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.