There have been a lot of useful changes in the z architecture besides the relative and long displacement instructions.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> on behalf of Charles Mills <charl...@mcn.org> Sent: Thursday, May 20, 2021 12:46 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Best catch up resources for MVS / ZOS Technologies If you are a significant coder or maintainer of assembler code, one big improvement that IIRC no one has mentioned is the relaxation of the base register nightmare. You know, where you go to make a one-minute change to some code and you kick it over the 4K boundary and you are faced with three unappealing choices: commit another register to be an additional base, split the module in half, or figure out some hack that gets some big data area out of the basic 4K range. The solution is the relatively (ha ha) new branch relative instructions, commonly referred to as jumps due to their Jxx mnemonics -- plus some other "relative" instructions such as LARL. A full tutorial is out of scope for a mailing list e-mail, but the classics comics version is that you replace all of the Bxx instructions with Jxx, move your data areas to the beginning of the CSECT with LOCTR, and your 4K base register issues should go away, pretty much for good. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Steve Estle Sent: Monday, May 17, 2021 6:42 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Best catch up resources for MVS / ZOS Technologies Hello Everyone in Mainframe Land, I've been out of the mainframe world since about 2001, but spent the prior 20 years immersed in that world working with everything from MVS/370 to MVS/ESA and VM, performance and capacity planning disciplines across a variety of situations in the IT Services and consulting spaces. I, am, now as a "IT Infrastructure Engineer- IBM z/OS Mainframe Engineer" after nearly 20 years of other activities (Project Mgmt, entrepreneur, etc) am about to potentially come back into a new mainframe role and I need to catch up as quickly as possible. Any suggestions on ways to fill in the gaps for ZOS, ZVM, hardware, performance, etc? Bottom line I'm looking for that gap education to as quickly as possible get up to speed with changes in platforms since 2001. If prefer to call - all my info is below. ---------------------------------------------------------------------- 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
