A cautionary tale:

Enter
LIMIT 1,1
or an appropriate number on the console, where the first number is the
maximum number of jobs, the second is the maximum number of sessions. In
one shop, we gave the operator both the console and an extra terminal,
which tended to stay logged on, and no users could stream jobs, so
allowing a job that was not yet streamed was not a problem. Of course,
this does not affect existing session; if three sessions are signed on,
they stay signed on, but no new ones can be initiated.

One morning, I could see that the spoolfile, job and session numbers
were rather low. Turns out that an operator had entered LIMIT 1,0 while
preparing for backup. The next shift operator arrived more than just a
few minutes early, and, as we expect them to, went to the console to
logon with his session name on the system console. Now, the operator had
already told the system to allow only one job, and no sessions, so this
new console session was disallowed. Never having been told about HIPRI,
one of them decided to restart the 3000, and in the excitement forgot to
properly take down everything that was running, with undesirable
results.

One of the aids I used to learn MPE was HELP. Entered by itself, it
displays the HELPMENU screen. Among the choice is HELPSTUDY; while this
starts off rather slow, explaining for instance what a computer is, it
does get better. Eventually, you should get to useful information.
Getting sent to training is probably a good idea; also, aren't those
classes available on video tape?

Welcome to the 3000. I listen in wonder to what administrators of other
kinds of systems have to worry about, and am so very grateful to have so
fewer worries.