INFORMATION TECHNOLOGY

INFORMATION TECHNOLOGY

Definition: Information Technology mainly refers to gathering, storages, processing, retrieving           and distributing.

Information: Processed data is called information.

Technology: Technology is a science which we can apply in any application.

Data: Raw of facts

Datum: Singular term of data is called datum.

Characteristics of computer: Now a days computer is playing a main role in every field of life and has become the need of people just like television, telephone (or) other electronic devices at home. The important characteristics of computer are given below

It solves the human problems very quickly as well as accurately.

            1. Speed
            2. Accuracy
            3. Reliability
            4. Storage
            5. Auto Machine
            6. Versatility
            7. Communications
            8. Diligence
            9. Precision
            10. No feelings

      Limitations of computer:

1. It cannot think
2. It cannot learn by their experience

Speed: Computer is a very high speed electronic device. The operations on the data inside the computer (or) affirmed through electronic circuits according to the given instructions.Computer can perform millions of operations on the data in one second. The use of computer is usually measured in Mega Hertz (MHz), Gega Hertz (GHz).

Accuracy: Computer is a very accurate device. It gives accurate output providing the correct input; it means the output is totally depends on the input data. If the input data is incorrect and the output will be incorrect. It is known as Garbage Input and Garbage Output.

Reliability: In modern days computer have very failure rate in general computers are very reliable.

Storage: Computer has internal as well as external storage and also known as primary and secondary. In secondary storage large amount of data can be stored for further use.

Auto Machine: It performs automatically without interfering the user during the operations. It control automatically different devices attached with the computer.

Versatility: Versatility means flexible Modern computer can perform different kinds of tasks one by one(or) simultaneously.

Communication: Today computer is mostly used to exchange information.
Ex: Email or chatting. 

Diligence: A Computer can continuously work for hours without creating any error. It does not get tired while working after hours.

No feelings: It has no feelings. Computer cannot make such judgments at its own. Their judgments are totally based on instructions given by the user.

Consistency: Computer can repeat actions consistently ( again and again) without losing its concentration. A computer will carry out the activity with same way every time.

Precision: Computers are not only fast and consistence but also perform operations accurately and precisely.

Limitations of computer:

1. Without a programmer computer is nothing
2. Although it is faster, diligent, accurate and versatility than human being, it cannot replace
3. Computer does not have any intelligence. It cannot carry any task at its own.
4. They do not have emotions as human being.
5. They cannot think(or) they cannot take any decisions.
6. They cannot learn by their experience.

Classifications of Computers:

On the basis of working principles, they can be categorise into analog, digital and hybrid.

Analog computer: It is a form of a computer that uses continuous physical phenomenon  such as electrical, mechanical and hydraulic quantities to model the problem being solved (or) inputs are given inform of volts, pressure and temperature to this type of analog computers.

Ex: Speedometer, industries, plants etc.

Digital computer: A computer that perform calculations a logical operations with quantities represented as digits. Usually in the Binary number system. In the Binary system 0 and 1 are easily expressed in the computer circuit by the presence (1) or obsence (0), light(1), dark(0), on (1) and off (0)

A series of 8 consecutive bits is called byte.

The 8 bits ( 1byte) permits 256 different on, off combinations.

Ex: Reservation system, scientific investigation, data processing, word processing, applications, electronic games etc,

Hybrid computer: It is a combination of analog and digital. A hybrid computer system set up cost effective method of performing complex stimulations. Hybrid computer is a digital computer that aspects analog signals and converts them into digital and process them into digital form.

They hybrid computer capable of real time solutions has been less expensive than any equivalent digital computer.

Ex: Computerize Tomography, Scientific applications (or) controlling industrial process.

Types of computer: Computers are categorized into different types depending on the size of the computer.

Super computer

1.            Mani Frame
2.            Mini Computer
3.            Micro Computer
4.            Work Stations
5.            Server

Super Computers: Super computer was introduced in 1960’s very expensive, fastest machine typically  used in specialized areas, they have high processing speed compare to other computers, they have also multi processing speed and multi processing technique. Super computers are mainly being used for defence, whether forecasting, biomedical research, remote sensing, air craft design and other areas of science and Technology.

Examples of super computers are CRAY YMP, CRAY2, param from India.

