[uncomputation]

You have it backwards on two counts. First count is the point of POSIX is any OS vendor doesn’t need to worry about any other OS compatibility. Just implement POSIX interfaces. Second count is that is OP’s exact point: it never has been done before, because too many OS vendors give POSIX very little thought. This helps realize the original vision of POSIX.

[CharlesW]

> First count is the point of POSIX is any OS vendor doesn’t need to worry about any other OS compatibility. Just implement POSIX interfaces.

I must be missing something. How are you getting from "just implement POSIX interfaces" to "compile once run everywhere"?

Wouldn't the former just promise that you could compile the same source on any POSIX-compliant OSs and get a binary that runs on that OS, on that architecture?

[gavindean90]

It's because cosmos implements POSIX in a portable way

[rhizome]

POSIX was never about binary portability.

[stephc_int13]

The binary portability is, in practice, not the most difficult feature, as long as the CPU arch is the same. It is also kind of a hack and IMO a nice-to-have feature but not as vital as true portability.

POSIX was not limited to the Unix world, the goal was for it to be implemented by all OS vendors, and it was partially done.

[sheepscreek]

Well said. In reality, it has been more about supporting common system level APIs (think read, write, fork, etc).