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Politics : Formerly About Advanced Micro Devices -- Ignore unavailable to you. Want to Upgrade?

To: i-node who wrote (620378)	7/21/2011 6:28:35 AM
From: Taro	Read Replies (1) \| Respond to of 1578196

By 1980 most likely any low cost system running PDP-8 software was based on the IM6100 micro processor from Intersil. It did indeed fully emulate PDP-8, was low cost CMOS, which also made it a power miser. The IM6100 hit the market around 1976. Actually a wealth of standard programs were freely available for the PDP-8 back then and a lot of that was pro level quality. But the PDP-8 was not very user friendly based on octal rather than hex bytes and mnemonics. Interestingly enough, when Busicom, Japan bellied up and the Intel 4004 chip set (credited for being the first micro processor) developed by Ted Hoff as a programmable custom chip set for their desk top calculator, thus no longer had a home, Bob Noice got the brilliant idea of trying to sell it on the open market. Intel then hired some ex DEC guys to develop the documentation required for that effort. These guys, still thinking in PDP-8 octals then introduced a set of mnemonics for the I 4004 - based on octals! Now as we probably all know, the 4004 was a 4 bit machine. Thus each clock cycle moved a 4 bit word through the registers. Applying octal size mnemonics to this environment of course was total madness. Consequently this Intel first micro processor marketing effort was a total failure. But not quite, because around the world a handful of creative engineers saw the possibilities in using this chip as the heart of various automatic equipment. They analyzed the architecture, skipped those fat manuals from Intel and developed their own set of hex mnemonics. The rest was easy, because the structure of the 4004 was very regular. No interrupts, just a 4 level deep JMS stack to store the data when going to a subroutine and - voila! The 4004 was extremely easy to program and it was back then done using flow charts and writing the program in mnemonics on a long pice of paper. No assemblers or compilers, just plain engineering well documented routine work needed. And Intel listened to and learned from their initial customers, and as they say, the rest is history. That's actually the story behind how Intel invented the microprocessor. And here one of my favorite quotes, "Very much in history very nearly didn't happen" (anonymous). /Taro