from
The Free On-line Dictionary of Computing (8 July 2008)
Intel 4004
<processor> The world's first {microprocessor}, released in
1971. The 4004 contained 2300 transistors (compared with 5.5
million in the 1996 {Pentium Pro}) and was intended for use in
a calculator. It processed data in 4 bits, but its
instructions were 8 bits long. Program and Data memory were
separate, it had 1 {kilobyte} of data memory and a 12-bit {PC}
for 4K of program memory (in the form of a 4 level {stack},
used for CALL and RET instructions). There were also sixteen
4-bit (or eight 8-bit) general purpose {registers}. The 4004
had 46 instructions.
(1997-03-30)