On Tue, 16 Jan 1996 13:36:00 EST Rudderow, Evan said:
 
I'll snip the original and take a guess...
 
VSCLOSEing and VSOPENing user volumes involves the AVR process.  AVR is a
strange beast, and single-threaded.  If AVR is hung on a device, then you
are just hung.  To test that theory, mount a DAT in a drive and put it
online to see if the system does AVR on the tape.  I suspect AVR got hunt on
one of your "disabled/disoriented" discs.
 
We used to have two 7980 tape drives on an old HP-IB switch (yes, I know
that isn't supported either).  The idea was to switch the two drives between
two systems so we could use parallel store sets.  It worked most of the time
but if you hit the switch at the wrong time, AVR would hang up.  Consequently
you could hang up VSOPEN/VSCLOSE of user volumes too.  The "suggested method"
was to set the switch to the target system, load a tape on both drives, then
do the VSOPEN/VSCLOSE.  This usually kept AVR happy.
 
Jeff Kell <[log in to unmask]>