Yesterday we had a lot of jobs and sessions hang on a 969/220 running
MPE/iX 5.5.  This went on for several hours, and then suddenly everything
was OK again.  We are trying to determine the cause.

Everything that was hung was in one production account.  The majority of
the sessions and jobs were in other accounts, many of them running the
same programs from a common account, and they were not affected.
DBUTIL did not show any database locks in the account.
One theory is that something was holding a lock on a flat file which is used
by almost everything that runs in the affected account.  If  true, it would
explain why everything suddenly started to run again, when the lock was
finally released.

The System Manager used Lund's SOS to look for problems:

"SOS in addition to impedance also indicated that the current wait state
was a CONTROL BLOCK WAIT.) I'm trying to determine exactly what the CONTROL
BLOCK WAIT is indicating "

Can anyone tell me what CONTROL BLOCK WAIT means?

Cecile Chi