The Validated Boot enhancements to z/OS made a change to a channel program that we use to build the nucleus. The changed channel program is used regardless of whether you are doing a validated boot or not. z/VM minidisk caching screws up while emulating the channel program. Last I talked to the z/VM developers, they still had not figured out what the bug is. As long as minidisk caching (MDC) is turned off for at least the z/OS IPL device minidisk, the channel program will be executed by the I/O subsystem, which executes it correctly. The problem only occurs when you are IPLing z/OS from a minidisk to which you have LINKed (or is in your VM directory), with MDC enabled for that minidisk. If you instead ATTACH the device to the VM user, the problem will also not occur, since it is not being treated as a minidisk in that case. The type of processor or DASD controller is not relevant to the problem.
Jim Mulder -----Original Message----- From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Keith Gooding Sent: Tuesday, October 24, 2023 1:37 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Heads up: z/os 3.1 WAIT 006 under z/VM + DS6800 question It was z/VM 7.2 (still in support) but the APAR states that the problem affects all z/VM releases. > On 24 Oct 2023, at 18:33, Art Zeigler <azeig...@sdsusa.com> wrote: > > What relase of z/VM did you receive the Wait 006? > > Thanks > > Art Zeigler > > ________________________________ > From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on > behalf of Keith Gooding > <0000034af3894af4-dmarc-requ...@listserv.ua.edu> > Sent: Tuesday, October 24, 2023 1:27 PM > To: IBM-MAIN@LISTSERV.UA.EDU <IBM-MAIN@LISTSERV.UA.EDU> > Subject: Heads up: z/os 3.1 WAIT 006 under z/VM + DS6800 question > > For my first z/OS 3.1 IPL (under z/VM) I got WAIT 006. After a long search I > found z/VM APAR VM66721: Z/OS GUEST IPLS FAIL AFTER APPLYING UJ92591/UJ92728. > There is no PTF as yet but there is a work-around (turn off mini-disk > caching). > > Those PTFa are the validated boot PTFs for z/OS 2.5 - the function is > incorporated into z/os 3.1. > > I have no idea why the failure occurs but I thought maybe z/os is using some > I/o command sequence which z/Vm does not support properly. That got me > worrying about whether z/OS 3.1 (or 2.5 with the validated boot PTFs) will > work on old hardware, specifically DS6800 which we have at a backup site. Our > 3.1 test under z/Vm used DS8884. > > Has anyone tried running 3.1 (or 2.5 with the validated boot PTFs), or have > any understanding of why an IPL may fail on DS6800 ?. We are not using > validated boot and have no intention of doing so. > > Keith > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send > email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, send > email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
