See UCBSID in SYS1.MODGEN(IOSDUCBP) However, you should not need to be concerned with this when you issue the STARTIO macro. You pass an IOSB to STARTIO, in which you have set IOSUCB to the address of the UCB of interest. IOS will use the current UCBSID when starting the I/O operation. The UCB address is not changed by HYPERSWAP. Some of the contents of the UCB (including UCBSID) is changed by HYPERSWAP.
Jim Mulder z/OS Diagnosis, Design, Development, Test IBM Corp. Poughkeepsie NY > From: "John Sullivan" <[email protected]> > To: [email protected] > Date: 10/18/2018 04:50 PM > Subject: Alternate Channel Set information and Startio considerations > Sent by: "IBM Mainframe Discussion List" <[email protected]> > > I am doing Alternate Channel Set research and cannot find much that > references it, and nothing in the IBM docs about programming considerations. > Not much here on IBM-MAIN in the archives, either. > > I can't seem to find a field in the UCB that alludes to being the > current (sub-)channel set for a device. > There is an IOS service to get the Channel Set, but it returns the > value at IPL/NIP time. > Unfortunately, after a HYPERSWAP, that will be - wrong. > > Obviously, MVS can find it for console commands and displays, etc. > so it must be somewhere. > > Anyone out there that could share some expertise, please? > > Also, I have code that builds its own channel programs and issues STARTIO. > It is unclear what changes need to be made to detect that a > HYPERSWAP has occurred, that the device is now on another Channel > Set, and how to successfully access the device under this circumstance. > > Insights or contacts welcome. > Thank you. > John Sullivan ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
