Talk:MVS

message: > Japanese mainframe manufacturers Fujitsu and Hitachi both repeatedly and illegally obtained IBM's MVS source code and internal documentation in one of the 20th century's most famous cases of industrial espionage.[citation needed]
I found some references to this from old ComputerWeek articles from 1980s, but even those don't read quite like the above, sounds like a much more complex case.... the above sounds like something out of IBM lawyers.  — Preceding unsigned comment added by 2601:18F:600:E20:99A6:13B5:83E8:B008 (talk) 01:45, 4 September 2016 (UTC)
replies: text: Here's a U.S. Congressional hour of hearings testimony, including FBI, fines, etc.: http://www.fas.org/irp/congress/1989_cr/h890712-japan.htm  — Preceding unsigned comment added by 72.251.58.10 (talk) 18:06, 18 January 2017 (UTC)
thread_title:  Non-POV claims 

message: OS/360 right up to MVS/SP only supported 24-bit addressing. As the underlying hardware progressed it supported 31-bit (XA and ESA) and now (as z/OS) 64-bit addressing were added.
Should this say "it supported 32-bit (XA and ESA)"? No, because the 32nd bit, the top/left-most bit is used to distinguish between 31-bit and 24-bit addressing modes, as well as being used as a special "end-of-list" marker known as the VL-bit. Both adressing modes can be intermixed in the same program, as documented in the respective "Princple of Operations" manual. Special instructions were introduced to let any program switch from one addressing mode to another AndreasCA (talk) 18:31, 26 October 2008 (UTC)
replies: text: There was an early attempt at 32-bit addressing in the System/360 Model 67, and the weird bugs deriving from unsigned addresses in a milieu where sign bits hadn't previously participated were legendary horror.  When Extended Addressing (XA) came it did in 31-bit form to avoid repeating those problems.  When System/390 extended the addressing to 64 bits, a lot of us said "surely you mean 63 bits - no sign, right?".  The response from IBM was that they had spent so much time and effort dealing with public relations etc. fallout from the 31-vs.-32 bit decision that there was only one acceptable answer to the 63-vs.-64 bit question. RossPatterson 03:48, 12 April 2006 (UTC)
replies: text: Interesting. How did 64-bit systems handle variable-length argument lists in subroutine calls (see below re CALL macro)?Philcha 05:37, 19 October 2007 (UTC)

text: That's right. More specifically, from DOS/360 and OS/360 onwards  subroutine calls passed the addresses of their arguments (like references in C); the last of a variable-length set of arguments had the high bit set to 1 (by the CALL macro in Assembler; by compilers for high-level languages). Philcha 05:37, 19 October 2007 (UTC)
thread_title:  31-bit addressing 

message: MVS will run the processor at 100% utilization while still performing real work. Try that on UNIX or Windows based systems.
:More precisely, MVS requires hardly any tuning to run the processor at 100% utilization while still performing real work. In the early 1970s the large UK clearing banks ran their overnight systems at 100% just to get all the work done, but that required careful system design and heavy tuning of MVT. Philcha 06:19, 19 October 2007 (UTC)
thread_title:  Benefit of running MVS now z/OS 

message: --------------------------------------------------------
Long discussion on the topic, with a plan of new structure, has been moved to Talk:History of IBM mainframe operating systems. Please continue there.
--------------------------------------------------------
--Kubanczyk 12:46, 24 October 2007 (UTC)
thread_title: Need to restructure IBM operating system articles?

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 23:47, 20 October 2007 (UTC)
thread_title: Rewrite of [[Job Control Language]] in progress

message: Some time ago there was a push to standardize the names of articles related to exclusive IBM products (OS/2 → IBM OS/2).  I've moved a few of the more obvious ones... would the move here be appropriate?  /Blaxthos 17:04, 28 October 2007 (UTC)
replies: text: How this ummmm "standardization" effort relates to official Wikipedia guideline WP:COMMONNAME? The two seems to be in conflict, aren't they? May I ask about the reasons for this renaming push? --Kubanczyk 17:38, 28 October 2007 (UTC)

text: Please do not rename until merger proposal decided (see below). If the pages are merged, renaming will be unnecessary. Philcha (talk) 21:10, 25 November 2007 (UTC)
thread_title:  Name standardization 

message: To reduce duplication of content re features inherited from MVS's predecessors and to fit into the framework provided by History of IBM mainframe operating systems.  —Preceding unsigned comment added by Philcha (talk • contribs) 21:07, 25 November 2007 (UTC)
thread_title: Merger proposal

