On Tue, 1 Sep 2009 16:39:09 -0700, John Mattson wrote: >Looks like that is it Gil, Exclusive enque causes it. Chalk it up to >another misleading IBM message. > What has been needed (although IBM won't acknowledge it) ever since TSO's interactive computing appeared alongside the purely batch paradigm of OS/360 is a facility to downgrade an ENQ from EXC to SHR, so after the "Z" ISPF could restore the status quo ante.
This could be synthesized, crudely, with facilities available nowadays: o fork() a child process (runs in a different address space) authorized to issue ENQ SHR SYSDSN with wait. o Once the child issues the ENQ, it signals the parent which does DEQ (might require FREE). o Once the child obtains the ENQ, it signals the parent which does ENQ SHR (ALLOCATE as needed). o The parent then signals the child to terminate (or simply kills the child). -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
