Talk:VM (operating system)

message: Well, after all the advertising, some thoughts from a z/VM sysprog...
After some time of getting used to it z/VM is a great system to work on. But, of course, it also has its disadvantages.
On the downside, z/VM can be a real pain for the sysprog staff. Many things have to be done manually, especially when upgrading the z/VM environment to a new release which includes tedious editing sessions merging the old system files with the new ones. IBM doesn't offer a simple procedure for this task, while system maintenance can usually be done with a simple command, SERVICE.
Luckily z/VM features REXX, a great scripting language which is nowadays available for almost any system platform, helping to automate  the upgrade process. Still, since z/VM had'nt been too popular before Linux for z/Series came to existance, there's a serious lack in support and education personnel - any sysprog dealing with z/VM knows most of the IBM people working on z/VM personally. While these guys do a great job supporting customers, IBM would be well advised to recrute new experts in the near future.
What's more: if a customer doesn't stick to the IBM way of doing things (like running only a few z/VM LPARS) it shows an obvious lack of systems management functionality, at least 'out of the box'. There are many inofficial (aka unsupported) tools available from IBM's z/VM website, but their evaluation and installation is completely up to the customer, and you still find yourself coding many small helper utilities, because the things you need are simply non-existant.
Of course, all of this is absolutely transparent to the system images you run on z/VM, but it can occupy the z/VM sysprog quite a bit. Admittedly, it's fun to code on z/VM, but it can be hard to explain this to someone's boss, who has been told (probably by some IBM consultant?) that z/VM can be run absolutely stable (which is true, at least most of the time) and without much effort (which, in my experience, really depends on the given situation).
Compared to PC-based solutions, z/VM is much more powerful, but at the same time, much more complex to maintain. —Preceding unsigned comment added by 84.59.38.230 (talk • contribs) 19:52, 3 November 2006
Moved from the article to here by RossPatterson 01:07, 4 November 2006 (UTC)
thread_title: Some thoughts from a z/VM sysprog

message: I have just finished a reshuffling/rewriting of material from VM and CP/CMS articles. I have tried to incorporate the various comments applicable to this page, though of course there were many issues involved. If you don't see something that you feel was important, naturally please go ahead and make changes. Trevor Hanson 19:39, 3 December 2006 (UTC)
thread_title:  Restructuring of VM and CP/CMS material 

message: I had stated that VM was required for AIX and Linux, but this was just challenged. After some further investigation, I see that I was misinformed. I had been relying on some strong and credible statements to that effect (which of course I can't put my finger on at the moment), but I now see from other sources that this must have been bogus. IBM's installation docs clearly describe native configurations, e.g. http://www.redbooks.ibm.com/abstracts/sg246264.html. There probably have been specific environments or situations where VM was the only way to go, which led to the claims in the sources I had trusted. I agree that the blanket statements here needed to disappear. I have thus removed the remaining claims about VM being necessary. It would be helpful if some good references about native AIX/Linux configurations could be located, particularly from an historical perspective about AIX. Trevor Hanson 18:55, 17 December 2006 (UTC)
thread_title:  AIX/Linux under VM 

message: I am not competent to contribute here, but I wish to point out there are too little dates (years), in this article, so that the timeline of the whole VM story is blurry.   Even the "History" section only has one year:  1972.   You can't figure out what happened later and when.    If the experts could fix this, I'd be very grateful.  —The preceding unsigned comment was added by 212.180.69.18 (talk) 08:24, August 22, 2007 (UTC) 
:Good point. I had been hoping that a current z/VM expert would step in on this page and add some more detail about recent history. I have added the z/VM original release date (October 2000) and a link to IBM's z/VM release history. Plenty of early dates are found in the CP/CMS articles. Details on the middle years between 1972 and 2000 could be beefed up by somebody with the expertise and interest. Most of the release dates should be close to the associated hardware announcements, e.g. the XA versions were linked with the release of XA hardware. On the other hand, there probably aren't too many people who care about specifics on those events. The IBM archives remain the best bet for a timeline of versions. Trevor Hanson 22:34, 22 August 2007 (UTC)
thread_title:  Dates missing 

