the /debug partition

[Bernard Kirby]

We recently had one of our machines upgraded to a 4D-70GT running
version 3 of the operating system (4sight 1.0 etc). After all the
software was installed we noticed that a  "df" showed an "extra"
partition /dev/debug of type dbg mounted on /debug. It was about
50Mb in size! There appeared to be files in the /debug directory,
but whenever you tried to look at them, nothing happened, like they
were zero length files, except that "ls -l" showed that some of them
were quite large in size. The number and size of files varied as the
machine was used. This partition was not in /etc/fstab but was in 
/etc/mtab. So, one day in a fit of experimentality we simply "umount"ed
it, and it hasn't reappeared since, even after a reboot. 
Now for the questions.

a) Is this a "hidden" partition that is secretly present on all SGI
   machine's disks, only manifesting itself when explicitly mounted?

b) Is it really about 50Mb in size, or is that simply a function of "df"
   misinterpreting a file system of type dbg.

	OR

c) Did the Version 3 system repartition our disk without telling us?
   If it did, then it must have zapped some files. 

d) Can we use it for something else, like an NFS partition?

e) If we can't use it for anything else, can we reclaim the disk space?
   (If in fact is really is using disk space)

f) What the F**k's it for? Why did it just show up unannounced, with no
   documentation about what it's doing.

Thanks, 
	Bernie Kirby.