I don't recall coding V=R for any address space, but when we first got into internal DR via XRC between data centers around Y2K, we were forced to carve out DR LPARs from existing production boxes. We would configure storage offline from a large production LPAR in order to IPL DR LPARs in the newly available storage. In order to get that to work reliably, we had to define the storage segment as reconfigurable at POR, which I understood to isolate the storage as if V=R. Details are fuzzy, but the process was discouraged although supported by IBM; without it, CF STOR offline might never succeed.
Thankfully we are way past those constraints. . . J.O.Skip Robinson Southern California Edison Company Electric Dragon Team Paddler SHARE MVS Program Co-Manager 323-715-0595 Mobile 626-543-6132 Office ⇐=== NEW robin...@sce.com -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Steve Thompson Sent: Thursday, June 08, 2017 6:48 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: (External):Re: curious: Anybody still use ADDRSPC=REAL ? On 06/08/2017 11:45 AM, John McKown wrote: > This still seems to be supported in z/OS 2.2. Does anyone need to run > a program V=R in today's world? I'm just curious because this support > seems to be a "waste" of protect keys 10 through 15. Of course, if > those keys were "freed up", what could they be used for? > IBM Prolog for 370 (MVS) used them and it was a V=V program product. It had originally used Key9, but CICS pushed the development group and it got changed. Seemed that when Prolog was run in a CICS space it caused CICS problems by making a page here and there key9. The keys were set to assist the engine in determining when a heap or stack was about to overflow. For either one, the first time it PIC4ed it was noted that garbage collection had to be done. If it fell back below the "warning" page, the flag was reset. If it got up to and hit the second page, then it began cleanup and shutdown due to lack of memory for heap or stack, which ever it was that had run out of room. All of this was done to make it run as much as possible like it had under VM. As a result, IBM's Prolog on the MVS platform was much faster than any competitors (or so I was told in those days). That is as much as I can remember. I wrote the CHANGKEY code, cross-memory charge back SMF record, and SVC for it back in 1991. I haven't seen any of it since. Regards, Steve Thompson ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
