack before deciding on appropriate protection.

Challenges

Beyond costs and the ubiquity of devices, other security issues plague IoT −

  • Unpredictable Behavior − The sheer volume of deployed devices and their long list of enabling technologies means their behavior in the field can be unpredictable. A specific system may be well designed and within administration control, but there are no guarantees about how it will interact with others.
  • Device Similarity − IoT devices are fairly uniform. They utilize the same connection technology and components. If one system or device suffers from a vulnerability, many more have the same issue.
  • Problematic Deployment − One of the main goals of IoT remains to place advanced networks and analytics where they previously could not go. Unfortunately, this creates the problem of physically securing the devices in these strange or easily accessed places.
  • Long Device Life and Expired Support − One of the benefits of IoT devices is longevity, however, that long life also means they may outlive their device support. Compare this to traditional systems which typically have support and upgrades long after many have stopped using them. Orphaned devices and abandonware lack the same security hardening of other systems due to the evolution of technology over time.
  • No Upgrade Support − Many IoT devices, like many mobile and small devices, are not designed to allow upgrades or any modifications. Others offer inconvenient upgrades, which many owners ignore, or fail to notice.
  • Poor or No Transparency − Many IoT devices fail to provide transparency with regard to their functionality. Users cannot observe or access their processes, and are left to assume how devices behave. They have no control over unwanted functions or data collection; furthermore, when a manufacturer updates the device, it may bring more unwanted functions.
  • No Alerts − Another goal of IoT remains to provide its incredible functionality without being obtrusive. This introduces the problem of user awareness. Users do not monitor the devices or know when something goes wrong. Security breaches can persist over long periods without detection.

IOT Identity Protection

IoT devices collect data about their environment, which includes people. These benefits introduce heavy risk. The data itself does not present the danger, however, its depth does. The highly detailed data collection paints a very clear picture of an individual, giving criminals all the information they need to take advantage of someone.

People may also not be aware of the level of privacy; for example, entertainment devices may gather A/V data, or “watch” a consumer, and share intimate information. The demand and price for this data exacerbates the issue considering the number and diversity of parties interested in sensitive data.

Problems specific to IoT technology lead to many of its privacy issues, which primarily stem from the user’s inability to establish and control privacy −

Consent

The traditional model for “notice and consent” within connected systems generally enforces existing privacy protections. It allows users to interact with privacy mechanisms, and set preferences typically through accepting an agreement or limiting actions. Many IoT devices have no such accommodations. Users not only have no control, but they are also not afforded any transparency regarding device activities.

The Right to be Left Alone

Users have normal expectations for privacy in certain situations. This comes from the commonly accepted idea of public and private spaces; for example, individuals are not surprised by surveillance cameras in commercial spaces, however, they do not expect them in their personal vehicle. IoT devices challenge these norms people recognize as the “right to be left alone.” Even in public spaces, IoT creeps beyond the limits of expected privacy due to its power.

Indistinguishable Data

IoT deploys in a wide variety of ways. Much of IoT implementation remains group targeted rather than personal. Even if users give IoT devices consent for each action, not every system can reasonably process every set of preferences; for example, small devices in a complex assembly cannot honor the requests of tens of thousands of users they encounter for mere seconds.

Granularity

Modern big data poses a substantial threat to privacy, but IoT compounds the issue with its scale and intimacy. It goes not only where passive systems cannot, but it collects data everywhere. This supports creation of highly detailed profiles which facilitate discrimination and expose individuals to physical, financial, and reputation harm.

Comfort

The growth of IoT normalizes it. Users become comfortable with what they perceive as safe technology. IoT also lacks the transparency that warns users in traditional connected systems; consequently, many act without any consideration for the potential consequences.

Part 12: Internet of Things(IOT) Sustainability and Challenges

Part 9: IOT Eclipse and Contiki

by | Jan 5, 2022 | Internet of Things (IOT)

Eclipse IoT is an ecosystem of entities (industry and academia) working together to create a foundation for IoT based exclusively on open source technologies. Their focus remains in the areas of producing open source implementations of IoT standard technology; creating open source frameworks and services for utilization in IoT solutions; and developing tools for IoT developers.

