IBM Mainframe Discussion List <[email protected]> wrote on 04/26/2007 07:39:42 PM:
> On Mon, 23 Apr 2007 20:37:29 +1000, Shane <[EMAIL PROTECTED]> wrote: > > >On Mon, 2007-04-23 at 04:15 -0500, R.S. wrote: > > > >> The message regards tape device. > >> How to find out what system holds the device ? > >> (except from checking it on every system console) > > > >And to (partially) answer the question ... > >When we have seen this, we weren't able to ascertain the holding system > >(from the victim). *Very* disconcerting when it's a system outside of > >the 'plex - that isn't even supposed to be activated. > >Especially when the 'plex has tape sharing and the rogue system doesn't. > >Scott will have the definitive answer - should he be disposed to stir. > > > >Shane ... > > No good answers, just some background information. When an ASSIGN fails, > the function that attempted the ASSIGN (either device allocation or, as in > this case, VARY ONLINE) _could_ issue a follow-up command to the device to > determine "who" has it assigned. As you can surmise, these functions > currently don't do that. > > There is a difference in processing for VARY ONLINE for a tape device, > depending on the autoswitch status of the device. If the device is > autoswitchable, then the ASSIGN is not needed to bring the device online, so > I believe it is bypassed. For autoswitchable devices, the ASSIGN is > obtained when the device is allocated. > > If the device is dedicated (not autoswitchable), then the ASSIGN is obtained > and held for the entire time the device remains ONLINE. > > It would seem to be a reasonable requirement to have the system do some > interrogation of the device when the ASSIGN is 'unexpectedly held'. > For DASD control units, IOS issues a Reset Allegiance command, which returns the dynamic pathing Path Group ID of the path group holding the reserve, which contains the CPU Serial Number and LPAR ID. I don't know if there is currently any similar capability in tape control unit architecture to obtain the Path Group ID of the path group which owns the ASSIGN. Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY ---------------------------------------------------------------------- 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
