Some tips that may explain the behaviour that you are seeing: 1. IMS loads RENT programs in the region control task and REUS programs in the program control task (the significance is that under some conditions the program control task is re-attached by the region control task, whereas the region control task exists for the life of the MPP region). Any preloaded modules are gone if their owning task ends. 2. z/OS will purge the JOBPACK area for any job under some conditions -- this is outside of IMS control. An example of a condition that causes JOBPACK to be purged is some types of GETMAIN failure. This would cause apparently random re)LOAD of your preloaded application modules at unpredictable times There are more conditions and I no longer work with IMS much but this should give you some ideas to pursue. Fwiw, IMS documents requiring COBOL programs to be RENT if preloaded (only requires REUS for assembler). LE does do some unexpected things at edge conditions so that is a tangible risk for "unpredictable results". .
On Wed, Jun 5, 2019 at 11:48 PM Thomas Spina <[email protected]> wrote: > 2 part question on IMS PreLoad > > 1. IMS PreLoad in MPP regions - COBOL 6.1 RENT REUS modules. How is > HEAP/STACK storage handled? > > When is the HEAP/STACK storage for the PreLoad modules allocated and > released? > Module LOADed under MPP startup TCB > A. Storage allocated on LOAD. > Program does not get control or initialize > Storage initialized on 1 execution > Storage not released until MPP terminated > or > B. Storage allocated on 1st application program CALL > Storage released at end of task (end of TCB = end of transaction > thread) > or > ?. > > I believe scenario A. holds true; would like confirmation. > > Brings up question 2. > > 2. IMS PreLoad in MPP region - Assembler program, REUS, not > reentrant/NORENT. > IMS message: > +DFS667I . NON-REENTRENT MODULES HAVE BEEN PRELOADED > > When does module get LOADed? Re-LOADed? > A. Module LOADed under MPP startup TCB > ? when get DELETEd, re-LOADed? > or > B. Module *not* LOADed under MPP startup TCB; > Module LOADed under transaction/application on CALL as if the > module was not in IMS PreLoad > > Seeing indications of both; LOADed on startup but gets reLOADed at times. > Cannot explain why or what should happen. > > Thank you for your help folks. > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