Smarthome Project

SmartHome is one of Eclipse IoT’s major services. It aims to create a framework for building smart home solutions, and its focus remains heterogeneous environments, meaning assorted protocols and standards integration.

SmartHome provides uniform device and information access to facilitate interaction between devices. It consists of OSGi bundles capable of deployment in an OSGi runtime, with OSGi services defined as extension points.

OSGi bundles are Java class groups and other resources, which also include detailed manifest files. The manifest contains information on file contents, services needed to enhance class behavior, and the nature of the aggregate as a component. Review an example of a manifest below −

Bundle-Name : Hi Everyone                        // Bundle Name 
Bundle-SymbolicName : xyz.xyz.hievery1           // Header specifying an identifier 
Bundle-Description : A Hi Everyone bundle        // Functionality description 
Bundle-ManifestVersion : 2                       // OSGi specification 
Bundle-Version : 1.0.0                           // Version number of bundle 
Bundle-Activator : xyz.xyz.Activator             // Class invoked on bundle activation 
Export-Package : xyz.xyz.helloworld;version = "1.0.0" // Java packages available externally 
Import-Package : org.osgi.framework;version = "1.3.0"   // Java packages needed from 
// external source

Eclipse SCADA

Eclipse SCADA, another major Eclipse IoT service, delivers a means of connecting various industrial instruments to a shared communication system. It also post-processes data and sends data visualizations to operators. It uses a SCADA system with a communication service, monitoring system, archive, and data visualization.

Eclipse SCADA

It aims to be a complete, state-of-the-art open source SCADA system for developing custom solutions. Its supported technologies and tools include shell applications, JDBC, Modbus TCP and RTU, Simatic S7 PLC, OPC, and SNMP.

Contiki

Contiki is an operating system for IoT that specifically targets small IoT devices with limited memory, power, bandwidth, and processing power. It uses a minimalist design while still packing the common tools of modern operating systems. It provides functionality for management of programs, processes, resources, memory, and communication.

It owes its popularity to being very lightweight (by modern standards), mature, and flexible. Many academics, organization researchers, and professionals consider it a go-to OS. Contiki only requires a few kilobytes to run, and within a space of under 30KB, it fits its entire operating system − a web browser, web server, calculator, shell, telnet client and daemon, email client, vnc viewer, and ftp. It borrows from operating systems and development strategies from decades ago, which easily exploited equally small space.

Contiki Communication

Contiki supports standard protocols and recent enabling protocols for IoT −

  • uIP (for IPv4) − This TCP/IP implementation supports 8-bit and 16-bit microcontrollers.
  • uIPv6 (for IPv6) − This is a fully compliant IPv6 extension to uIP.
  • Rime − This alternative stack provides a solution when IPv4 or IPv6 prove prohibitive. It offers a set of primitives for low-power systems.
  • 6LoWPAN − This stands for IPv6 over low-power wireless personal area networks. It provides compression technology to support the low data rate wireless needed by devices with limited resources.
  • RPL − This distance vector IPv6 protocol for LLNs (low-power and lossy networks) allows the best possible path to be found in a complex network of devices with varied capability.
  • CoAP − This protocol supports communication for simple devices, typically devices requiring heavy remote supervision.

Dynamic Module Loading

Dynamic module loading and linking at run-time supports environments in which application behavior changes after deployment. Contiki’s module loader loads, relocates, and links ELF files.

The Cooja Network Simulator

Cooja, the Contiki network simulator, spawns an actual compiled and working Contiki system controlled by Cooja.

Using Cooja proves simple. Simply create a new mote type by selecting the Motes menu and Add Motes → Create New Mote Type. In the dialog that appears, you choose a name for the mote, select its firmware, and test its compilation.

Motes Menu

After creation, add motes by clicking Create. A new mote type will appear to which you can attach nodes. The final step requires saving your simulation file for future use.