Talk:OS/360 and successors

message: Potential editors may find user:Chatul/References to be of use. Shmuel (Seymour J.) Metz Username:Chatul (talk) 11:07, 27 June 2010 (UTC)
thread_title: Comments

message: I don't think it's wholly unreasonable to tag this with :Category:Software engineering disasters - although now that I look at the contents of that category, I'm reconsidering! It was extremely late, extremely over-budget, extremely over-sized - you name it, along almost every axis it was a nightmare. A smaller company might have been sunk by such a problem - and many were, by smaller ones! Brooks himself had to step down from running the entire System/360 project to overseeing OS/360 to try and pull their irons out of the fire. Yes, it eventually got going, and was not too bad - but as Milo Medin's saying goes, "with enough thrust, anything will fly". Noel (talk) 03:49, 17 August 2005 (UTC)
replies: text: I have no idea what you are talking about. Sam Tomato (talk) 02:03, 2 May 2017 (UTC)
thread_title: A disaster?

message: After a big edit of MVS I concluded that the whole set of articles about IBM mainframe operating systems from System/360 onwards needed to be re-structured to  minimise overlap and to make clearer the evolutionary relationships between these operating systems (notably in memory management, which is historically a major distinguishing feature). There is already some support for this proposal. Please add comments at Talk: MVS. Philcha 23:56, 20 October 2007 (UTC)
thread_title: Restructure of articles about IBM mainframe operating systems

message: As part of the proposed restructure of articles on IBM mainframe operating systems (above), I've rewritten Job Control Language to: cover IBM's DOS/360 and its descendants as well as OS/360 and its descendants; focus more on the facilities and flavour of the 2 JCLs rather than on details of  some statement types and some of their options. Please comment in Talk: Job Control Language. I'd be particulary grateful for more info on DOS/360 and its descendants, especially after 1980 - I only used DOS JCL a handful of times, and only in the late 1970s.
The rewrite does not currently take account of Truthanado's point in Talk: Job Control Language about use of "JCL" by computer suppliers other than IBM, which may entail further restructuring of articles about JCLs.Philcha 00:00, 21 October 2007 (UTC)
thread_title: Rewrite of [[Job Control Language]] in progress

message: Per discussion in Talk:History of IBM mainframe operating systems: proposition was to move OS/360 to a better name OS/360 and successors. No need for two articles with almost exactly the same topic. --Kubanczyk (talk) 15:39, 24 November 2007 (UTC)
replies: text: Oops, I thought I'd made OS/360 redirect to OS/360 and successors. Must have forgotten click "Save". I'm doing it now. Philcha (talk) 15:45, 24 November 2007 (UTC)
replies: text: Not too great. To remind you, the normal process of changing a page name is through a "move" function. There is a help there, which also explains why what you have done is not advisable. --Kubanczyk (talk) 16:11, 24 November 2007 (UTC)
replies: text: Thanks, will use "move" in future. Philcha (talk) 17:52, 25 November 2007 (UTC)
thread_title:  Merge with [[OS/360]] 

message: IBM maintained for a while that PCP, MFT and MVT were just different configurations of the same kernel (OS/360 Introduction), but that is not technically credible:
*PCP (one job at a time) needs only one set of all the control blocks needed to define a job, and no precautions against 1 job interfering with another (memory, files, etc.).
*MFT needs a fixed number of sets of control blocks; and needs precautions against inter-job interference.
*MVT needs to allocate an indefinite number of sets of control blocks dynamically; and needs the precautions against 1 job interfering with another. Dynamic allocation means the top-level control blocks of each job will be scattered around in memory and therefore need to be linked list; while in MFT a simple fixed-length array would suffice.
In fact IBM gave the game away - OS/360 Introduction says "there are two configurations of the [OS/360] control program: ..." (MFT and MVT), which admits that PCP was different.
I'll rephrase accordingly. Philcha (talk) 22:02, 25 November 2007 (UTC)
replies: text: Clarify, what are you talking about? What game? My previous point was not to force OS/MxT names too much, that's all. At least not without explaining to a reader that those were neither separate OSes or separate releases. It is per official creator's docs. --Kubanczyk (talk) 22:48, 25 November 2007 (UTC)
replies: text: "there are two configurations of the [OS/360] control program: ..." (MFT and MVT) implicitly admits PCP was different; if PCP was just another configuration of the same kernel, OS/360 Introduction should have said "there are three' configurations of the [OS/360] control program: ..." Re MFT and MVT note at the wording in the article - "IBM maintained that ..." is very neutral. Philcha (talk) 17:41, 26 November 2007 (UTC)
replies: text: Is this by any chance your original research? --Kubanczyk (talk) 00:23, 27 November 2007 (UTC)
replies: text: The reasoning about the control blocks is, but the quote is from [OS/360 Introduction and clearly excludes PCP. Another IBM doc (ref in article) describes MFT and MVT as "separate versions". Philcha (talk) 07:54, 29 November 2007 (UTC)
replies: text: When discussing the status of various OS/360 options it is important to pay attention to the release that the manuals you are reading from are for. In particular, GC28-6534-3 ia for Release 21, after IBM had dropped support for PCP. Look at, e.g., the Release 13 manuals. Shmuel (Seymour J.) Metz Username:Chatul (talk) 02:20, 20 November 2011 (UTC)
thread_title: Variants of OS/360