The speed of super computer is measured in teraflops ( Tera Flops)

Main Frames are powerful computers used mainly by large organizations for critical operations, typically bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial processing.

Mini Computer:  It is a multi user computers that lies in between middle range of the computing spectrum. In between the largest multi user system and smallest single user system. the minicomputer supports programming language that includes basic, Pascal, Cobol, C and Fortran.

Work Station: Work station is a high and micro computer designed for technical (or) scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi user operating system. They are optimized for visualization and manipulation of different types of complex data such as 3D mechanical design, engineering simulation, animation and rendering of images and mathematical plots.

Servers: A server computer is a computer is a computer that link other computers are electronic devices together. They often provide essential services across a network either to private users inside a large organization or to public users via an Internet. Many servers have dedicated functionality such as web-servers, print –servers and data base servers. It provides services to other computing system called client over a network. A typical server is a computing systems called client over a network. A typical server is a computing system that operates continuously on a network and waits for request to respond.

Micro computer: Micro Computers were first available for wide spread use in 1970’s.A micro processor is a product of the micro mini authorization of electronic circuite called chip. A size of chips which are about 30, 000 of an inch thick, varying area from figure nail’s size to postage stamp size.

Input: Data and instructions enter input units in forms that depends upon particulars device i.e. use

For example, data is entered from a key board in a manner similar to typing. All inputs most provide a computer with data that is transformed into binary codes. That primary memory of computer is designed to accept. This transformation is accomplished by units called input “interface”

Output unit: As computers work with Binary code, the results produced are also in Binary form. Hence before supplying the results to the outside world it must be converted to human acceptable form this task is accomplished by units called output ‘interface”.

Arithmetic Logical Unit(ALU): The arithmetic logical unit(ALU) of a computer system is the place where the actual execution of the instructions takes place during the processing operation. To be more precise all calculations are performed and all comparisons are made in the ALU. The data may thus who form primary storage to ALU and back way to more many times before the processing is over ALU’s are designed to perform the four basic arithmetic operations ADD, SUBTRACT, MULTIPLY, DIVIDE and logic operations or comparisons such as less than, greater than, equal to etc.

Control Unit: By selecting, Interpreting and seeing to the execute of the programming the control units is able to maintenance order and direct to operations of the entire system or Control unit acts as a central nervous system.

Central Processing Unit: The control unit and ALU of a computer system are jointly known as Central processing unit(CPI) the CPU is  the brain of any computer system.

Generations of Computer:

First Generation: The first generation computers were made up of vacuum tubles, each computer has had many as thousands of vacuum tube and hence the first generation computers were extremely large in size and required more space. These computers generated considerable amount of heat and had poor reliability.

The characteristics of first generation:

1.       Vacuum tubes were used in electronic circuits
2.       Magnetic drums were used has internal storage
3.       These computers used only machine language
4.       Mainly used in scientific applications
5.       Processing speed was very slow

Advantage:

1. Vacuum tube technology made possible and advert of electronic digital computers.
2. These computers were the fastest calculating devices of their time

Disadvantages:

1. Too large in size
2. Un reliable
3. Large amount of heat and burnt out frequently
4. Frequent hard ware failures
5. Air-conditioner was required

Second Generation:  In second generation, computers were made up of transistors. Transistors were more reliable, small in size and required low power. In second generation computers in addition to the main memory and external memory like magnetic tapes, magnetic discs were used. The second generation computers led to the development of high level languages like FORTRAN.

The characteristics of Second generation computer:

1. Magnetic cores has primary storage media
2. Input, output operations made faster
3. Increase in magnetic storage capacity use of high level programming languages ( FORTRAN, ALGO, COBAL,APL)

Advantages:

1. Small in size
2. Move reliable
3. Fast execution
4. Less power consuming
5. Less prone to hard ware failures.

Disadvantages:

1. Air condition required
2. Frequent- maintenance required
3. Costly

Third Generation: Integrated circuits were introduced. Hundreds of transistors were incorporated on a single silicon chip and hence with IC’s computers would be made smaller, more reliable and less expensive. Magnetic disks were used for Secondary storage.

Characteristics of Third generation:

1. High storage capacity
2. Simple input –output operations
3. Low heat generated
4. High speed
5. Easily portable
6. Maintenance cost is low
7. Easier and cheaper.

