Thanks for that. I'm a new boy, compared with some here. I started on a mixture of VM/370 and MVS/XA. All the new code was AMODE 31 and RENT where it was sensible. We used the new instructions where they helped and the recommended interfaces where it was reasonable.
The old code was 'fun' at times. Like the drive geometry hard-coded into an ancient direct access routine that was almost an access method in itself. And some of the JES exits were old-school works of art :-) Rupert On Mon, 16 Dec 2019, 20:56 Charles Mills, <charl...@mcn.org> wrote: > I would guess most basic applications and simple system utilities from > OS/360 will run unchanged, even in load module form. If you have an IEBCOPY > dump on a medium you can read I would guess you could restore it and run it > under z/OS V2R4. > > That's pretty new source code you show. <g> I don't think of RMODE/AMODE > as old stuff, but I guess it is all relative. Certainly the code you post > below (if completed) would assemble, link and run without error. > > It *is* quite an achievement. I am personally perhaps counter-usual-wisdom > in that I wonder if the 100% slavish compatibility was an over-learning of > the lessons of Future System on IBM's part. I wonder if the guaranteed > compatibility has given customers permission to ignore the platform in > their management thought process. "It will always work whether we invest in > it or not." > > https://en.wikipedia.org/wiki/IBM_Future_Systems_project if you don't > know what I am referring to, especially the last paragraph under Project > End. > > Charles > > > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On > Behalf Of Rupert Reynolds > Sent: Monday, December 16, 2019 12:48 PM > To: IBM-MAIN@LISTSERV.UA.EDU > Subject: Backward compat--how far? > > Another question, purely out of interest: > Can the old MVS/SP code still run unchanged? > I reminisced with a friend about the day he whinged about a 64k code > segment size on Intel micros and I out-whinged him with a 4k code CSECT :-) > > Can a modern z/OS installation still assemble, link and run the old stuff, > such as the typical local utilities we all saw: > > MYPROG CSECT > MYPROG RMODE ANY > MYPROG AMODE 24 > STM 14,12,12(13) > USING ... > > If so, that's quite an achievement, both in the changes and the flexibility > of the original design! > > ---------------------------------------------------------------------- > 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
