Path: utzoo!attcan!uunet!auspex!guy
From: guy@auspex.UUCP (Guy Harris)
Newsgroups: comp.sys.next
Subject: Re: The NeXT machine has been announced! (was long)
Message-ID: <21@auspex.UUCP>
Date: 19 Oct 88 16:14:06 GMT
References: <360@elan.UUCP> <2070@cloud9.UUCP> <6483@pasteur.Berkeley.EDU> <530@sactoh0.UUCP> <24926@tut.cis.ohio-state.edu>
Reply-To: guy@auspex.UUCP (Guy Harris)
Organization: Auspex Systems, Santa Clara
Lines: 30

>No, Mach is just 4.3BSD, with no SysVisms thrown in (that I know of).

"Just 4.3BSD"?  I wouldn't go that far at all.  The kernel has a heck of
a lot of non-4.3BSD code in it (and I think they want to move a lot of
"kernel" code *out* of the kernel entirely).

> A Mach machine is one of the purest 4.3 systems you can find any more
> from a commercial UNIX producer, since they're all mixing in varying
> amounts of SysV in various ways.

Which isn't necessarily a good thing; "the varying amounts of SysV"
aren't just thrown in because S5 compatibility is a checklist item, much
of it is thrown in because it's good stuff (HDB UUCP, the S5 Bourne
shell, the S5 "make", the S5 "old awk" which is faster than the earlier
version that comes with 4.3BSD, the S5R3.1 "new awk", etc.).

>In fact, FSF says that the Mach group is working hard on removing any
>residual code that's still subject to the SysV license,

Which includes a lot of 4.3BSD kernel code (which is presumably one
reason they're starting with Mach).

You could call Mach a "4.3BSD look-alike", except that 1) "look-alike"
seems often to be somewhat pejorative, implying that it may not be the
Real Thing and may not work like the original, and 2) a lot of the code
comes from 4.3BSD (I suspect they didn't bother rewriting all of the C
library or the utilities, although they may have changed some of the C
library to make it work better with multiple threads in a single address
space - I think they did change standard I/O so that it could use file
mapping).