[Info-vax] Reading Gordon Bell's VAX strategy document

[Dave Froble]

On 9/24/2023 10:29 AM, Johnny Billquist wrote:
> On 2023-09-24 16:10, John Dallman wrote:
>> Gordon Bell, who was Vice-President of Engineering at DEC 1972-83 is
>> still alive and documenting much of his life on the web. There's DEC
>> stuff at https://gordonbell.azurewebsites.net/Digital/DECMuseum.htm
>>
>> Something particularly interesting is this document on DEC strategy as of
>> 1979:
>>
>> https://gordonbell.azurewebsites.net/Digital/VAX%20Strategy%20c1979.pdf
>>
>> At the time, DEC's other active product ranges were PDP-8, DEC-10/DEC-20
>> and PDP-11. They had decided in 1975 to create an architecture that built
>> upwards from the PDP-11, rather than building lower-cost DEC-10 machines.
>> The reasons for doing that were the large installed base of PDP-11s and
>> the convenience of 8-bit bytes for data communications, especially with
>> IBM mainframes.
>>
>> As of 1978/70 they had achieved this and were deciding what to do next.
>> The strategy expressed in this document is to continue to sell the other
>> ranges, but concentrate development efforts on the VAX family, and that's
>> what basically happened. Using a single architecture is seen as a
>> competitive advantage against IBM's proliferation of incompatible
>> architectures, which is pretty reasonable, since IBM saw the same problem.
>>
>>
>> Bell regards competition from "zero cost" microprocessors such as the
>> 8086 and 68000 as likely more significant than other minicomputer
>> companies, but fails to make a plan to deal with them. DEC was eventually
>> defeated by 80386 and later PCs and RISC workstations, and that failure
>> seems to start here. He assumes that DEC can dominate the market for
>> terminals for its minis by using PDP-11 and VAX microprocessors, but
>> doesn't seem to realise that compatible terminals can be built at much
>> lower cost using third-party microprocessors. In any case, the
>> replacement of minis by PCs and workstations meant that the terminal
>> market basically vanished.
>>
>> The idea of running VMS on a terminal with a total of 64KB of RAM and ROM
>> in 1982 seems implausible now, but it seems to have been the reason for
>> 512-byte pages. Bell praises the extremely compact VAX instruction set
>> and its elaborate function calls, without appreciating the ways they will
>> come to inhibit pipelining and out-of-order execution, and thus doom the
>> architecture to uncompetitive performance.
>
> It's always easy to see mistakes after the fact.
> When the VAX was designed, as well as around 1980, memory was still rather
> expensive. An instruction set that lead to smaller binaries was a big win at
> that point in time.
>
> What you could possibly argue was that DEC didn't enough see or anticipate the
> drop in price of memory, which would lead to totally different constraints and
> optimal points.
>
> VMS was never expected to run on something with 64K. You couldn't even run a
> reasonable PDP-11 on that little memory at that point. (I said responable, for
> anyone dragging out a minimal RT-11 system.)
>
> But VAX was most definitely designed for getting programs more memory efficient.
> More addressing modes, more things done in microcode to deal with things in a
> single instruction. Very variable length instructions... All was about memory
> cost. Which made a lot of sense between 1970 and 1985. After that, memory was
> becoming so cheap there was no reason for the optimization angle the VAX had
> taken. And you had the rise of RISC.
>
>   Johnny
>

Well, you're right about "after the fact" ...

I cannot remember exactly when the first C-VAX came out, but when it did, DEC 
then made the fatal mistake.  I'm not sure they actually had any options.  The 
company was rather "top heavy" with many employees to support.

If DEC had went after the low end market with the C-VAX, I really feel that DEC 
would still be with us today.  Since PC users don't have large budgets for 
support and such, DEC would have had to downsize the labor force, and that was 
something they would have a hard time with.

Doesn't matter, cause that was and is the direction the market was heading, even 
back then.  It could not be resisted.

But, figure a low cost VAX vs the PCs of the day.  With good marketing, and 
pricing, Intel would not have become what they are today.

It was going to happen anyway, DEC resisting, just killed the company.

-- 
David Froble                       Tel: 724-529-0450
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