-----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Patrick O'Keefe Sent: Thursday, February 22, 2007 2:56 PM To: IBM-MAIN@BAMA.UA.EDU Subject: Re: IBM S/360 series operating systems history
<snip> As I recall, some of the "registers" actually had hard-coded values; they could be used as base registers but little else. I have no idea what happened if you tried storing into them. That alone supports your "grossly incompatable" assertion. It didn't even bother to pretend its linkage conventions were the same as s/360. It used something other than the s/360 linkage instructions BAL and BALR (BAS and BASR, as I recall). <snip> I rarely called other programs, but when I did, I used the basic protocols (R0-R1, R13-R15) with STM/LM, but using halfwords. The BAL/R did not work, because the registers were only halfword size which meant you had no place to store the linkage information. R3-R6 (as I recall, I don't happen to have my Model 20 card/booklet handy) were fixed, R3= x'1000', R4= x'2000' ... I can't remember what happened if you stored into them either (I'm not sure if you got a "HALT" of the SPEC type or what). R1-R2 worked exactly like the PoOP says for the other S/360s when it came to TRT and EDMK. I must disagree with the idea that it was "grossly incompatable" for several reasons: a) BAL code could be moved between the two environments with a few changes (mainly, the half-word register conventions, and using preset registers, which is where I think the R3 for base got started...). And we used a BAL/BALR macro so that we didn't have to change our thinking all the time. b) EBCDIC is EBCDIC between the two machines (no funny stuff as happened between Burroughs' EBCDIC and IBM's) c) RPG moved directly from the Model 20 to any other DOS machine (H & F specs may have needed one or two changes) d) Tapes had the same internal formats between the two systems. e) If you had a large enough model (sufficient memory and some channel feature(s)), you could hang 2311 disks on them and then exchange those with a S/360 using 2311s f) Decimal instructions worked exactly the same, including ED and EDMK Many years after working in a circus bureau, I had the pleasure of being at a certain US Gov't shop, they had two model 20s where they were still exchanging 800/1600 BPI tapes using SL with a JES3 environment. I was the only person there that had any real experience with a 20 to do program patches. Perhaps my definition of gross incompatible is different. But I would call a UNIVAC 1100 grossly incompatible with a S/360 (no real EBCDIC support, data interchange needed to be via 9 bit ASCII, COBOL had to converted to run on IBM from UNIVAC (or Honeywell), CARDs punched on UNIVAC may not even be readable by IBM...). Regards, Steve Thompson ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
