[netbsdusers]

Windows has extreme similarities with Unix, and if you would look at a really different OS like, for instance, IBM i, it becomes clear. The Windows-Unix affinity is so great that you even interact with devices through file handles by Read, Write, and IoCtl methods.

Check "Inside Windows NT" by Helen Custer, an official account. She explicitly credits the handles to Unix. That's not surprising - not only was Unix fresh on the minds of the NT developers, with quite a few of them having Unix backgrounds, but every conceptual ancestor of Windows NT was at least significantly influenced by Unix:

- VMS: The VAX/VMS team were in regular contact with Ken Thompson, and got the idea for channel IDs (= file descriptors) for representing open files and devices from him, as well as the idea of three standard channels which child processes inherit by default: input, output, error (the error one was at the time a very recent development, I think in Unix v6 or v7)

- MICA: Would have been a combined Unix and VMS compatible system.

- OS/2: FDs with read, write, ioctl again.

Even MS-DOS is already highly Unix-influenced: they brought in file descriptors in DOS 2.0 and even called the source files implementing the API "XENIX.ASM" and "XENIX2.ASM" (see the recent open source release.)

I have deliberately chosen to not make anything of the fact that Windows NT was intended to be POSIX compatible either (and even supports fork, which WASI mercifully doesn't) because my point is the fact that all modern general-purpose operating systems are at least very much inspired and deeply indebted to Unix. I would accept that OSes that are not general purpose may not be, and old operating systems made in siloed environments like IBM are fundamentally very different. IBM i is very different to Unix and that's clear in its native APIs even though

Cocoa and Android APIs don't look much like the basic Unix APIs, it's true, even if they are implemented in terms of them. WASI wants to define APIs at that lower level of abstraction. It's tackling the problem at a different level (the inter-process level) to what object capability _languages_ are tackling (the intra-process level).

[mike_hearn]

Right, if you compare against IBM i then everything looks the same :)

NT might have been intended to have a POSIX personality in the very beginnings of the project, but that never happened. People who have tried to make this work over the years have always retreated licking their wounds, including Microsoft themselves. WSL1 tried to use this and failed because NT is too different to UNIX to implement a Linux personality on top, so WSL2 is just a regular VM.