I did not mean to imply I thought there was any hardship, it's just a
curiosity. Virtually everything I write is non-modifying reentrant (and
therefore refreshable). But the system does load APF-authorized modules
marked RENT into key zero storage, making them at least more difficult
to modify. Again, I have no complaints.
sas
On 2/20/2016 8:34, Peter Relson wrote:
The system has not attempted to make RENT programs non-writeable. It has
only, in certain cases, attempted to make them non-writeable unless key 0.
I do not know about CICS' RENTPGM=PROTECT option, but I'd guess that it
does something similar, expanding which cases. But it could go further,
conceivably, as the REFRPROT option does.
It is fully possible to write reentrant programs that are self-modifying,
but it is rarely done (and even rarer done correctly).
Many would consider it not much of a hardship to prevent such a case.
Peter Relson
z/OS Core Technology Design