message: Support, but let's wait a while for another opinion. --Kubanczyk (talk) 23:04, 25 November 2007 (UTC)
thread_title:  Merge with MFT (operating system) 

message: Oppose keep it as subordinate per Wikipedia:Summary Style; there is very specific info on that article; it would feel awkward on this page. --Kubanczyk (talk) 23:04, 25 November 2007 (UTC)
thread_title:  Merge with [[OS/VS1]] 

message: Support, but let's wait a while for another opinion. --Kubanczyk (talk) 23:04, 25 November 2007 (UTC)
thread_title:  Merge with [[MVT]] 

message: Strong oppose keep it as subordinate per Wikipedia:Summary Style; there is very specific info on that article; it would feel awkward on this page. --Kubanczyk (talk) 23:04, 25 November 2007 (UTC)
thread_title:  Merge with [[MVS]] 

message: Better merge with MVS per above. Wasn't that the re-implementation of I/O subsystem? Introduction of subchannels/CHPIDs/...? --Kubanczyk (talk) 23:04, 25 November 2007 (UTC)
thread_title:  Merge with [[MVS/XA]] 

message: Better merge with MVS per above. --Kubanczyk (talk) 23:04, 25 November 2007 (UTC)
thread_title:  Merge with [[MVS/ESA]] 

message: Oppose keep it as subordinate per Wikipedia:Summary Style; there is very specific info on that article; it would feel awkward on this page. --Kubanczyk (talk) 23:04, 25 November 2007 (UTC)
replies: text: Yes you are right. Once again: Wikipedia:Summary Style. This guideline says that you can build a history here and have some detailed pages, too. --Kubanczyk (talk) 10:38, 26 November 2007 (UTC)
replies: text: Kubanczyk, can you please clarify your last post. Do you mean you agree with the whole of what Martin Packer says (merge all except z/OS, which is also what I'd like to do) or are you still opposing merging in OS/390? Philcha (talk) 17:44, 26 November 2007 (UTC)
replies: text: Hmm lets see... "Putting them together gives a nice sense of history: Them building on one another." -> "Yes you are right. ... you can build a history here and have some detailed pages, too". I agreed with Martin's last sentence, not with the merge proposition. --Kubanczyk (talk) 00:20, 27 November 2007 (UTC)
thread_title:  Merge with [[OS/390]] 

message: Oppose. It may be desirable, in time, to work together :  MVS, MVS/XA,
MVS/ESA, anything beginning with MVS. That is the keyword that people will use first. z/OS should be kept separate, with just a mention of it at the end to direct the user.
Reasons for keeping MVS as separate are numerous. In the working world, systems programmers refer to all versions as MVS only. Next, there are thousands of copies of MVS still running, esp. outside the USA, but even here. Mainframes are not like PC's when it comes to upgrading. It takes an installation years to plan the conversion, get educated, and if hardware upgrades are dictated, wait in line for IBM factories to fill the order and then install difficult equipment and work out chilling requirements.
Finally, data centers have a saying, "don't go first." Any new thing like z/OS is viewed with dark suspicion. Every program in the installation - typically thousands - will be recompiled and tested on the new system.
So I think the term MVS is being used, it is probably the most-used IBM term along with CICS and VTAM. And people will type it in as their search. <User: S.Byczynski, Systems Programmer, Dec. 22, 2008, user>  —Preceding unsigned comment added by 4.238.136.107 (talk) 03:01, 23 December 2008 (UTC)
thread_title: merge with OS/390

