Well, XA+ machines only supported 4K pages / 1M segments and not 2K pages / 64K segments. Then DAS and Access register additions. The 43xx series only supported a single virtual address space, like DOS/VSE. 3090s were the only processors to support Vector instructions, and op codes were re-used in z series.
On Tue, Sep 1, 2020 at 4:20 PM Tony Thigpen <t...@vse2pdf.com> wrote: > > I was thinking more along the lines of things that prevented earlier > operating systems from even IPLing on newer boxes. Such as z13 is the > last processor to have ESA/390 mode. I also have it in my head that at > some point there were changes to the page size and virtual storage > tables that caused havoc. > > Tony Thigpen > > Seymour J Metz wrote on 9/1/20 3:30 PM: > > Typically the new features reqiured by a level set were added over several > > generations, and each generation added more than one feature. > > > > > > -- > > Shmuel (Seymour J.) Metz > > http://mason.gmu.edu/~smetz3 > > > > > > ________________________________________ > > From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on behalf of > > Tony Thigpen <t...@vse2pdf.com> > > Sent: Tuesday, September 1, 2020 3:25 PM > > To: IBM-MAIN@LISTSERV.UA.EDU > > Subject: Architectural Level Sets > > > > IBM has had several Architectural Level Set points where there were > > significant changes to the CPU that prevented earlier operating systems > > from running on them. > > > > What CPU's were involved with each level, and what was the real > > underlying item changed on the CPU that forced a new level? (Let's keep > > it limited to z990 and newer.) > > > > > > Tony Thigpen > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
