Generation of Computers:

The first electronic computer was designed and built at the University of Pennsylvania based on vacuum tube technology.

Vacuum tubes were used to perform logic operations and to store data.

Generations of computers has been divided into five according to the development of technologies used to fabricate the processors, memories and I/O units.

I Generation: 1945 – 55

II Generation: 1955 – 65

III Generation: 1965 – 75

IV Generation: 1975 – 89

V Generation: 1989 to present

First Generation:

ENIAC - Electronic Numerical Integrator and Calculator

EDSAC – Electronic Delay Storage Automatic Calculator

EDVAC – Electronic Discrete Variable Automatic Computer

UNIVAC – Universal Automatic Computer IBM 701)

1. Vacuum tubes were used – basic arithmetic operations took few milliseconds Bulky.

2. Consume more power with limited performance

3. High cost

4. Mainly used for scientific computations.

Second Generation:

(Manufacturers – IBM 7030, Digital Data Corporation’s PDP 1/5/8 Honeywell 400)

1. Transistors were used in place of vacuum tubes. (Invented at AT&T Bell lab in 1947)

2. Small in size

3. Lesser power consumption and better performance

4. Lower cost

5. Increasingly used in business, industry and commercial organizations for preparation of payroll, inventory control, marketing, production planning, research, scientific & engineering analysis and design etc.

Third Generation:

(System 360 Mainframe from IBM, PDP-8 Mini Computer from Digital Equipment Corporation)

1. ICs were used

2. Small Scale Integration and Medium Scale Integration technology were implemented in CPU, I/O processors etc.

3. Smaller & better performance

4. Comparatively lesser cost

5. Faster processors

6. In the beginning magnetic core memories were used. Later they were replaced by semiconductor memories (RAM & ROM)

7. Introduced microprogramming

8. Database management, multi-user application, online systems like closed loop process control, airline reservation, interactive query systems, automatic industrial control etc. emerged during this period.

Fourth Generation:

(Intel’s 8088,80286,80386,80486 .., Motorola’s 68000, 68030, 68040, Apple II, CRAY I/2/X/MP etc)

1. Microprocessors were introduced as CPU– Complete processors and large section of main memory could be implemented in a single chip

2. CRT screen, laser & ink jet printers, scanners etc. were developed.

3. LAN and WANS were developed (where desktop work stations interconnected)

4. Introduced Graphical User Interface

5. Less power consumption

6. High performance, lower cost and very compact

7. Much increase in the speed of operation

Fifth Generation:

(IBM notebooks, Pentium PCs-Pentium 1/2/3/4/Dual core/Quad core..  SUN work stations, Origin 2000, PARAM 10000, IBM SP/2)

1. Generation number beyond IV, have been used occasionally to describe some current computer system that have a dominant organizational or application driven feature.

2. Computers based on artificial intelligence are available.

3. Computers use extensive parallel processing, multiple pipelines, multiple processors etc.

4. Introduced World Wide Web. (and other existing applications like e-mail, e Commerce, Virtual libraries/Classrooms, multimedia applications etc.)

5. New operating systems developed – Windows 95/98/XP/…, LINUX, etc. Got hot pluggable features – which enable a failed component to be replaced with a new one without the need to shutdown the system, allowing the uptime of the system to be very high.

6. The recent development in the application of internet is the Grid technology which is still in its upcoming stage.

7. Quantum mechanism and nanotechnology will radically change the phase of computers.