message: I plan to add an OS/360 timeline to this article, based on IBM 360 Operating Systems Release History, and wonder whether those data also belong in the IBM Mainframe Operating Systems infobox. Would that be TMI there? Shmuel (Seymour J.) Metz Username:Chatul (talk) 11:41, 27 June 2010 (UTC)
thread_title:  Timeline data only here or also in IBM Mainframe Operating Systems infobox 

message: User:TeleComNasSprVen has added a merge template to OS/VS2 (SVS). That proposal should be considered in the context of the other OS/360 descendants, e.g., if OS/VS1 is merged here then SVS should be also, if not, not. Shmuel (Seymour J.) Metz Username:Chatul (talk) 15:53, 18 August 2010 (UTC)
replies: text: Yes, but this also follows from your edit which added the OS/VS2 to the merge template here. :| TelCoNaSpVe :| 16:00, 18 August 2010 (UTC)

text: OS/VS2 (SVS) is quite a substantial article so it would be a tricky merge. For the sake of convenience rather than any content considerations I've removed the merge tag.--Salix (talk): 13:01, 28 November 2010 (UTC)
thread_title:  Proposed merge with OS/VS2 (SVS) 

message: I added a footnote explaining that while OS/360 was originally announced as a batch operating system, IBM later added interactive facilities. Should I add manuals for CRJE and ITF to References and link to the citations from the footnote, or is that TMI? Shmuel (Seymour J.) Metz Username:Chatul (talk) 21:58, 28 February 2011 (UTC)
thread_title:  References for components mentioned only in footnotes? 

message: The  tag for MVT is inappropriate; the cited article has less detail on MVT than the OS/360 article does. Shmuel (Seymour J.) Metz Username:Chatul (talk) 22:52, 16 November 2011 (UTC)
replies: text: Is that a bug or a feature?  I.e., should Multiprogramming with a Variable number of Tasks give more detail on MVT than the MVT section of this article (so that this article gives a summary and points to the MVT article), or should the stuff in the MVT article be absorbed into the MVT section of this article and Multiprogramming with a Variable number of Tasks changed to redirect to that section? Guy Harris (talk) 01:50, 17 November 2011 (UTC)
replies: text: I see a lot of merging discussion, and I'm coming to it late, but I submit that the OS/360 variants shared most of the code, with a few, tho major, pieces different.  I'd like to see PCP, MFT, and MVT here with the separate articles being redirects, basically I agree with Guy.Peter Flass (talk) 03:53, 17 November 2011 (UTC)

text: IMHO it doesn't make any sense to give details in separate articles on PCP, MFT, MFT II and MVT, aince the overwhelming majority of the OS/360 code base is common to all, and most of what does not exist in PCP is common to MFT II and MVT. As an illustration of this, I've used PCP logic manuals as a guide to MVT code and MVT logic manuals as a guide to PCP code, in cases where IBM had not added relevant information at the same level of detail. Shmuel (Seymour J.) Metz Username:Chatul (talk) 02:03, 20 November 2011 (UTC)
thread_title:  Inappropriate {{tl|main}} tag 

message: OK, it sounds as if User:Chatul thinks the right thing might be to move the stuff from Multiprogramming with a Variable number of Tasks here and make Multiprogramming with a Variable number of Tasks just a redirect to the MVT section of this page.  Is that correct?  If so, it sounds reasonable to me; here's the place to discuss that. Guy Harris (talk) 02:47, 20 November 2011 (UTC)
replies: text: Yes. There's very little material in the MVT article, and much of the detail that could reasonably be added also applies to either MFT 2 or to both MFT and PCP.Shmuel (Seymour J.) Metz Username:Chatul (talk) 00:50, 21 November 2011 (UTC)

text: Done. Peter Flass (talk) 00:33, 3 August 2013 (UTC)
thread_title:  Merger proposal 

message: was the max number of jobs/tasks really unlimited?  I'm sure there was a limit - was it a sysgen option?  or was it indirect limited by some other resource ( number of entries in a table e.g.)? Peter Flass (talk) 18:46, 6 August 2013 (UTC)
replies: text: There was a limit of 15 Initiators due to the 4-bit storage protect key. There was also a total limit of 52 for MFT II, but that did not apply to MVT. For Both MFT II and MVT, the 16 MiB address limit imposed a practical limit on the number of partitions/regions. For both MFT II and MVT, the size of the system queue area specified during SysGen also imposed a practical limit on the number of subtasks. Shmuel (Seymour J.) Metz Username:Chatul (talk) 00:44, 8 August 2013 (UTC)
replies: text: As well as I remember, the lower limit on REGION is the size of the initiator itself.  So, 16MB/(initiator size) or, as noted, 15 protect keys, would be the limit.  Gah4 (talk) 22:59, 3 September 2017 (UTC)
thread_title:  unlimited? 

