The Bellmac-32 was pretty amazing for its time - yet I note that the article fails to mention the immense debt that it owes to the VAX-11/780 architecture, which preceded it by three years.

The VAX was a 32-bit CPU with a two stage pipeline which introduced modern demand paged virtual memory. It was also the dominant platform for C and Unix by the time the Bellmac-32 was released.

The Bellmac-32 was a 32-bit CPU with a two stage pipeline and demand paged virtual memory very like the VAX's, which ran C and Unix. It's no mystery where it was getting a lot of its inspiration. I think the article makes it sound like these features were more original than they were.

Where the Bellmac-32 was impressive is in their success in implementing the latest features in CMOS, when the VAX was languishing in the supermini world of discrete logic. Ultimately the Bellmax-32 was a step in the right direction, and the VAX line ended up adopting LSI too slowly and became obsolete.

You might want to be more specific by what you mean by "modern", because there were certainly machines with demand-paged virtual memory before the VAX. It was introduced on the Manchester Atlas in 1962; manufacturers that shipped the feature included IBM (on the 360/67 and all but the earliest machines in the 370 line), Honeywell (6180), and, well... DEC (later PDP-10 models, preceding the VAX).

The article says the Bellmac-32 was single-cycle CISC. The VAX was very CISC and very definitely not single cycle.

It would have been good to know more about why the chip failed. There's a mention of NCR, who had their own NCR/32 chips, which leaned more to emulations of the System/370. So perhaps it was orders from management and not so much a technical failure.

> introduced modern demand paged virtual memory

Didn't Multics, Project Genie, and TENEX have demand paging long before the VAX?

There was also the Nord-5, which beat the VAX by another couple of years as a 32-bit minicomputer.