Intel started the x86 business a long time ago in 1971 with the
4004. This processor was designed for Nippon Calculating Machine Corporation.
It ran at a speed of 0.108 KHz and had a 4 bit design. This processor
was slow even in that time, but it was cheap to manufacture. At a point
Intel bought the rights for design of the 4004 back from NCMC. They could
now sell the 4004 to other parties and develop the design further.
The next processor Intel designed was the 8008. This micro processor
ran at 0.5 MHz and was, like the 4004, designed esspecially for a customer.
The 8008 was to be used in a server from Computer Terminals Corporation,
but CTC decided that the chip was to slow. Intel then marketed chip themselves
and continued to enhance the design.
But the processor that really started the Personal Computer business
was the 8080! Four people designed the chip in about 1 year. Ted Hoff
and Stan Mazor were responsible for the instruction set, and Federico
Faggin and Masatoshi Shima were responsible for the circuit layout. The
processor had 78 instructions and the 8080A ran at 2 MHz. At that speed
this cpu was about 10 times faster than the 8008. Unlike the 4004 and
the 8008, Intel did not design the chip for a special customer. Strengthend
by the succes of the 8008 they believed they could market the chip themselves,
and they succeeded.
Soon after the introduction, the 8080 became a huge succes and
was implemented in a wide variety of products. A big contribution to the
popularity of the processor was made by the Altair8800 who used the 8080
micro processor. The Altair8800 is generally seen as the first PC. Because
of the overnight succes of the Altair other manufacturers wanted a piece
of the succes and also based their product on the Intel made 8080. Products
like the IMSAI 8080 but also Terminals and according to the Intel website
even traffic light controllers used the 8080 micro processor!
The 8080 was essentially an enhanced version of the 8008. It had
more signal inputs and outputs and was therefor faster. It was however
backwards compatible with the 8008, so software written for the 8008 could
be run on an 8080. The chip had an 8 bit design and was packaged in a
40 pin CERDIP or DIP module.
This processor was in demand and cheap to manufacture, many other
IC manufacturers copied the design and manufactured 8080's. Mitsubishi,
Siemens, National Semiconductors, AMD and Texas Instruments all produced
8080's. Many without the consent of Intel, only Siemens, and later AMD,
were authorised by Intel to do so. 8080's manufactured by AMD were named
AM9080, National Semiconductors named them INS8080 and Mitsubishi M5L8080.
enhanced the 8080 further and marketed the enhanced version of the chip
as the 8085. This micro processor had 6.500 transistors and was manufactured
at 3 microns. The design changes allowed for a higher speed, it ran at
up to 6 MHz. The 8085 was software compatible with the 8080 but not pin