message: Hello fellow Wikipedians,
I have just modified  on OS/360 and successors. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
*Added archive https://web.archive.org/web/20090304014628/http://www.zjournal.com/index.cfm?section=article&aid=293 to http://www.zjournal.com/index.cfm?section=article&aid=293
*Added archive http://web.archive.org/web/20051013071230/http://www.jaymoseley.com:80/hercules/vstutor/vstutor.htm to http://www.jaymoseley.com/hercules/vstutor/vstutor.htm
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replies: text: The first archive link works; the second one might have worked, but was unnecessary - the page moved on Jay Moseley's site, it didn't disappear, so I put the new link in and got rid of the archive link.  (Perhaps the first reference is still there on enterprisesystemsmedia.com, but I couldn't find it.) Guy Harris (talk) 19:24, 20 July 2016 (UTC)
thread_title:  External links modified 

message: Quoting: Experience indicated that it was not advisable to install OS/360 on systems with less than 256 KB of memory,  As well as I know, PCP is supposed to be able to run in 64K.  It is likely slow running that way, and so might not be advisable, unless one wasn't in a hurry to see results. (That is, 20K for PCP, 44K for user program. Gah4 (talk) 23:03, 3 September 2017 (UTC)
replies: text: PCP was used this way to run a single dedicated software package. Attached Support Processor is one example, I believe there were others.  I think this fell by the wayside later. Peter Flass (talk) 00:52, 4 September 2017 (UTC)
replies: text: One that I know is that PL/I (F) was designed to run in 44K, with PCP on a 64K machine. I don't know that it would be fun to run that way, it might take days to compile a small program.  At the end of every run, PL/I (F) tells you the minimum region size to keep the symbol table in memory (instead of disk).  I suspect that RPG was more useful in 64K. But yes, MFT in 256K might not be so bad. Gah4 (talk) 05:27, 4 September 2017 (UTC)
replies: text: We could IPL MFT in 128 KiB, but that wasn't suitable for production. Similarly, we could IPL MVT in 256 KiB but that didn't leave room for a reasonable mix of regions. With 256 KiB for MFT and 512 KiB for MVT performance was adequate. Shmuel (Seymour J.) Metz Username:Chatul (talk) 14:32, 7 September 2017 (UTC)

text: All the "F"s. I don't think there was a FORTRAN(F), but I know there was COBOL. I seen to recall even a COBOL(E)!Peter Flass (talk) 11:32, 4 September 2017 (UTC)
replies: text: Yes all the "F"s, but fitting a full PL/I compiler in 44K is somewhat harder than RPG.  There are also ALGOL F and Assembler F. As well as I know, the E level are for DOS/360.  And getting the linkage editor to fit in 44K isn't easy, and so it puts much on disk, and is slow. Gah4 (talk) 20:03, 4 September 2017 (UTC)
replies: text: Not to beat the topic to death, the D compilers were DOS, I used to think the  D stood for DOS, but now realize it's the memory size. I looked this up and see an Assembler(E), COBOL(E), and FORTRAN(E), all for OS, along with Linkage Editor (E).  Peter Flass (talk) 21:49, 4 September 2017 (UTC)
replies: text: I suppose I never used an OS/360 system that small.  I always thought that they were for DOS.  I do remember a system with a high priority job class for up to 128K and 15 seconds, and sometime using it to get jobs through faster. I thought that 64K (20K for PCP and 44K for user program) was small enough. I never did get to use DOS. Gah4 (talk) 04:07, 5 September 2017 (UTC)

