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Comment by rbanffy | Hacker News Reader

I remember NT was to have an OS/2 subsystem, probably because it started out as OS/2 3.0, with a New Technology (NT) kernel. I know there was a POSIX system, but I never saw or interacted with it and, legend says, it was only used to check a box in government contracts.

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The original POSIX subsystem was not very useful -- a minimal set of system calls, plus a Microsoft re-branded MKS Toolkit to provide shells and utilities.

Microsoft ended up buying Interix, who offered a much more pleasant UNIX-on-Windows setup. That was supported for many years as "SFU" and later "SUA"

SUA was still a pretty weird UNIX though. PE-COFF binaries, and a linker that wasn't 100% GNU compatible, and a lot of other little oddities. Porting software to SUA was never very much fun.

I assume that was the motive for WSL -- same idea as SUA, but less weird for software ports.

On XP and 7 (and 8, perhaps) I used Cygwin to have a Unix-like environment. Does it still work on Windows 10? I remember I could call Windows programs from it and manipulate Windows files.

Cygwin is a very different approach.

SFU/SUA lived in kernel space -- they implemented a new set of system calls alongside win32. Binaries for SFU/SUA could not be executed on a system without SFU/SUA configured, because the kernel subsystem would be absent. (I also don't believe you could call win32 from SUA, but my memory is foggy.)

Cygwin and MSYS are attempts to map UNIX semantics onto windows system calls, to varying degrees of success.

True, but it has some of the features the author mentions he would like from WSL1 (such as the bi-directional visibility), and, being open-source, if they really want it, they can always add it.

Cygwin is definitely still around, but most people are using msys2/mingw and its bash prompt nowadays, especially with Git for Windows making it nearly ubiquitous.

I believe it does, but you might like MSYS2 more.

> wasn't 100% GNU compatible

But, but... GNU's Not UNIX!

I remember using Interix back in the late 90s to port our home-grown source control system that we used on various UNIX flavours over to NT. The source control system was basically a bunch of shell scripts which wrapped either SCCS or RCS depending on which was available on the system in question. Porting them to Interix on NT worked pretty well, though there were some wrinkles with file permissions.

My understanding is they initially developed the tech beneath WSL to run Android apps on Windows Phone, actually.

https://mspoweruser.com/windows-subsystem-for-linux-started-...

> SUA was still a pretty weird UNIX though. PE-COFF binaries

PE-COFF comes from UNIX originally – COFF was the executable format introduced by AT&T in Unix System V, up to and including SVR3 – in SVR4, it was replaced with ELF. PE-COFF is simply Microsoft's variant of COFF. There are other variants, such as IBM's XCOFF (used on AIX). Given that COFF originated on UNIX and has a long history of use there, should we really call a UNIX(-like) "weird" for using it?

The UNIX standard doesn't mandate any particular executable file format. macOS uses Mach-O. z/OS uses GOFF. Both are certified UNIX. (Interix/SFU/SUA never was, but there was nothing stopping Microsoft pursuing UNIX certification for it if that had been a priority for them.)

SVR4 was released in 1990, before win32 or NT even existed. By the time Interix came along, the whole world was ELF — there was even an Intel standard that unified all x86 UNIX ABIs, iBCS.

AIX is the only Unix to retain COFF.

It’s deeply weird, unsupported by standard tools, and shipped with a not quite 100% compatible shim for the gnu linker.

Trust me when I say it is not a fun combination.

Gentoo-prefix on SUA was my daily driver for years. I had all the “could you imagine” stuff mentioned in the article - dealing with the random build errors now an then did get old though. I always wondered why more people didn’t use it especially seeing how popular WSL is now. Maybe SUA was just ahead of its time?

There were so many of these - the original POSIX subsystem, MKS, Interix, a bunch I'm surely forgetting, Cygwin, etc.

None of them quite lived up to the design promise of a frictionless 'personality' OS layer on top of the existing OS. If anything, I'm curious how Microsoft, organizationally and technically, decided to give this yet another go with WSL1 - perhaps 'fail fast' and switching to virtualization was something they'd considered as a plausible escape hatch from the start.

Wikipedia has a medium-sized article for the SFU: https://en.wikipedia.org/wiki/Windows_Services_for_UNIX

The OS/2 subsystem existed and shipped up to Windows 2000.

Really?! I tried to run a couple OS/2 binaries back then without success.

Did you have to do anything special?

You had to enable the feature and it only supported OS/2 1.x apps (console). No GUI support.

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