This document classifies computers based on their capacities, uses, size, and purpose. It discusses analog computers, digital computers, and hybrid computers. Digital computers process discrete data using binary digits while analog computers measure continuous physical variations. Hybrid computers contain features of both. Computers are also classified by size as super computers, mainframe computers, mini computers, and micro computers. Super computers are the most powerful and expensive, able to perform over a trillion calculations per second, while micro computers are general purpose, single-user computers that support networking. The document provides examples to illustrate each classification.

1. Repair & Maintenance
D.Com II/II
UNIT 2. CLASSIFICATION OF COMPUTER
LECTURE BY : ER. ASHISH K.C (KHATRI)

2. Classifications:
- Is done based on capacities and uses.
● Classification on the basis of work
● Classification on the basis of purpose
● Classification on the basis of size
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3. On the basis of work:
● Analog Computer :
- is a type of computational device in which the problem variables
are represented as continuous, varying physical quantities such as
temperature and pressure.
- are special purpose computer that perform specific task.
- are faster in operation.
- are less precise than digital computers.
- reprogramming is not possible.
- deal with changing physical quantities.
- example : Seismograph, Speedometer, etc
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4. Digital Computer:
- Is an electronic computing machine that uses binary digits 0 and 1 to
represent all forms of instruction internally in digital form.
- Works on discontinuous data.
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5. 5
Analog Computer Digital Computer
Measures continuous physical variations
such as pressure, temperature, voltage,etc
Processes discrete data’s such as numbers,
letters, etc.
Generates analog signals Generates digital signals
Low accuracy High accuracy
HIgh cost Low cost
Used for special purpose Used for general purpose
Re-programming is not possible Re-programming is possible

6. Hybrid Computer:
- Contain the features of analog and digital computer.
- Inputs analog signal convert them into digital form.
- Used in Flight management, ICU, monitor in petrol pumps,
industries, etc.
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7. On the basis of purpose:
● Specific purpose :
- designed to perform specific task only.
- most analog computers are specific purpose computers.
- reprogramming not possible.
- trained personal required to operate.
● General purpose :
- designed to perform many task.
- used generally everywhere and everyone.
- computers at home and offices are general purpose computers.
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8. On the basis of size:
● Super Computer:
- most powerful computers in the world.
- huge in size, have highest processing speed and most expensive.
- used to process large amount of data to solve complicated
scientific problems.
- can perform more than one trillion calculations per second.
- can handle thousands of users at same time.
- used in automobile industries, aerospace, meteorological, weather
forecasting, etc
- example: CRAY-1, CRAY-2, etc
Nepal’s first supercomputer has 184 CPU servers, 16 disk servers and 12 network
switches, with a total processor count of over 2,500 and 8 TB of memory.
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9. Mainframe computer:
- are larger in size, have higher processing speed.
- Have large storage capacity nad expensive than mini computers.
- Have multi processors so thousands of users can use single
mainframe computer at time.
- Are specially used as servers on the world wide web.
- Are used in banks, airlines, universities, etc
- Example: IBM 1401, CDC 6600, etc
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10. Mini Computers:
- Are medium sized computers which are more powerful than micro
computers.
- Have high processing speed and higher cost than micro computers.
- Hundreds of user can use the mini computer at a same time.
- Are commonly used as server in a network.
- Are used in business, education and many other fields.
- Example: PDP-11
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11. Micro Computer
- Are general purpose computers
- Small sized computer which use microprocessor as their CPU.
- Are single user computers because they are designed to be used by
one person at a time.
- Micro computers support networking environment, internet system
and advanced software.
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12. Types of micro computer:
● Desktop Computer
● Laptop Computer
● Handheld Computer
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13. End of Unit
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