Computer Fundamentals

Ministry of Higher Education

Bamyan University

Computer Science Department

Presented by : Mustafa Kamel Mohammadi

Email : bamian.cs@gmail.com

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Learning objective

• In this chapter you will learn about• Classification of computers

• Classification of computers based on input Data

• Classification of computers based on purpose

• Classification of computers based on size

• Client and Server computers

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Classification of Computer

• Computers are mainly classified based on different criteria• Input data and processing manner

• Based on purpose

• Based on size

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According to input data

• Based on processing Data; computers are divided into 3 categories• Analog computer

• Digital computer

• Hybrid Computer

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Analog Computers

• Analog Computer• Gets data in the form of waves, signals,……

• Are those in which data varies continuously i.e. the movement of data is continuous.

• Series of waves

• Used for• Measuring temperature, pressure, etc

• Communication

• Broadcast transmission

• Example• Automobile Speedometer, Voltmeter, etc

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Digital computers

• Are those computers in which data flows in discrete form

• Represented by: pulses, two series i.e. 0s & 1s

• Used for• Mathematical calculations

• Compare values

• Storing the result

• Example• Digital watch, Education system, business purpose

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Hybrid computers

• are combination of both analog computer and digital computer

• Measures: both continuous and discrete form of data

• Example • Measuring heart beat or ECG system in ICU in a hospital

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Classification of computers based on purpose

• In digital computer, classification can be done on the basis of purpose• General purpose computer

• Special purpose computer

• General purpose computer• These are designed to perform the variety of jobs or applications for this

reason

• They are less efficient than special purpose computers.

• Example• Banking, Sales Analysis, PCs, etc

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Cont.

• Special purpose computer• These are designed to meet the needs of some special application.

• They are designed to perform a single job.

• So they execute a task quickly and more efficiently.

• Program and instructions are stored permanently in them.

• Example• Weapon designing

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According to sizes

• Super Computer

• Mainframe Computer

• Workstation Computer

• Personal Computer

• Notebook Computer

• Pocket or handheld Computer

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Super computers

• Special purpose computers that handle mostly complex scientific, statistical applications or programs.

• Key features• High technology

• High capacity memory

• Computes data processing in short time

• Solving highly sophisticated problems• Weather prediction

• Engineering problem

• Cost varies from 1 million to 5 million

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Cont.

Cont.

• Drawback• Operating Supercomputer requires highly qualified staff.

• Experts were required for such computer engineering.

• They are sensitive to temperature, humidity, dust, etc.

• Non portability & large size

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Mainframe Computers

• Key features• Mainly used by large organizations such as banks, insurance, companies,

hospitals, railways,…

• Smaller size than super computer

• Large memory capacity

• Used to share common computing facilities

• Allows networking with to many terminals

• Cost varies from hundreds of thousand dollars

• Disadvantages• Experts and highly qualified professionals were required to operate it

• Sophisticated technology required for manufacturing & assembling the computer

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Cont.

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Workstation

• Key features• Higher processing speed than lowest category computer but slower than

super computer & Mainframe computer

• Portable computers because of smaller size

• Provide • Greater processing power

• Larger storage capacity

• Better graphic display

• Used for• Computer aided design

• Multimedia applications

• Simulation and visualization

• Usually uses unix based multiuser operating systems

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Personal computers or PC

• Non portable , general purpose computers

• Designed to meet personal computing needs

• Generally used by one person at a time but supports multi tasking

• Two common types of PC• Desktop model

• Tower model

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Notebook computers

• Portable computers used by those who need computing resources wherever they go

• Smaller size and can fit in a briefcase

• Wight around 2 or more kg

• Comfortable computers and can be placed on lap, so they are called laptop

• Designed to operate with chargeable batteries

• Used to consume little power and suspended whenever not used

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Handheld computers

• Devices that can be hold in hand

• Types are• Tablet

• Pocket PC

• Smart phone

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Handheld computers

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Client and server computer

• Client server computing environment has • Clients

• Servers

• Network

• Client is a PC/workstation with friendly user interface

• Server is generally a computer • Manages shared resources

• Provide services to clients

• Network may be a single LAN, WAN or internet

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