On Wed, 6 Feb 2008 07:57:40 -0600, McKown, John wrote: >> -----Original Message----- >> From: IBM Mainframe Discussion List On Behalf Of Phil Smith III >> Sent: Wednesday, February 06, 2008 4:45 AM >> Subject: Re: CPU time differences for the same job >> >> No, you aren't. HPO 3.4 added "Active Wait", which was >> interesting enough that it was granted a patent (cf. >> http://www.freepatentsonline.com/4631674.html). Modern VMs >> use the TPZI instruction (Test Pending Zone Interrupts), >> which basically says "Mr. PR/SM, please wake me up when I >> have something to do". Without it, PR/SM wouldn't work real >> well. (ObAnecdote: there were plenty of DOS-based PC >> programs that polled -- typically for keyboard interrupts -- >> in a fashion conceptually similar to Active Wait, and were >> really poor citizens under Windows until cured.) >> > >[snip] > >> ...phsiii > >TPZI??? Yet another undocumented System z instruction? Ah, yes, that reminded me of where I learned of it. If you want (some) documentation, check the U.S. Patent Office. Do a search on 'TPZI' and you will hit some of the PR/SM filings... and even learn of yet another undocumented (beyond the patents) instruction in patent 4843541: DCSI -- Diagnose Compare and Swap Instruction
(Now if I could just keep the PR/SM stuff in memory and purge the obsolete active wait junk...) I believe that some of it (at least) was also described in an article for the IBM Systems Journal and there was also a very difficult to obtain IBM manual on SIE. I ordered my copy online maybe 12 years ago or so and I was told by IBM that they actually swiped a copy of someone's desk in POK to be able to fulfill my order. (Sorry about that, whomever it was! I still have the pub even though it is pretty long in the tooth now.) -- Tom Schmidt (Thanks, Phil!) ---------------------------------------------------------------------- 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
