20-06-2013, 02:27 PM
STUDY MATERIALS ON COMPUTER ORGANIZATION
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INTRODUCTION
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)
Vacuum tubes were used – basic arithmetic operations took few milliseconds
Bulky
Consume more power with limited performance
High cost
Uses assembly language – to prepare programs. These were translated into machine level language for execution.
Mercury delay line memories and Electrostatic memories were used
Fixed point arithmetic was used
100 to 1000 fold increase in speed relative to the earlier mechanical and relay based electromechanical technology
Punched cards and paper tape were invented to feed programs and data and to get results.
Magnetic tape / magnetic drum were used as secondary memory
Mainly used for scientific computations.
TYPES OF COMPUTERS
1. Super Computers
2. Main Frame Computers
3. Mini Computers
4. Micro Computers
1. Super Computers
E.g.:- CRAY Research :- CRAY-1 & CRAY-2, Fujitsu (VP2000), Hitachi (S820), NEC (SX20), PARAM 10000 by C-DAC, Anupam by BARC, PACE Series by DRDO
Most powerful Computer system - needs a large room
Minimum world length is 64 bits
CPU speed: 100 MIPS
Equivalent to 4000 computers
High cost: 4 – 5 millions
Able to handle large amount of data
High power consumption
High precision