Autzoo.1225
hacknews
utzoo!henry
Thu Dec 17 19:02:01 1981
magtape broken
Backups today did not go well.  The magtape refuses to do anything.
A process that tries to use it hangs, with no tape motion.  When I
tried it single-user with a background process, just that process
hung.  When I tried it multi-user, the whole system hung until I put
the drive offline in an attempt to wake things up.

Powering down the system does not help.  Powering down the magtape
drive does not help (I thought of this rather late, which is why I
tried using the magtape multi-user after we came back up).  Pulling
out the sixth DZ does not help (I didn't bother putting it back in)
(and yes, I did remember the grant continuity card and it's in the
right way).  The magtape cables do not appear to be damaged and all
the plugs are in securely (I pulled one of the controller boards
partway out to check).  The magtape thinks it has been selected
successfully, and the incident with the system hanging until the
drive went offline shows that the controller IS aware of the drive's
existence.  The controller registers look like the "bus grant late"
error bit may be stuck on, although the overall "error" bit is off.

Backups are cancelled until this is fixed.  Repairing this is, I
think, important enough to justify any downtime involved, hence the
message-of-the-day.