On Thu, Jun 30, 2016 at 11:49 AM, Larry McVoy <lm@mcvoy.com> wrote:

On Thu, Jun 30, 2016 at 11:32:08AM -0400, Dan Cross wrote:
> MC68000 vs Intel 8088 seems like a no-brainer: the 68k is the superior
> chip. From a business perspective, I guess it was a very different matter,

Yup - you take what you can get. And if Moto is not doing to sell it you when you are designing a new system.

> but that's not my area and the ship has long sailed over the horizon.
> Still, it's fun to speculate and I can't help but think that a 68k-based
> IBM PC would have been a nicer machine.

+1

+1 And I suspect so many fewer problems would have ensued. At least linear addressing would have been de rigueur from day 1;-)

> Something I never understood about the IBM PC: even the 8088 machine was
> fairly beefy compared to e.g. a PDP-11/20. The 6th Edition Unix kernel was
> objectively pretty small and understandable; mini-Unix showed that that
> sort of software could be used on a machine without an MMU. I've never
> understood why IBM didn't just write a real OS in a high-level language
> instead of saddling the world with MS-DOS. Perhaps it's naive of me, but
> even if they didn't use Unix directly, it was an existence proof that such
> a thing was possible. I suppose, again, it was less a technical issue and
> more a business issue, or perhaps I'm underestimating the amount of work or
> missing some of the technical complexities.

I wonder if they just didn't know.

Possible -- ignorance of that team would have been high, certainly at the managerial layers. You might ask Guy Sotomayer who showed up in Boca soon after the release if not before it. Guy certainly knew UNIX (he was one of my lab partners at CMU) and I'm sure a number of his peers did also.

Unix was Bell Labs and Universities for

the most part.

Mumble, IBM was selling to universities and has a strong on-site presence at MIT (that's were VM came from). Boca was doing stuff with 8085s and this was "entry systems" so I think the field of view was a lot more shallow. But parts of IBM knew about UNIX and TOPS-10. One of Guy and my other lab partners was Chris Pathe', who graduated from CMU to work for IBM, but programming DEC systems for them. They hired him because he knew TOPS and UNIX, etc.

Was the timing such that they may not have been aware of
Unix? Or maybe they knew about Unix but thought it was for the vax?

Stuff I have read said that IBM wanted to compete originally with S-100 type systems with this new system. Hence the famous desire for CP/M. They always were primarily buying the SW from firms that had built SW for microprocessors. And, if I understand the history pieces that have been published, the project was financed by large systems, that wanted to system to run VisiCalc, which was a hit in financial circles. But large systems team were not doing much the SW themselves for these boxes. It >>seems<< like IBM was thinking about SW in terms of very large machines so even PDP-11's were small in those days. That said their marketing folks for the PC, put the focus on 16 bits was because they wanted to be "better" than the 8-bit 8080/8085/Z80 that was the S-100 standard or the 6502 in the Apple II. Hence, Moto pushing an 8-bit chip was rejected.

Clem