OR> 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)