4004 and IC history / was Re: Vintage computer photogallery
dkelvey at hotmail.com
Sat Oct 13 09:46:51 CDT 2007
> From: cclist at sydex.com> > On 12 Oct 2007 at 23:02, Brent Hilpert wrote:> > > Can't testify to it's accuracy but one of my favorite quips about the 4004> > is the reason it had that multiplexed 4-bit bus/machine cycle was to squish> > it into a 16-pin package because management didn't want to tool up for larger> > packages.> > Sounds like an urban legend to me. 24-pin packages were around in > the Intel line then, I believe. In any case, the 8008 followed suit > with an 18-pin package. I suspect that multiplexing didn't matter > much to the overall speed of the thing.
This was what Federico Faggin had stated at a talk he gave at the CHM.
Packaging was expensive and they'd made volume deals on 16 pin
packages. Faggin stated that his design could have been a few times
faster had he not been restricted to the small bus.
> > While the 8080 wasn't multiplexed, the 8085 was, as was the > 8086/8088. I don't think it was thought to matter.
The 4004/4040 had an 8 cycle muxing of the bus. The later ones
were just two cycle. Package size was always a dominating
cost and defined many projects.
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