Xenix Shared Data Bugs (and friends)

[Robin Cutshaw]

As usual, this posting relates to IBM Xenix 1.0 for the PC/AT...

There is a problem with the shared data code with Xenix.  It seems that a
program compiled with the large model cannot write into shared data space
of programs compiled with the small or medium models.  Large may talk to
large but that's it.  There is no problem with small and medium models
talking to each other and they can write into large model space but just
not vica-versa.  (IBM is working on it).

On the previous posting reguarding the "Panic Kernel (easy to do)", IBM has
really shown their colors.  The jist of the article was that if you call
getcwd() between sdenter() and sdleave() you will get a kernel panic (if you
have stdio.h included and a few other things).  IBM's official response to
this is "SEE PAGE 2-194 of the Software Command Reference where it says 'system
calls should be avoided between sdenter and sdleave calls'".  This is their
only response!  So now everyone who doesn't read and follow the directions on
page 2-194 will be able to easily panic and crash the Xenix kernel.

UNBEWEVIBLE!

If you look at the reference page for nlist() you will see a reference to
xlist().  This is the equivalent for x.out type with a little different
format.  You will find no reference page to xlist() and IBM says that their
will be none and in fact the reference on nlist to xlist will be removed.
Even so, if you look at /usr/include/a.out.h you will see the format for xlist()
use and it works well.

Reguarding CPP, the command reference notes that this is called as the first
pass of cc.  This is not the case.  CPP is almost unusable due to the fact that
it is not compatible with the c pre-processor used by cc (for example, their
is no way to specify identifier names larger than 8 chars).

'till I crash again...	-robin

-- 
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Robin Cutshaw
uucp:   ...!{akgua,gatech}!medstar!robin