Disadvantage: Highly sophisticated technology required for the manufacturing of IC chip.

Fourth Generation: In this we use large scale integrated  circuit ( LSIC) which has led to the development of very small but extremely powerful computer. The whole computer circuits were soon available on a single chip, the size of a postage stamp.

The characteristics of fourth generation computers:

1. Use large scale integrated circuits
2. Increase storage capacity and high speed
3. Mini computers, micro processors and micro computers are extremely used. This can be used for different applications.

Advantages:

1. Smallest in size because of high component density
2. Very reliable
3. Much faster in computation
4. Easily portable
5. Cheapest among all generations

Disadvantages:

Highly sophisticated technology required for the manufacture of LSI chips.

Fifth generation:

The main aim to bring machines the genuine I.Q. The ability to reason logically and with real knowledge of words. These computers are yet come.

Memory:     Any storage unit of a computer system is ranked according to the following criteria.

Access time: This is a time required to locate and retrieve stored data from storage unit in response to a programme instruction. The fast access time is referred.

Storage capacity: It is the amount of data that can be stored in the storage unit a large capacity is desired.

Cost per bit of storage: Goal is to minimum  cost.

Main memory or primary memory: A primary memory can be used

1. To store the input data for processing it later.
2. To store the data which is under process.
3. To store the final result after the processing is over.
4. To store the programme which  is in current use.

There are two types of main memory

1.      Read Only Memory (ROM)
2.      Radom Access Memory (RAM)

Read only memory (ROM): The ROM is one in which information is permanently stored (or) read only memory is a non volatile memory. The information from the memory can only be read and it is not possible to write fresh information into it. This is the reason why we called read only memory. When the power supply is switched off, the information stored inside a ROM is not lost.

There are 2 types of ROM’s i.e EPROM( Erasable programmable read only Memory) & EEPROM (Electrically erasable programmable read only memory).

Random Access memory ( RAM): Primary storage is usually referred to as Random Access Memory because it is possible to Randomly select and use any location of this memory to directly store, retrieve data and instructions. Ram is easy to access as any other location and takes the same amount of time it is a volatile memory.

Cache Memory: A special very high speed memory is sometimes used to increase the speed of processing by making current programmes and data available to the CPU at the rapid rate. CPU speed is quite high compare to the access time of main memory. Cache memory is used to compensate the speed between CPU and RAM. Cache is stored segments of programmes currently being executed or- temporary data of frequently needed in the present calculation. Cache memory is not addressed by the user to the computer system.

Secondary storage Devise: It is desirable that operating speed of the primary storage of computers be as fast as possible because most of the transfer of data to and from the processing unit is via the main memory. For these reason storage devices are have very fast access  time as such as semi- conductors are generally chosen for the design of the main memory. Unfortunately the storage capacity of a main memory is limited. It is not sufficient to store large volume of data in today’s computer world. As a result additional memory called the auxiliary memory(or) secondary storage is used in most computer systems. The operating speeds of secondary storage system for slower than that of primary storage. this memory is referred as Back up storage because it is used to store large volume of data on a permanent basis.

Magnetic Disk: A magnetic disk is a thin circular metal plate coated with magnetic material on both sides, it is similar like Gram-phone record. These metal plates mounted about inch apart from each other on a rode or central which rotates at s speed of 7000 rpm. Magnetic disks are the most popular media for direct access secondary storages. Each disk consists of a no.of invisible concentric circles called tracks. A set of corresponding tracks in all the surface is caused cylinder.

Each track is further sub- divided into sectors. Magnetic headers are placed on surface and bottom of each plate.

Magnetic Tape: It is a sequentially accessed and processed storage media. It is a tape is plastic ribbon usually ½ inch and that is coated on one side with an iron- oxide material which can be magnetize. It is similar to a tape use on a tape-recorded. It is higher quality and more durable. Computer can be erased & re – used indefinitely.

Advantages of Magnetic Tape:

1.        Unlimited storage
2.        High data density
3.        Low cost
4.        Ease of handling
5.        Portability

      Limitations of Magnetic Tape: Not direct access

Differentiate between magnetic tape and Magnetic disk:

Magnetic Tape               Magnetic Disk

Sequential                    Random

Longer period               Shorter period

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