Computer Overview

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Computer Overview

Introduction:-

Computers have made great inroads in our everyday life and thinking. They are put to use for all sorts of application ranging from complex calculation in the field or frontline research, engineering simulations down to teaching, printing books and recreational games. The ease with which computers scan process data, store and retrieve it painlessly has made them inevitable in office and business environments. The areas of applications of computers are confined only by limitations on human creativity and imagination. In fact, any task that can be carried out systematically can be performed by computer. Therefore, it is essential for every educated person today to know about a computer.

What is Computer?

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A computer is an electronic device that can perform a variety of operations in accordance to a set of instructions called program.

Computers can access and process data millions of times faster than humans can. A computer can store data and information in its memory, process them and produce the desired results. Computers can do a lot of different tasks such as weather forecasting, playing games, error detection, railway reservation etc.

A computer is essentially as a data processor. The terms data and information are very commonly used. Data are raw facts whereas Information is meaningful data.

Functional component of a Computer:-

Since a computer follows input-process-output cycle. The first stage is performed in computer by input unit; second stage is performed by its central processing unit and the third stage is stage performed by output unit.

Hardware and Software:-

Hardware represents the physical and tangible components of the computer i.e. the components that can be seen and touched. Or we can say that collectively, the electronic, electrical and mechanical equipment that makes up a computer is called computer. Input devices, Output devices, CPU, hard disk etc. are all examples of computer hardware.

Software represents the set of programs that govern the operation of a computer system and make the hard ware run.

Software can be classified broadly into three categories:

• Operating System
• Language Processor
• Application Software

Together operating system and language processor are known as system software.

Operating System:-

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An operating system is a program which acts as an interface between a user and the hardware (i.e. all computer resources) and controls all other components of the computer system.

Operating system is just like our secretary. As the boss gives orders to his secretary and secretary does all the work for his boss. The secretary himself decides: How to do?; What to do?;When to do?;etc. Same way we pass our orders and operating system does it for us.

Example: Windows, Linux, UNIX etc.

Language Processors:-

The system programs which convert High-level language into Low-level language are known as Language processors.

The language processors are given below:

• Assembler.
• Interpreter.
• Compiler.

Strengths and Weaknesses of a Computer:-

The strengths of a Computer are:

• Speed
• High Storage Capacity
• Accuracy
• Reliability
• Versatility

The weaknesses of a Computer are:

• Lack of Decision Making Power
• IQ Zero

The generation of Computers:-

• First Generation (1940-1956) – Vacuum Tubes
• Second Generation (1956-1963) – Transistors
• Third Generation (1964-1971) – Integrated Circuits
• Fourth Generation (1971-Present) – Microprocessors
• Fifth Generation (Present-Beyond) – Artificial Intelligence

Evolution of Storage technologies:-

The electronic revolution started from 18^th-19^th century and changed the human life forever. The associated data storage technologies also evolved with computer evolution. Let us how these storage technologies evolved over time.

• Machine-Readable Punched Card (1890)
• Magnetic Drum (1932)
• Magnetic Tape (1951)
• Hard Disk Drive (1958)
• Floppy Disk (1969)
• Optical Storage Media – CD (1980s), DVDs (1990s)
• Flash Drive (1998)
• Blue-Ray Discs (2000)
• The Cloud (21^st century)

Evolution of Display technologies:-

• CRT-Cathode Ray Tube (1897)
• LCD-Liquid Crystal Display (1963)
• Plasma Monitors (1964)
• Touchscreen Monitors (1965)
• OLED-Organic Light Emitting Display (1987)

Evolution of Programming language:-

• 1^st Generation Programming Language (1GL)
• 2^nd Generation Programming Language (2GL)
• 3^rd Generation Programming Language (3GL)
• 4^th Generation Programming Language (4GLs)
• 5^th Generation Programming Language (5GLs)

Evolution of Software Application:-

• Command Line Programs (1980s) –The first generation software applications included compilers, device-drivers etc.
• Desktop Applications (1990s) – With the popularity of graphical interface, GUI based desktop applications of multiple types and forms were released: Office Applications, Audio and Video players, Utility programs, Browsers etc.
• Web Applications (21^st Century) – Most popular web applications include Email clients like Gmail etc.; Social networking platforms like Facebook, Twitter, Instagram, Pinterest, Quora etc.; VoIP Programs like Skype etc. and many more.
• Mobile Applications (21^st Century) – The popular Mobile Application development platforms are iOS, Android, Windows, which are also the most popular mobile operating systems.

Types of Computers:-

Purpose Wise

• Special purpose Computers – A special purpose computer is the one that is designed to perform a specific task.
• General purpose Computers – A general purpose computer is the one that can work on different types of programs input to it and thus be used in countless applications.

Principle of Operation Wise

• Analog Computers – These computer types work with continuous physical quantities such as voltage, current, temperature etc. But their accuracy is poor. Analog computers are mostly used in engineering and scientific applications. An electronic weighing scale is an example of an analog computer.
• Digital Computers – These computer types work with discontinuous data converted into binary form i.e. digits 0 and 1 and all operations are carried out on these digits at extremely fast rates. Computers are much faster than analog computers and far more accurate. These computers are used for business and scientific applications.
• Hybrid Computers – Hybrid computers utilize the best qualities of both the digital and analog computers. In these computers some calculations take place in analog manner and rest of them take place in digital manner. Hybrid computers are best used in hospitals to monitor patient’s vital signs. Hybrid computers are also used for weather forecasting.

Types of Digital Computers:-

• Embedded Computers – These computers are in the form of tiny chips embedded within the circuit of appliances such as televisions, washing machines and wrist watch etc.
• Personal Computers (PCs) – These are mainly used in offices, homes, schools, shops, stores etc. IBM PCs, Apple Mac, IBM PS/2 are some popular computers of this range.
• Minicomputers – Minicomputers are mainly multiusers system where many users simultaneously work on the system. Examples are PDP-11, VAX and 7500 MAGNUM etc.
• Mainframe Computers – These computers are designed to handle huge volumes of data and information. These are very large and expensive computers have great processing speed and very large storage capacity and memory. Examples are ICL 39, CDC 6600, VAX 8842, IBM 3090/600 and IBM 4381.
• Super Computers – These computers are the most powerful computers among digital computers. These consist of several processors running together thereby making them immensely faster and powerful. Examples are CRAY X-MP-14, CDC-205, ETA GF-10, FUJITSU VP-400, NEC SX-2, PARAM and PACE.

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