4004/4040 Microprocessor Family: The Intel MCS-40 family includes the first microprocessor ever invented - the 4004. The 4004 was introduced as a pMOS device. The 4040 is an enhanced version of the 4004. The 4040 has 60 instructions (4004 has 45 instructions) and has expanded stack (7 levels instead of 3) and scratchpad areas (24 instead of 16). All 4004 code instructions can be run on a 4040 system.