On 2019-Aug-08 07:33:47 +1000, Dave Horsfall <dave@horsfall.org> wrote:
>I've always thought that Xenix was insane to start with...  Then again, my 
>first experience with it was on a 286...  Now, when porting Unify, should 
>I use large memory model here or small memory model?  Crazy.

Ah, yes.  I remember it well.  The large, small and various mixed modes
were a consequence of the braindeadedness of the 286 - reloading segment
registers (pretty much every memory reference in large mode) was abysmally
slow.  I recall hacking mg (a cut-down emacs clone) so that buffers were
in "far" memory and everything else was "near".

Some of the Xenix features I recall were:
* occasionally fork() would return -1 in both the parent and child (or
  something like that - it would both succeed and report failure)
* The contents of comments would affect the Pascal compiler's ability
  to compile the program (this was "using uninitialised variables"
  behaviour, rather than magic lint-style comments).  It made software
  development "interesting" because checking a program into SCCS might
  stop it compiling.
* fork()ing a large process could panic the system.
* The C compiler barfed on parts of starchart (from comp.sources.???)

-- 
Peter Jeremy