> > Hello experts, > One question regarding to SYSIEFSD.Q4 resource: > What is it used? Where can I find information about it? > > If a job tried to allocate a tape drive, will iOS tries to communicate with tape drive first > before it can get share access of SYSIEFSD.Q4? Or allocation only related with > software control block manipualtion? >
Have you tried to search this on the internet? Have you looked in the PLANNING FOR GRS type manuals on IBMs website? A quick search turned up the following short answer < snip> Mon, 02 Oct 2006 10:54:27 -0700 This has been a problem of varying severity ever since OS/360 Release 10 back in 1967 or so. I think Q4 is/was the UCB resource - but SYSIEFSD Q4 and Q5 were locked during OS/360 allocation - the most egregious form being an AVR tape mount, which blocked all other initiator processing. (also from an IBM Apar OA12454 Nov 7 2006) The VARY OFFLINE command is changed to wait for 5 seconds for the SYSIEFSD.Q4 resource to be obtained. If it is not obtained within 5 seconds, the request for the resource is cancelled to allow stalled Allocations to proceed. New message MSGCNZ0010A is issued to indicate that the command is delayed. VARY will then request SYSIEFSD.Q4 again and repeat the wait/cancel/reobtain processing until the resource is finally obtained. The IEEVARYD offline service is also changed in the same way as the VARY OFFLINE command. However, for IEEVARYD callers that cannot tolerate a delayed return from the service, a new flag, VDEV_DO_NOT_WAIT_FOR_ENQ, can be set so that the IEEVARYD service returns to the caller if the SYSIEFSD.Q4 resource cannot be obtained within 5 seconds. In this case, register 15 will contain a new return code, RC0C, on return from the IEEVARYD service. The caller of the service can choose to retry the IEEVARYD request if appropriate. <end snip> Lizette ---------------------------------------------------------------------- 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