message: First, the genealogy of z/OS is a bit longer than the article states. There were also several add-on program products that were eventully meged into the base. Off the top of my head:
* OS/VS2 Release 2 through 3.8
* MVS/System Extensions
** Release 1 based on 3.7 and SU7
** Release 2 (SE2) based on 3.8 and SU64
* MVS/SP Version 1
* MVS/SP Version 2 (MVS/eXtended Architecture)
* MVS/SP Version 3 (MVS/ESA)
* MVS/SP Version 4 (MVS/ESA)
** Release 3 introduced OPEN EDITION (Unix)
* MVS/ESA Version 5
* OS/390 Version 1
* OS/390 Version 2
* z/OS
Unix came in with MVS/SP 4.3, under the name MVS OPEN EDITION.
Several older add-on packages were swallowed up by TSO/E and DFP; the latter was eventually renamed to DFSMS and incorporated several other add-on products. 
Officially Unix System Services does not have an acronym; USS refers to Unformatted System Services, a part of VTAM, and by extension to equivalent services in the TN3270 server. Shmuel (Seymour J.) Metz Username:Chatul (talk) 14:11, 7 July 2010 (UTC)
replies: text: I've edited the article to address some of the above. In the process I noticed a claim that MVS was the most common mainframe operating system. I've always understood the DOS/VSE, VSE/AF, VSE/SP. VSE/ESA and z/VSE were each, in their day, more popular. If anybody has any documentation one way or the other, please add a citation. Shmuel (Seymour J.) Metz Username:Chatul (talk) 15:44, 8 July 2010 (UTC)
replies: text: Where does MVS#MVS/370 fit into this? I've just merged the article in and I can't find many references to it.--Salix (talk): 12:52, 28 November 2010 (UTC)
replies: text: As mentioned in Talk:MVS/370, IBM introduced the term MVS/370 to refer to all versions of MVS that required S/370 (24-bit address) architecture rather than XA (31-bit addressing) architecture. Shmuel (Seymour J.) Metz Username:Chatul (talk) 12:25, 29 November 2010 (UTC)
thread_title:  History and names 

message: DSS was not qa hypervisor, it was an interactive debugging facility for the operating system. It was much more primitive than the similar TSSS in TSS/360.
Also, IBM killed DSS twice. After the announcement that Selectable Unit 7 would remove support for DSS, the user organization Share passed an Imperative requirement to reinstate DSS, and IBM caved in. Rumor had it thaqt the massive code change required to allow DSS to coexist with SU 7 was actually a single line. Shmuel (Seymour J.) Metz Username:Chatul (talk) 17:46, 20 July 2011 (UTC)
thread_title:  DSS was not a hypervisor 

message: There are several problems with the references to MVS/370 in this article
*MVS/370 refers to all of OS/VS2 (MVS), MVS/SE and MVS/SP Version 1
*MVS/370 has not been supported for decades, so the reference to being supported should be removed.
*The earliest MVS/370 was OS/VS2 R2; the latest was MVS/SP V1.3 (1.3.7?)
Shmuel (Seymour J.) Metz Username:Chatul (talk) 21:22, 16 August 2011 (UTC)
thread_title:  References to MVS/370 

message: My edit summary for my revert of two edits by Rfc1394 was truncated.  In its entirety: "The comparison of PDSs to ZIP files is marginal, ZIP files are not really meant to be updated, whereas PDSs are, and the above/below the line distinction is an RMODE distinction whereas the description describes AMODE differences.".  And to further expand on the AMODE/RMODE thing, the residence mode (RMODE) of an application controls whether it runs below (RMODE(24)) or (potentially) above the line (RMODE(ANY)), whereas the addressing mode defines if the program uses 24 bit (AMODE(24)), 31 bit (AMODE(31)), or in either (AMODE(ANY)), based on the caller.  While a program running AMODE(24) must be RMODE(24), programs running with 31 bit addressing may (and commonly do) run below the line, so that the can be easily called from 24 bit programs.  There are additional complications (newer versions of the OS support 64 bit addressing and programs that have bits loaded into separate areas), but they're not really relevant here.   Rwessel (talk) 05:43, 4 August 2014 (UTC)
replies: text: In addition, AMODE and RMODE are attributes of individual load modules or program objects, not of entire applications. Further, an RMODE(24) AMODE(24) module can still allocate storage above the line, using the appropriate parameters of the GETMAIN or STORAGE macro, and an AMDE(31) RMODE(ANY) module can still allocate storage below the line. Shmuel (Seymour J.) Metz Username:Chatul (talk) 20:42, 4 August 2014 (UTC)
thread_title:  Reverted of good faith edits by Rfc1394 

message: The MVS/SE program products were Extensions (plural); however, the processor feature 3033 Extension Feature is singular. Shmuel (Seymour J.) Metz Username:Chatul (talk) 17:31, 24 January 2017 (UTC)
thread_title:  Clarification of extension versus extensions 

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thread_title:  External links modified 

