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

Dave Wade dave.g4ugm at
Sun May 12 02:16:11 CDT 2019

> -----Original Message-----
> From: cctalk <cctalk-bounces at> On Behalf Of Steve Malikoff
> via cctalk
> Sent: 12 May 2019 01:50
> To: General Discussion: On-Topic and Off-Topic Posts
> <cctalk at>
> Subject: Re: How were 32-bit minis built in the 70s/80?
> Warren said
> > 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?
> >
> > Thanks, Warren

Also in the UK GEC used AMD2900 IC's for some of the GEC4000 series. Some details here:-

we used them in NERC (Natural Environment Research Council, as both X.25 packet switches and as general purpose computers in which role they were universally hated as the Fortran compiler was ANSI compliant in the draconian sense of the word and the scientists were used to DIGITAL Fortran which had many extensions.

Some history of the JANET network here:-


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