Re: 11 most influential microprocessors of all time

[Michael Black <et472@ncf.ca>]

On Wed, 2 Sep 2009, Eric Rucker wrote:

> On Sep 2, 11:06 pm, "Michael J. Mahon" <mjma...@aol.com> wrote:
> > PA-RISC shook up the industry in the 1990s, by pushing performance
> > harder than most thought possible.  And it was the major factor in
> > catapulting HP into the server and high performance workstation markets.
> >
> > Unfortunately, having done its job, it's largely retired now...but
> > it was a heck of a run!
>
> More to the point, how did PA-RISC influence the marketplace in the
> long run?
>
> In the long run, PA-RISC got killed in favor of Itanium, and it was
> all but forgotten about.
>
> Every single chip on that list except for possibly COSMAC and the 8088
> strongly influenced the marketplace in some way. 4004 for being the
> first, 8080 for making microprocessors practical at all for home
> computers, 6502 and Z80 for making them cheap, 68000 for making
> personal computers with GUIs practical, Pentium for marketing the CPU
> rather than the computer, and ARM and PPC for ramming themselves
> deeply into the embedded space. The 8088 was lucky (whatever was in
> the IBM PC would have probably dominated the market, therefore, the
> 8088 wasn't what was influential,) and the COSMAC... yes, it was in a
> well-known embedded application, but what else did it really do for
> the market?
The 1802 was one of the few CPUs back then that was able to stand up
to the radiation it would see in space.  So it's not just one famous
space probe, but it was key to a lot of space junk back then.  It was
in one of the amateur satellites, not OSCAR 6 (which went up in the
fall of 1972) but maybe OSCAR 7.

Another reason it was valuable up there was a reason it was a hot
commodity as a kit for the hobbyist.  It had a pin that would put it
in a mode that would single step through the address range, which
then made it so much easier to load up the RAM.  Other CPUs required
quite a bit of extra hardware, the 1802 made it easy.  So for
the hobbyist, it meant being able to get a computer going without
a monitor or extensive hardware, and for the satellite builder, it
meant being able to load new software in from earth without using
up address space for ROM to load in the new software.  If the contents
of the RAM got wonky, it was still capable of having fresh software
reloaded from earth.  I assume that was also a feature in the fancy
space hardware and not just the amateur satellite.

The 4004 was barely useable.  It was satisfactory for what it
was designed for, a logic replacement, but not much as an actual
computer.  When the 8008 came along, it was a real computer in an
IC.  The fact that later CPUs were much better is irrelevant, since
at the time of the 8008, there wasn't anything else.  People forget
that Scelbi had an 8008 computer sometime in 1974, and of course
the Mark-8 that was 8008 based was on the cover of Radio Electronics
for August 1974.  Presumably there was a lot more activity over
the 8008 than most of us actually saw.  So one could presumably
argue that the reception that the 8008 received ensured that
other CPUs would follow.  A different turn of events might have
said "no, let's stick with logic, an IC CPU isn't what we need....".

What people forget is how much happened in just a few years.  Massive
change, even if each CPU was pretty primitive.  So it went from the 4004
in 1971 to the 6502 and the Z80 in 1975.  Godbout had a contest in about
the first issue of Byte (September 1975) for people to guess which
16bit CPU they were putting in their new computer.  It was the National 
Pace, and Godbout never went through with such a computer, but it just
shows that it went from a 4bit barely useable CPU in 1971 to the point of 
multiple CPUs, including at least one 16bit, in 1975.  That's massive
and rapid change, and each new development was a bold step forward.

Then it got cluttered, lots of CPUs that ended up as also-rans.  In
some cases because there wasn't anything great about the CPU, in
other cases maybe bad marketing or that by then enough user base
had built up on a few CPUs that few were interested in the work
involved in going another route.  The 6800 and then the 6502 brought
something new to a market that had few choices, but then a year or
even months later things had solidified and it didn't matter that
your CPU was "so much better", too much work had been put into
the handful of CPUs that had success to bother with something new.

The 6809 came along some years later, and it was too late.  THings
were solidified by things like CP/M so a "foreign" cpu was not
appealing, except if it was 16bit which was a big leap forward.  There
was the Intersil 6100 (I think that was the number), which was compatible 
with the PDP/8, ie a 12 bit CPU.  But the only real market was if you'd
invested in software for the PDP/8, otherwise there was little appeal.

After a bit, it didn't matter what else was available, few were 
interested. So after a while, there were fewer CPUs that could
make an impact.

After about 1980, there was a lot less innovation, because everyone
wanted to be compatible with the past.  Things have changed drastically
since then, yet at the core is mostly what was there back then.

  Michael