Classification of Computers

Classification of Computers According to Purpose

1) General Purpose ComputersDesigned to perform a range of tasks.Ability to store numerous programs.Used for various application, Ranging from scientific to business

purpose.Versatile but lack in speed & efficiency.Ex: Computers used in schools and home.2) Specific Purpose ComputersDesigned to handle a specific problem or to perform specific task.A set of instruction is build into the machine for that specific task.Cannot be used for other application unless its circuits are

redesigned.Lacked in versatility but can provide result very quickly and

efficiently.Ex: Computers used for airline reservation, Satellite tracking or air

traffic control.

Classification According to Type of Data Handling Technique

1) Analog Computers• Works on the principle of measuring, in which

the measurements obtained are translated.• Do not directly deals with numbers, Measures

continuous physical magnitude (temp, pressure, Voltage).

• These computers are very fast in operation but lack in accuracy.

• Example: Analog computer in petrol pump that converts flow of petrol into quantity and price.

2) Digital Computers• Operates with information represented in digital

form.• Process data(Text, sound, graphics, video) into a

digital value ( 0 & 1).• Analog quantities must be converted into digital

before processing.• In this case output is also digital but if desired can be

converted into analog quantity.• Accuracy of these computers depends upon size of

their registers and memory.• Example: Desktop PC

3) Hybrid Computers• Incorporated the measuring feature of analog

computer and counting feature of digital computer.

• These computers use the analog components for computational purpose and to store the immediate result it uses digital memories.

• The hybrid computer uses the converter (Digital to analog & Vice-versa) in order to bind the powers of digital and analog techniques.

• Used for scientific application, various field of engineering, Industrial control process.

Classification According to Functionality• Based on size, performance and application

areas.1) Micro computers• Small and low cost digital computer, Usually

consist of a micro-processor, a storage unit and output channel.

• Examples: IBM-PC, APPLE etc

• Desktops:Most common micro computer consist of system unit, monitor, keyboard, hard-disk & other peripheral devices.

Classification According to Functionality

• Laptop:Portable computer enclosing all the basic features of a normal desktop computer.The biggest advantage is that one can carry and use this computer anywhere.Laptops do not any external power supply.

• Hand-Held ComputersPDA is a computer that can easily stored in a pocket.It generally uses a pen or electronic stylus as input device.Usually have no disk drive, It uses small card to store program and data.

2) Mini Computers• Small digital computer, which

normally able to process and store more data than micro computers.

• Size of mini computer is bigger than micro computer.

• Designed to meet computing needs of small and medium size business environment.

• Support 4 to 200 users simultaneously.

• Ex: PDP11, IBM8000 series.

3) Main frame computersUltra high performance computer made for complex

computing.It consist of a high-end computer processor with related

peripheral devices.Capable of supporting large volume of data processing, high

performance on-line transactions processing system and extensive data storage & retrieval.

It is designed to perform faster and store more data than mini computer.

Usually executes many programs simultaneously with high speed.

Allows users to maintain large information storage at a centralized location and be able to access and process this data from different computers located at different locations.

Typically used for large business and scientific purpose.Ex: IBM’s ES000, VAX 8000, CDC 6600.

4) Super computers• Special purpose machines, which are specially

designed to maximize the efficiency.• A super computer has the highest computing

speed for solving scientific and engineering problems.

• It contains a number of CPUs that operate in parallel to make it faster.

• It can process large amount of information and make extensive calculation quickly.

• Super computers are fastest, costliest and most powerful computers available today.

• Ex: CRAY-3, Cyber 205, PARAM

Workstation• A workstation is a high-end microcomputer

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 systems.

• The term workstation has also been used to refer to a mainframe computer terminal or a PC connected to a network.

Server• A server is any combination of hardware or

software designed to provide services to clients.

• Process that shares a resource to one or more client processes is a Server.

• Example: 1)File sharing2) web server