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replies: text: The first edition is indeed gone from bitsavers, but I notice that the second edition is still there at <http://bitsavers.org/pdf/ibm/370/OS_VS2/Release_3.8_1978/GC28-0984-1_OS_VS2_MVS_Overview_May1980.pdf>. Shmuel (Seymour J.) Metz Username:Chatul (talk) 20:10, 11 January 2018 (UTC)
replies: text: Actually, the first edition is still at bitsavers, but that's a different scan, and doesn't seem to be as good a scan as the archived version. Guy Harris (talk) 20:35, 11 January 2018 (UTC)
thread_title:  External links modified 

message: The lede image showing the Hercules console really seems to hsve nothing to do with MVS. Does some Herculean have a screenshot of an actual MVS console display that could be used instead? Peter Flass (talk) 13:44, 20 June 2019 (UTC)
thread_title:  image 

message: This page seems to go crazy with Safari/iPad - keeps flashing, possibly reloading. This is the only page I’ve seen that this happens to. Peter Flass (talk) 02:52, 28 January 2020 (UTC)
thread_title:  ipad problem 

message: The article has sections called MVS#History and MVS#Evolution of MVS. Either the sections should be merged or the names changed to make it clear who did what to whom. Shmuel (Seymour J.) Metz Username:Chatul (talk) 03:24, 19 July 2020 (UTC)
thread_title:  How does evolution differ from history? 

message: I find the paragraph  in MVS#MVS filesystem to be confusing. I'm not aware of anything called a slash filesystem, and the second sentence is not true. To clarify:
* MVS-OE uses MVS datasets as containers for Unix filesystems.
* A user can specify a path (Unix file) on a DD statement or dynamic allocation.
* In some, but not all, cases, a classic MVS program can use a Unix file.
* IBM has enhance some Unix utilities to support special systax for referring to classic MVS datasets.
* Unix programs that do not use the enhanced library and that have not been modified are not able to use classic MVS datasets
Before I edit that text I want to understand what the author is trying to say. Shmuel (Seymour J.) Metz Username:Chatul (talk) 04:19, 19 July 2020 (UTC)
thread_title:  Confusing text in [[MVS#MVS filesystem]] 

message: I've created an Upgrades to MVS section that lists enhancements that came as optional features or products rather than as new releases or sub-releases. I currently don't show any of the ICRs prior to OS/VS2 Release 3.7. If anybody spots any errors or omissions, or has relevant announcements that they can link to, please edit appropriately. I plan to create subsections for the more important products, probably including DFP, DFSMS, MVS/SP and TSO/E. I will probably describe the products that each replaces as leadins, rather than giving them their own subsections. 
Would the list of Incremental change releases, Field Developed Programs and Program products be better as a collapsible table? Shmuel (Seymour J.) Metz Username:Chatul (talk) 22:31, 2 August 2020 (UTC)
thread_title:  New section Upgrades to MVS 

message: Now that IBM has put up a repository of announcement letters at https://www-01.ibm.com/common/ssi/ going back to 1981, I'm considering building a timeline for selected MVS software, starting with User:Chatul/References as a sandbox. I'm currently thinking of 
* Products in the DF/foo, DFP and DFSMS line
* Products in the MVS/SE and MVS/SP line, through z/OS
* Products in the SCRIPT line
* Products in the SPF line 
* TSO/E
* MVS/XA replacements for free access methods, e.g., BTAM/SP, GAM/SP
* Communications products, e.g., ACF/VTAM
I'd like feedback on
* What products to include or exclude
* Whether to put the timeline in the MVS article or elsewhere
* Whether to put everything in a single table or create multiple tables, either by category or chronology
* Whether to make the table(s) collapsible or sortable?
Thoughts? Shmuel (Seymour J.) Metz Username:Chatul (talk) 17:59, 1 June 2021 (UTC)
thread_title:  Contents, location and organization of timeline? 

message: I've created the article Draft:Data Facility Storage Management Subsystem (MVS), with citations to all of the relevant IBM announcement letters that I could find. Some of the information should fit in well here, although I suggest keeping DFP and DFSMS text short, with a  template once the draft is in the article namespace. --Shmuel (Seymour J.) Metz Username:Chatul (talk) 13:23, 23 June 2021 (UTC)
thread_title:  Copy information from Draft:Data Facility Storage Management Subsystem (MVS)? 

message: There are several issues in the description of recovery in #Evolution of MVS:
There is no mention of Associated Recovery Routines (ARRs), although that might be TMI.
Similarly, there is no mention of the STAI and ESTAI options of ATTACH.
A huge amount of privileged code in MVS runs in TCB mode and is allowed to use  STAE and ESTAE.
Some program checks can be intercepted with SPIE and ESPIE, in which case no is no ABEND to recover from -- Shmuel (Seymour J.) Metz Username:Chatul (talk) 16:02, 6 February 2024 (UTC)
thread_title:  Recovery