The 8086 (also called iAPX 86) is a 16-bit microprocessor chip designed by Intel between early 1976 and mid-1978, when it was released. The 8086 gave rise to the x86 architecture of Intel's future processors. The Intel 8088, released in 1979, was a slightly modified chip with an external 8-bit data bus (allowing the use of cheaper and fewer supporting logic chips), and is notable as the processor used in the original IBM PC.
In 1972, Intel launched the 8008, the first 8-bit microprocessor. It implemented an instruction set designed by Datapoint corporation with programmable CRT terminals in mind, that also proved to be fairly general purpose. The device needed several additional ICs to produce a functional computer, in part due to its small 18-pin "memory-package", which ruled out the use of a separate address bus (Intel was primarily a DRAM manufacturer at the time).
Two years later, in 1974, Intel launched the 8080, employing the new 40-pin DIL packages originally developed for calculator ICs to enable a separate address bus. It had an extended instruction set that was source- (not binary-) compatible with the 8008 and also included some 16-bit instructions to make programming easier. The 8080 device, often described as the first truly useful microprocessor, was eventually replaced by the depletion-load based 8085 (1977) which could cope with a single 5V power supply instead of the three different operating voltages of earlier chips. Other well known 8-bit microprocessors that emerged during these years were Motorola 6800 (1974), General Instrument PIC16X (1975), MOS Technology 6502 (1975), Zilog Z80 (1976), and Motorola 6809 (1978).