Taking a system dump without a crash

[William M. Kules]

This is an oddball question that has been kicking around my brain for a
while.

When I worked on mainframe unix (System V), there was a way to take a
"snapdump" of a running system, i.e. like the image you get if you do a
savecore(8) after a crash.  Essentially the system was stopped, an image
of main memory was copied to disk, and the system was continued.  The
image could then be examined at leisure, and the users wouldn't be too
inconvenienced.

It's obviously easier to justify this capability on a mainframe than on a
Sun, since there are more people being inconvenienced when you have to
re-IPL a mainframe than when rebooting a Sun.  But -- it's still hard to
convince those 20 Sun users that you have to bring down their machine, and
wouldn't it be nice...

Has anyone tried to do such a thing under SunOS?  A 'g0' from the boot
PROM is usually an effective way to get a dump, but it doesn't return.
>From reading the PROM User's Manual, it looks like the 'g' command can be
used to jump to other routines.  Does anyone know of one that copies core
to disk (or does something else interesting)?

Please reply to me directly.  I will summarize if I actually find out
anything.

Many thanks,

Bill Kules, Automation and Research Computing |	Internet: wmk at fed.FRB.GOV
Federal Reserve Board, Washington, DC	      |	    UUCP: uunet!fed!wmk
"Recycling:  Just do it, dammit!"             |	   Phone: (202) 452-3933