The 3.11 merge window closes

Posted Jul 17, 2013 16:18 UTC (Wed) by drag (guest, #31333)
In reply to: The 3.11 merge window closes by timrichardson
Parent article: The 3.11 merge window closes

Coincidentally "Windows for Workgroups" was the first Windows operating system that Microsoft started using internally for development. Prior to that Windows and DOS systems were programmed using Microsoft's Unix variants.

I also expect that most people here already know this, but Microsoft's first operating systems were Unix variants, not DOS.

The 3.11 merge window closes

Posted Jul 17, 2013 19:14 UTC (Wed) by Cyberax (✭ supporter ✭, #52523) [Link]

Incorrect. UNIX has never been used much in MS (even during the Xenix era).

And by the time 3.11 was released, NT was almost done. And the NT group had been dogfooding their own builds for more than a year by then.

First Microsoft OS

Posted Jul 17, 2013 22:59 UTC (Wed) by man_ls (guest, #15091) [Link] (1 responses)

I also expect that most people here already know this, but Microsoft's first operating systems were Unix variants, not DOS.

I found a detailed article which does not agree: apparently the first Xenix release was late in 1982, while DOS was released in August 1981. It is true that Microsoft had been working on Xenix since before they started with DOS, though. So it depends on how you define "first operating systems".

First Microsoft OS

Posted Jul 18, 2013 13:33 UTC (Thu) by anselm (subscriber, #2796) [Link]

When Microsoft got started, the BASIC interpreter on many computers doubled up as the operating system since it was the (ROM-based) program that was booted when the computer was switched on and supported commands for operating-system-like tasks. Since Microsoft was behind most BASIC interpreters of late-70s/early-80s vintage computers, that would make those Microsoft's first »operating systems«.

{MS,PC}-DOS, when it was new, was basically a CP/M-80 knockoff for the 8088 CPU. It would probably have been reasonable at the time to do DOS development on CP/M, at least to the degree necessary to get a kernel running on the 8088 machine. It was possible to translate Z80 assembly language to 8088 assembly language automatically, so once you had a call-compatible CP/M-like kernel around you could probably get most of your other stuff across fairly quickly.