0A Computer is an electronic device that can be instructed to carry out an arbitrary set of arithmetic or logical operations automatically.
1. Introduction:
i. Speed: The speed of computation is very high as the signals pass at the speed of light. Thus, millions of calculations can be done in a second.
ii. Accuracy: As computers work on inbuilt software programs, there is no scope for human errors and are hence, highly accurate.
iii. Information and Storage: A computer can store a large amount of data or instructions in its memory which can be retrieved at point of time.
iv. Other characteristics include: Consistency, Automatic Operation, and Flexibility.
2. Characteristics of Computers:
i. Father of Computer: Charles Babbage
ii. Father of Modern Computer Science: Alan Tuning
iii. First Un-programmable Electronic Digital Computer: Atanasoff Berry Computer (ABC)
iv. First Purpose Electronic Digital Computer: Electronic Numerical Integrator and Calculator (ENIAC)
3. Generations of computers:
a. First Generation (1946 - 1959):
i. Used vacuum tubes & batch processing OS
ii. Machine & Assembly Languages used
iii. Examples: ENIAC, EDVAC, UNIVAC, IBM-701, IBM-650
b. Second Generation (1959 - 1965):
i. Used transistors.
ii. OS: Multi-Bag remaining, Time sharing.
iii. Memory: Magnetic cores, magnetic tapes and disks.
iv. Used assembly and high-level languages like FORTRAN, COBOL, Algol.
v. Examples: IBM 1620, IBM 7094, CDC 1604.
c. Third Generation (1965 - 1971):
i. Used ICs
ii. OS: Remote processing, Time-sharing, Real-time,
iii. Multi-programming
iv. Used High-level languages FORTRAN-II TO IV, Cobol, Pascal PL/1, Basic, Algol-68
v. Examples: IBM-360 series, Honeywell-6000 series, PDP, IBM-370/168
d. Fourth Generation (1971 - 1980):
i. VLSI Circuits Used.
ii. Memory: Semiconductor and Winchester disk.
iii. High level Languages: Fortan 77, Pascal, Cobol used.
iv. Examples: DEC 10, STAR 1000, PDP 11, Super Computers (CRAY-1, CRAY-X-MP).
e. The present generation of computers is the Fifth Generation of computers, i.e. 1980 – till date. The computers use ultra large scale integration (ULSI).
f. High level languages like C++, Java, .NET, etc. are used. Some examples are: laptop, desktop, ultrabook etc.
