In a message dated 11/21/2007 9:23:22 A.M. Central Standard Time, [EMAIL PROTECTED] writes: >Nucleus is not going to page fault. And if STARTIO fails before it gets the UCB lock, no harm - no foul - since nothing is "in the middle". So there are zero defects now in the nucleus? I doubt it. A disabled page fault is easy to handle - just ABEND the current piece of work and move right along. What happens next depends on what the current piece of work was. Even if the nucleus refuses to page fault, nevertheless disabled nucleus code can be interrupted and, if the interrupt status is not preserved, the nucleus resumes execution with interrupts now enabled, and I posit that the results of this situation would likely be far worse than if the nucleus suffered a disabled page-fault. Of course the nucleus is designed not to page-fault while disabled. One way that is guaranteed is by being sure that every byte ever touched by disabled code is fixed before doing the disabling operation. Which is what I have done in all the code I have written that explicitly disables via STNSM. And I have learned that if I want to do a GETMAIN for a system subpool while disabled and without holding a system lock, that I need to turn on a super bit to tell GETMAIN that the CPU is "officially" disabled. And when I get a disabled page fault ABEND dump, I know what to do to fix my bug. STARTIO, I'm sure, has an FRR that knows what to do if it fails after it gets the UCB lock and something is "in the middle". I still do not understand the necessity for the warning about MVS-guaranteed disablement's requiring a system lock's being held. One result of acquiring a system lock is the turning on of a super bit. But you can also turn it on with an OI instruction. Bill Fairchild Franklin, TN
**************************************Check out AOL's list of 2007's hottest products. (http://money.aol.com/special/hot-products-2007?NCID=aoltop00030000000001) ---------------------------------------------------------------------- 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
