26-04-2012, 02:56 PM
Computer history and evolution
02_Computer Evolution and Performance.ppt (Size: 330.5 KB / Downloads: 47)
First generation (vaccum tubes)
Electronic Numerical Integrator And Computer -ENIAC
Designed by John Eckert and John Mauchly at University of Pennsylvania
Generally regarded as first electronic computer
Started 1943
Finished 1946
Used until 1955
von Neumann Machine(IAS)
Developed the concept of Storing Program in memory (stored program concept)
In 1946 at Princeton Institute for Advanced Studies, IAS was started.
It consisit of:
Main memory ,which stores both data and instructions.
ALU operating on binary data
Control unit interpreting instructions from memory and executing
Input and output equipment operated by control unit
Structure of IAS – detail
MBR: Contains a word to be stored in memory or sent to I/O
MAR: contains the address of word in MBR
IR: contains 8 bit opcode instruction being executed
IBR: use to hold right hand instruction from a word in memory
PC: contains the address of next instruction to be executed
AC and MQ : used to hold temporarily operands and result of ALU.