[TUHS] Re: Patches to improve 6th Edition

Wolfgang Helbig helbig at Informatik.BA-Stuttgart.DE
Sun Dec 29 06:38:31 AEST 2002

some hours ago I wrote:
>I ask this, because my system crashes ones in a while. But I changed it
>here and there, so it might be my fault.

It *was* my fault! So far, I have only found one bug in V6: The size
of swapmap and coremap are configured too small, so they might overflow.

The sizes don't take account of shared text segments, that produce
extra chunks of free memory. In V6 there are 19 pure executables, so their
minimal size should be (NPROC+19)*2, or better yet (NPROC+NTEXT)*2, where
NTEXT should be set to 20 instead of 40 as distributed in param.h .

I don't think this bug ever showed up. It is very unlikely. In V7 these
sizes are choosen to be even smaller than NPROC and even with its many pure 
executables, I don't think V7 ever crashed because of this bug.

So, with the only exception reported by Brian S. Walden, there seem to be
no bugs in V6 that crash systems.



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