[TUHS] First Unix-like OSes not derived from AT&T code?

[Miod Vallat]

> The RT 4.3 port was called AOS (for the, "Academic Operating System"). It
> was mostly Tahoe with NFS and came with most of the sources, but some bits
> were distributed only as object code: I believe some of the MM bits?
> Perhaps the MMU code? I vaguely recall this being one of the things people
> had a hard time with when trying to port Reno and 4.4 to the RT.

What was delivered as binary was the Advanced Floating-Point Accelerator
microcode.

At the end of the AOS work circa 1996, most of the kernel was 4.4,
except for the network stack which was 4.3-Reno, and the VM system which
was still 4.3 (hence no mmap).

> The port was fairly faithful; the C compiler was a bit strange "High C" or
> "Hi C", bit GCC was available after a while, but had some bug and could not
> compile the kernel.

The compiler was Metaware High C. GCC could not be used to compile the
kernel sources unchanged, because one of the locore->trap.c paths was
relying upon the stack layout used by the compiler. With that fixed, gcc
could be used to build a working kernel.

Miod