text: At ADR we ran PL/1 (F) under PCP quite nicely in 128 KiB, and I know of installations running PCP in less than 64 KiB, although, of course, they were restricted to E level compilers.. Is there any reason not to revert the change? Shmuel (Seymour J.) Metz Username:Chatul (talk) 19:37, 5 September 2017 (UTC)
replies: text: I think I tried once to run PL/I (F) in 44K on MVT, but you can't make the REGION that small for MVT. I wanted to see the message at the end.  I did, not so many years ago (well, about 20) run PL/I (F) on an AT/370 with VM/PC, which I believe runs in 512K real storage, and it was very slow. Another message from the compiler tells the available storage, virtual under VM/CMS.  I always wondered if it had to allocate all that, to see how much it was, and how long that took. Gah4 (talk) 22:32, 5 September 2017 (UTC)
replies: text: Actually, you could have a small region in MVT; the scheduling included a region swap. AT/370 ran VM/PC, not OS/360; presumably your virtual machine was large enough to run the CMS compilers, but the processor was still fairly slow and the paging device was nothing to write home about. Shmuel (Seymour J.) Metz Username:Chatul (talk) 14:32, 7 September 2017 (UTC)
replies: text: The story I remember at the time, was that you can't make REGION smaller than the size of the initiator, and that was more than 44K.  Yes, the comparison with VM/PC isn't fair. The way CMS allocates storage, and also the way it does LINK, is different enough. But it was two different things I tried with that compiler, some years apart. Gah4 (talk) 18:28, 7 September 2017 (UTC)
replies: text: To be more precise, a batch job couldn't have a region smaller than what the Initiator needed, but a started task, e.g., SYSOUT Writer, could. If you hav a copy of the MVT job management PLM, the key terms are "L-shaped task" and "IEFSD263". Shmuel (Seymour J.) Metz Username:Chatul (talk) 20:01, 11 September 2017 (UTC)
replies: text: Best explanation that I have seen for the difference between batch job and started task. I only tried once to run PL/I (F) in a small region on MVT, which I suspect is once more than anyone else. I suspect around release 21, if that matters. Gah4 (talk) 22:43, 11 September 2017 (UTC)

text: Maybe just tone it down to "not recommended" or somesuch. Peter Flass (talk) 22:07, 5 September 2017 (UTC)
thread_title:  256K 

message: I've started writing OS/360 and successors#Structure, interface and logic, with the intention of adding a similar section to MVS that links to OS/360 and successors#Structure, interface and logic rather than repeating details. I'm soliciting the following
#Editors interested in adding material
#Guidance on the structure of the section
#Guidance on the appropriate level of detail
#Secondary sources to supplement the primary sources that I have.
I've concentrated on MVT; PCP and MFT are very similar, and I'm concerned that a proper discussion of MVS would make the article too large. --Shmuel (Seymour J.) Metz Username:Chatul (talk) 18:01, 23 May 2022 (UTC)
thread_title:  New section Structure, interface and logic 

message: I am planning to add text that will cite multiple sections of each source. While I could get better appearance using  with R-style shortened references, it is far less work to add a definition list| to OS/360 and successors#Manuals, to include  in each  template and to refer to them with ,  and  in . For the easier option, I might code:
</blockquote>
 Bytes 8-23 read and transfer to the bootstrap record{{sfn|IPL|p=3|loc=THE INITIAL PROGRAM LOADER}} cylinder 0 track 1, which in turn reads and transfers to the IPL Loader. 
 ===Manuals===
 ;IPL
 ;{{cite manual
  | title       = IBM System/3S0 Operating System - Initial Program Loader and Nucleus Initialization Program - Program Number 360S-CI-535
  | id          = GY28-6661-5
  | date        = March 1972
  | edition     = Sixth
  | ref         = {{sfnref|IPL}}
  | url         = http://bitsavers.org/pdf/ibm/360/os/R21.0_Mar72/plm/GY28-6661-5_Inital_Program_Loader_and_Nucleus_Initialization_Program_Rel21_PLM_Mar72.pdf
  | work        = Program Logic
  | publisher   = [[IBM]]
  | access-date = May 23, 2022
 }}
 :MVTSUP
 : {{cite manual
  | title       = IBM System/360 Operating System - MVT Supervisor
  | id          = GY28-6659-7
  | date        = May 1973
  | edition     = Eighth
  | url         = http://bitsavers.org/pdf/ibm/360/os/R21.7_Apr73/plm/GY28-6659-7_MVT_Supervisor_PLM_Rel_21.7_May73.pdf
  | ref         = {{sfnref|MVTSUP}}
  | work        = Program Logic
  | access-date = May 23, 2022
 }}

Rendering as
Bytes 8-23 read and transfer to the bootstrap record cylinder 0 track 1, which in turn reads and transfers to the IPL Loader.
Manuals
 
;IPL
:
;MVTSUP
: 
Any thoughts on whether it is okay to use the second approach so that the backlinks will be automatic? --Shmuel (Seymour J.) Metz Username:Chatul (talk) 13:18, 29 May 2022 (UTC)
thread_title:  Citation structure for multiples sections in same source