13 Oct
2007
13 Oct
'07
2:13 a.m.
Chuck Guzis wrote:
On 12 Oct 2007 at 23:02, Brent Hilpert wrote:
Can't remember where I read it, but it seemed plausible for the time the 4004
was being developed (1970), also that it was compounded by management's perceptions
that the 4004 was a little business on the side and not willing to invest much
in it, memory chips still being the focus. On the other hand, I wonder what
packages the original Busicom designs utilised - that Intel would otherwise have
been obligated to produce - one would expect, or typically, they would be larger.
(The 4040 would go to a larger package, of course.)
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.
Perhaps not speed as an issue but you were wired into the small family of
chips that understood the highly specific machine/bus cycle, at least
until the 4008/9 came along that broke out the address/data busses.
While the 8080 wasn't multiplexed, the 8085 was,
as was the
8086/8088. I don't think it was thought to matter.