Re: COMPAT_IBCS2 on Vax

[Johnny Billquist <bqt%update.uu.se@localhost>]

On 2017-08-03 10:24, Maxime Villard wrote:
> Le 02/08/2017 à 23:02, Kamil Rytarowski a écrit :
> > It started as SVR4 i386. IBCS2 ELF was renamed to compat_svr4, and
> > compat_ibcs2 was used for i386 SVR3.
> >
> > I think that the ibcs2 evaluated as an alias for SVR3. I don't know
> > whether somebody reused this name on original VAX UNIX.
> >
> > I proposed to keep it as it is, because there are more aliases like i386
> > that have not clear meaning.
>
> Alright, thanks for the archeological digging.
>
> I still I'm not sure what exactly this all means: if compat_ibcs2 is in
> fact
> compat_svr3, and if the real iBCS2 implementation is in fact
> compat_svr4, what
> is compat_svr4 doing on sparc/sparc64?
>
> Again, iBCS2 is a standard for x86; does this standard happen to be
> compatible
> with the sparc-like SVR4? Sorry if I'm being dumb, but this does not seem
> obvious to me at all.

Reading up on iBCS2, it seems like a misnomer to have that name for the 
kernel compatibility. If I understand iBCS2 right, it's both a ABI 
(which would then be SVR3?) and also specifications for file system 
layout and other details, which is not at all controlled by any kernel 
option. So, even with compat_ibcs2, we might not be compatible with iBCS2.

Like I said before. SVR3 and SVR4 makes more sense to me. iBCS(2) is 
other stuff that don't make sense around here, in my opinion.

	Johnny

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