The issue is that if you don't have the local lock anyone else in the address space can issue a virtual storage request that will change the SPQE-DQE-FBQE chains while you are running them, and the next pointer may no longer be valid. As long as you are just looking, you will get an S0C4 in the SRB. Trying to get into another address space to "poke" around requires a lot of nerve, not to mention a VERRY good understanding of z/OS Recovery and a good understanding of IPCS to try and find the knots you've tied yourself into. Granted, this is how many monitors work, but they utilize layers of recovery to cover their tracks. However, even though in this case holding the local lock for the target address space will keep you from having the VSM control blocks modified, there are a ton of other considerations to be dealt with in locked code.
Wayne Driscoll Product Developer NOTE: All opinions are strictly my own. -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Lindy Mayfield Sent: Tuesday, August 19, 2008 11:55 AM To: [email protected] Subject: Re: A couple of memory/storage questions I have no problem running authorized. I have a z10 in my basement. So you mean that if I read a control block that points to another one, etc, and this points to memory, then I need to basically stop the address space from doing anything until I'm all done reading. Is that about right? -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Wayne Driscoll Sent: 19. elokuuta 2008 19:37 To: [email protected] Subject: Re: A couple of memory/storage questions Lindy, Scheduling an SRB requires update access to an APF authorized dataset, since SCHEDULE requires SUP state and KEY 0 while IEAMSCHD requires KEY 0 or SUP state. In addition, there are serialization concerns, because unless you hold the local lock, you can't guarantee that all these control blocks will remain static. Actions like this done incorrectly can cause painful consequences. If you have a sandbox LPAR (or better yet, a sandbox z/VM guest) you might be able to dig through it, but be prepared to know the IPL procedure. Wayne Driscoll Product Developer NOTE: All opinions are strictly my own. ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- 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
