How were 32-bit minis built in the 70s/80?

[Jon Elson]

On 05/11/2019 06:14 PM, Warren Toomey via cctalk wrote:
> I'm building my own 8-bit CPU from TTL chips, and this caused me to think:
> how were 32-bit minis built in the late 70s and early 80s? In particular,
> how was the ALU built? I know about the 74181 4-bit ALU, and I know (from
> reading A Soul of a New Machine) that PALs were also used.
>
> Did companies get custom chips fabricated, or was it all off-the-shelf chips
> with a few PALs sprinkled in?
>
>
There were also the AMD2901, 2903, 29203 family of bit-slice 
components, with the 2910 sequencer.  I built a 32-bit basic 
microengine in about 1982, but the software development 
effort eventually led me to stop work on it.  I was planning 
to implement the IBM 360 instruction set, with extensions, 
as it was very easy to implement with microcode.

See http://pico-systems.com/stories/1982.html  for some 
description and photos.

Apollo built some machines which I think were programmed at 
the microinstruction level, without microcode, using 2903's, 
I think.

The VAX 11/780 used 74S181 ALU chips, I think.  There were 
not all that many 32-bit minis.
I can think of Interdata 7/32 and 8/32 models that were 
32-bit.  SEL also made a 32-bit mini.
The VAX 11/780 was completely done with off-the-shelf ICs.  
Later VAXes went to semi-custom ICs, and the MicroVAX line 
used full-custom ICs.  I suspect many other makers were so 
small, they could only use off the shelf parts.

Jon