22 May
2013
22 May
'13
11:27 p.m.
On 05/22/2013 04:03 PM, Phil Budne wrote:
I was just at the Living Computer Museum in Seattle, I
saw a PDP-8, an
Altair and an Imsai, and I couldn't help thinking how much alike they looked.
And since the Altair is in the running for the title of the first
commercial Microcomputer, it's not surprising someone would have used
an older term to describe it.
"Microcomputer" was an evolutionary term. Remember that, in 1973, you
had both multi-chip CPUs (e.g. National IMP-16 set) in addition to the
single-chip (e.g. 8008) CPUs, although calling an 8008 a single-chip CPU
might still be considered by some to be a stretch, given the amount of
support logic required. So, while a single-chip CPU was considered to
be evolutionary back then, the significance was mostly recognized by the
technical types in the IC business.
I seem to recall that in 1969-70, the SN74181 was viewed as a major step
forward and the speculation began about putting a whole CPU on a chip.
I remember conveying the excitement to some friends in the business who
didn't see the significance of a single-chip CPU, particularly given the
speed of MOS logic back then--a whole bipolar CPU on a chip was viewed
as a more remote target, owing to fabrication and power issues. MOS had
the edge for rather complex circuits, especially for things such as
shift registers and whatnot.
At least that's what I remember. What *was* the first bipolar CPU on a
chip--would that have been the SMS-300? I'd probably call it more of a
microcontroller, but maybe that's splitting hairs. TI had their I2L
version of the TMS9900, but that was somewhat later.
--Chuck