<snip>
It was visible in JES but nothing could be done about it, it did neither 
accept cancel nor force.
 
Fault Analyzer showed that the last thing that happened in the address 
space was trying to load some z/OS routines for termination (if it was not 
memory termination then it must have been task termination) and failed to 
load those routines because of an out of storage condition.
</snip>

You might consider the possibility that JES2 or Fault Analyzer is in error 
if this is true. If force is not accepted then the address space no longer 
exists as far as the system is concerned.
What exactly do you mean by "accept...force"? It is true that if memory 
termination fails because of some system error an address space could land 
in limbo. But that would not have anything to do with insufficient memory 
in the address space. And if the master address space (where memterm runs) 
has insufficient storage then some authorized program has screwed things 
up and you'll likely need to re-IPL (and find/fix that program).

<snip>
If task termination, which is an operating system function, requires 
storage in an address space with no storage left, it should ensure that 
there is always enough room for task termination.
</snip>

Unfortunately in the general case this is provably impossible. Just as it 
is provably impossible in the general case to detect infinite looping.

I would guess that a huge percentage of customers have chosen a prudent 
approach with their user exits to prevent the vast majority of these 
cases, by limiting regions size somewhat, not allowing someone to allocate 
as user-region storage all available storage (whether below or above 16M 
or even above 2G).

Peter Relson
z/OS Core Technology Design


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