As far as I know, MVS always used only 4K pages in DAT. My evidence is that the oldest MVS IEAVNIP0 source that I can find unconditionally uses 4K pages in DAT. What is your evidence?
The hardware storage keys were still on a 2K basis, so two SSKs were done for each 4K page, until the >16MB of real storage support was added to the 3033. That introduced the ISKE and SSKE instructions, which required only on SSKE for a 4K page. The MVS SP1.3 JBB1326 version of IEAVNIP0 tried an SSKE, and if it didn't program check, assumed that the machine had the new instructions and DAT support for >16MB of real stroage. Jim Mulder z/OS Diagnosis, Design, Development, Test IBM Corp. Poughkeepsie NY "IBM Mainframe Discussion List" <IBM-MAIN@LISTSERV.UA.EDU> wrote on 09/02/2020 12:27:34 AM: > From: "Joe Monk" <joemon...@gmail.com> > To: IBM-MAIN@LISTSERV.UA.EDU > Date: 09/02/2020 01:29 AM > Subject: Re: Architectural Level Sets > Sent by: "IBM Mainframe Discussion List" <IBM-MAIN@LISTSERV.UA.EDU> > > "MVS didn't use 2KiB pages," > > Yes, MVS 3.8J does use 2KB pages. > > Joe > > On Tue, Sep 1, 2020 at 7:20 PM Seymour J Metz <sme...@gmu.edu> wrote: > > > MVS didn't use 2KiB pages, so I never paid any attention to whether the > > 4341 or 3081 had them, but MVS/XA required DAS. Access registers came > > later, on the 3090, and were part of ESA. > > > > The 4341 most definitely was not limited to a single address space; It ran > > MVS/SP 1.3 just fine. > > > > > > -- > > Shmuel (Seymour J.) Metz > > http://mason.gmu.edu/~smetz3 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
