Basic System Problem Analysis - August 2003

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Hangs
Hangs do tend to be more difficult to diagnose than aborts. Often what is called a “hang”
is really a performance slow-down. It can often be limited to a particular application or
area of the OS.
If the sole function of a system is to run account’s payable and the accounts payable yet
anyone trying to do so hangs then it is technically correct that the “system” is hung. But
telling that to a support engineer might mislead them badly!
If is important to determine the scope of the problem. Are only certain users affected?
Are certain programs or applications affected?
Is it possible to log on the system? And log off? Does a control-A produce an equal (=)
sign? If so than the OS is able to respond.
If people are unable to connect to the system how are they connecting, DTC, TELNET,
VT, FTP, via the web? Do some connection methods work where others don’t
If the problem is going to require a reboot to clear it then if you haven’t determined the
cause and can invest the time you should get a memory dump. Even if all you do is hold
on to it, it is better to have it than not have it if the problem appears again.
But remember, memory dumps of hangs can be a log larger than memory dumps of
system aborts. They will take longer, especially if you are writing them to tape.