Computer Generations and Classifications

7/27/2019 Computer Generations and Classifications

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Computer Generations and

Classifications

First generation

Second generation

Third generation

Fourth generation

Moores law

Classification of computers

By Trupti V.G,Asst. Prof, PESIT

BY PRADYUMNA S A


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First generation of computers

First electronic computer- 1946 by a team Eckert andMauchly. It was called Electronic Numerical

Integrator and calculator (ENIAC)

Vacuum tube switching devices and small memory.

Stored programming- John Von Neumann.

EDSAC(Electronic Delay Storage Automatic

Calculator)- 1st computer that used stored

programming concept Table 1


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Second generation of computers

Invention of transistors made of germanium

semiconductor material.

When compared to vacuum tubes:

They were reliable since they had no filaments to burn.

Less space and power. 1/10thpower of tubes.

Switching from 0 to 1 was faster.

Cheaper than vacuum tubes.

Magnetic cores for storage- tiny rings made of

ferrite

Table 1


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Third generation of computers

Germanium transistors replaced by silicontransistors.

Integrated circuits ICs consisting oftransistors,

resistors, capacitors grown on a single chip ofsilicon and wired interconnection between

components.

Main memory size reached 4MB


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Fourth generation of computers

Advent of microprocessor chip

Magnetic core was replaced by semiconductor

memories.

semiconductor memories-16MB.


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Moores Law

1965: George E. Moore predicted on data

available at that time, that the density of

transistors in integrated circuits will double at

regular intervals of around 2 years.

The prediction was found to be accurate.

The number of transistors per integrated circuit

chip has approximately doubled every 18 months,

this observation has been called Moores law.


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In 1970 there were around 1000 transistors placed in an

integrated chip whereas now there are nearly 1 billion

transistors are placed in a chip and still the researches are

going on to increase the number.


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Classifications of computers

Pocket or hand held PCs:

Used as Fax, mobile phone. OS: Windows CE

Simputer: Simputer is a mobile handheld

computer.

Open source OS: Linux

Laptop PCs: less power, portable

Personal Computers: Desktop machines


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Workstations: Processor speed is 10 times more than PCs. High end computers for scientific applications.

They are commonly connected to a local area network.

Workstations offered higher performance than desktopcomputers, especially with respect to CPU and graphics,

memory capacity, and multitasking capability. Operating system: UNIX

Servers: Systems that provide services.

They are used for specific purposes such as high performancenumerical computing, web page hosting, e-mail service,database store

Usually connected to network.


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Thin clients:

It is a computer or a computer program which depends

heavily on some other computer (its server) to complete

its task.

its a terminal to access a server(s).

Advantages:

Cheaper than desktops

software cost is lower as they do not have native OS, virus

protection and application software.

Disadvantage:

Dependence on network,

Cannot be used as independent computer


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Mainframe computers:

Are computers used primarily by corporate and governmental

organizations for critical applications, bulk data processing suchas census, industry and consumer statistics, enterprise resource

planning, and transaction processing.

Expensive

Faster and larger than workstations Manufacturers of mainframes: IBM, Hitachi

Operating system: extensive service such as user

accounting, file security, control. They are reliable

compared to PCs. Ex: z/OS


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Supercomputers:

They are fastest computers used for intensive numerical

calculations.

are used for a wide range of computationally intensive

tasks in various fields, including quantum

mechanics, weather forecasting, climate research, oil and

gas exploration, designing aircrafts

Documents

Computer Generations and Classifications