On Wed, 9 Oct 1996 14:02:55 +0300 (EET DST) 
 Jukka Marin <jmarin@pyy.jmp.fi> wrote:

 > One P90 system with 16 MB RAM and three IDE and one SCSI disk (2940
 > controller) started panicing every night with "panic: ptdi %x" while
 > doing fsck on the SCSI disk.  This system is running a kernel from
 > Jan/Feb 1996.  It has worked very well until now - and, like always,
 > "nothing has been touched, it just started crashing".
 > 
 > Any ideas?
 > 
 > Running fsck -f by hand on that partition doesn't crash the system,
 > but when I did fsck -f -n for all disks, it crashed.
 > 
 > Thanks in advance!

"Yuck."  The only think I can guess is that, for some reason, mapping
all of those user buffers into kernel space is too much for the 
limited i386 kernel address space to cope with.  (fsck uses character
device, which maps the user buffer directly into kernel space via
vmapbuf()).

It does seem odd that it would just start happening all of the sudden.

You may want to increase NKPDE in sys/arch/i386/include/pmap.h ... The
default is 12 ... You may want to bump it up to 24 (but I certainly
wouldn't go any higher than that).

Hmm, that panic message certainly could be a bit more informative.

Jason R. Thorpe                                       thorpej@nas.nasa.gov
NASA Ames Research Center                               Home: 408.866.1912
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