The 4004 is not an ancestor of x86 even though the part numbers make it seem so. The 4004 was s 4-bit processor designed for calculators, and is different from

The 4004 is not an ancestor of x86 even though the part numbers make it seem so. The 4004 was s 4-bit processor designed for calculators, and is different from x86 in almost every way. The 4004 isn't even a von Neumann architecture; it has separate data and instruction memory. The 4004 has weird instructions like KBP (Keyboard Process) to decode a calculator keyboard. I/O is done through RAM ports , not memory-mapped I/O, but I/O ports built into the RAM chips! The origin of x86 is the Datapoint 2200, a desktop computer built from TTL chips. Datapoint contracted Intel to build a single-chip version of the 2200's processor, and Intel built the 8008, which was essentially a clone. Datapoint decided not to use the chip and gave the rights to Intel and the rest is history. Intel improved the 8008 to get the popular 8080 microprocessor. Intel then created the 8086, which was a 16-bit processor loosely based on the 8080. From that, the x86 architecture developed. Many features of x86 can be mapped back to the Datapoint 2200, such as little-endian.