DEC (Digital Equipment Corporation) produced PDP and VAX.

Khin Maung Zaw wrote :

It’s kind of sad that DEC failed to keep up with their lead beyond PDP.

I don’t know why Ken Olsen was pushed out, my limited understanding was that he was not high on Unix (he had been attributed to calling Unix a ‘snake oil’), for some reason his attempts to push VAX/VMS didn’t take off as he might have liked. I’ve read it somewhere that he didn’t get much support within DEC on the VAX/VMS endeavor.

At the time, there was a talented group of DEC engineers in Seattle area (across the lake from Seattle, matter of fact we here called East Side – Bellevue/Redmond). If I recall correctly, the first Microsoft Data Center at Canyon Park, several miles north of Redmond, was ran by DEC folks in the late 80s, early 90s.

A brilliant OS​ architect, Dave Cutler, part of a triumvirate led DEC’s Star project, a virtual 32-bit extension on PDP 11/70. Star and its cousin Starlet became precursor to VAX/VMS among others. The triumvirate were working at the DECWEST facilities in Bellevue, next to the city of Redmond.

Around late 1980s, some events – of which I’m no clue whatsoever, Canyon Park Data Center staff as well as many of the DECWEST team became part of Microsoft.

As the saying goes, “The Rest Is History”. Dave Cutler and his team led the development of Windows NT, New Technology” and beyond. Some folks attributed Billg who manged to extract most of the DEC VAX team into MSFT.

[A titbit on VAX and NT] Mark Russinovich, received his PhD from Carnegie Mellon in 1994, wrote series of articles in the Windows magazine, comparing the deep down internals of vms and NT. He even discovered the names of the internal variables have the identical names between them.

He co-founded a company called “Winternals”, developed a set of Windows tools which quickly became a Swiss knifes for every Windows engineers. Needless to say, Microsoft bought his company, the tools became part of Windows. Mark became Technical Fellow, and now he is the CTO of Azure.