2.11BSD, non-split i/d issues
Steven M. Schultz
sms at moe.2bsd.com
Thu Feb 18 02:32:00 AEST 1999
> From: maximum entropy <entropy at zippy.bernstein.com>
> I would prefer to use 2.11BSD because I understand it's still actively
> used, and not as buggy as 2.9. But everything I've read about 2.11BSD
> says that it needs split i/d to run. Can anyone give me more detail
> about this? Was support for machines without split i/d removed from
> the kernel, or is it just that some of the programs are too big to fit
> in a single 64k segment?
Oh, support was NOT removed. Non-split executables (magic number
0407 and 0410) will still run.
The kernel will not fit - without split I/D it is impossible to
create a /unix image that fits within a single 64kb (actually 48kb
since the kernel stack takes 1 segment and the 'u' area takes
another) address space.
I actually went thru the exercise once (2.10 era) of creating a bare
bones kernel that would fit in - at least the linker said it would.
That was only done by ripping out lots of stuff - no networking, no
statistics gathering, almost no drivers, etc. Never 'ran' it though
since there seemed to be little point in such a stripped down system.
Even V7 was hard pressed to run on a non-split machine! In fact there
was a paper written about shoehorning V7 onto an 11/40 and the hoops
that needed to be jumped thru. Not sure but that document might be
in the /usr/doc tree of one of the PUPS Distributions hierarchy.
More information about the TUHS