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

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thread_title: Image copyright problem with Image:ZVMCMS.png

message: The S/370 versions of AIX have been dead for well over a decade; essentially, since the availability of a Unix environment in MVS/ESA SP Version 4. Linux on z, of course, is alive and well.Shmuel (Seymour J.) Metz Username:Chatul (talk) 21:48, 21 September 2010 (UTC)
thread_title: He's dead, Jim - AIX

message: The paragraph about running VM inside VM mentions "The litterature" providing practical examples of nested virtualization "five levels deep". I'm curious to know which litterature that is so that I can find out what the examples were. 88.131.66.80 (talk) 16:13, 19 October 2011 (UTC)
thread_title:  Examples of (deeply) nested virtualization? 

message: In the late 1980's we did some interesting work running CICS directly on VM and also under VM/CMS and VM/PC.  VM/PC doesn't seem to get a mention anywhere although it was a full VM implementation running on 370 order code on the XT or AT/370 hardware.  There were also communications facilities between VM/PC and a host running either VM/CMS or CICS using a DIAG '78' (from memory...) interface.  Does anyone remember more, or have documentation?  — Preceding unsigned comment added by Deasington (talk • contribs) 15:26, 10 July 2012 (UTC)
thread_title:  VM - the missing bits! 

message: Hello fellow Wikipedians,
I have just added archive links to  on VM (operating system). Please take a moment to review my edit. If necessary, add  after the link to keep me from modifying it. Alternatively, you can add  to keep me off the page altogether. I made the following changes:
*Added archive https://web.archive.org/20061018022910/http://www.vm.ibm.com/devpages/christin/vmwebart.html to http://www.vm.ibm.com/devpages/christin/vmwebart.html
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Cheers. —cyberbot IITalk to my owner:Online 05:34, 18 October 2015 (UTC)
thread_title:  External links modified 

message: While Virtual Machine Facility/370 was distributed in source code, IBM instituted a policy of Object Code Only (OCO) for newer, chargeable, software. The FOSS designation would be reasonable for an article on only CP-40, CP-67 and VM/370, but not for an article that covers VM/SP through z/VM. Shmuel (Seymour J.) Metz Username:Chatul (talk) 14:54, 27 March 2019 (UTC)
thread_title:  FOSS? The free base was, but not anything recent 

message: Processor Resource/System Manager (PR/SM) facility on IBM's z line started out as a modified CP on the 3090 using the same SIE instruction as VM/XA MF through z/VM. Should there be a brief description, linking to PR/SM and Logical partition as the main articles? Shmuel (Seymour J.) Metz Username:Chatul (talk) 19:01, 4 September 2019 (UTC)
thread_title:  Should there be a section on PR/SM? 

message: Starting with VM/XA MF, doesn't SIE directly handle the execution of certain privileged instructions, e.g., LPSW? --Shmuel (Seymour J.) Metz Username:Chatul (talk) 20:01, 19 August 2021 (UTC)
thread_title:  Privileged instructions 

message: The lists of operating systems under VM currently have a bold tag with no line break, directly followed by the text for the OS. Would it be better to have description lists, which also bold the tag but put the text, indented, on a new line? E.g.:
Group Control System (GCS)
GCS Provides a limited simulation of the MVS API. IBM originally provided GCS in order to run VTAM without a service OS/VS1 virtual machine and VTAM Communications Network Application (VCNA). RSCS V2 also runs under GCS.
Remote Spooling Communications Subsystem (RSCS)
RSCS provides communication and information transfer facilities between virtual machines and other systems
;Group Control System (GCS)
:GCS Provides a limited simulation of the MVS API. IBM originally provided GCS in order to run VTAM without a service OS/VS1 virtual machine and VTAM Communications Network Application (VCNA). RSCS V2 also runs under GCS.
;Remote Spooling Communications Subsystem (RSCS)
:RSCS provides communication and information transfer facilities between virtual machines and other systems
Does it seem clearer with that formatting? --Shmuel (Seymour J.) Metz Username:Chatul (talk) 14:37, 6 October 2021 (UTC)
thread_title:  Format of OS lists? 

message: Can ACP/TPF run under VM? Peter Flass (talk) 15:04, 7 May 2023 (UTC)
replies: text: I thought that I had responded to this, but my update seems to have disappeared. Briefly, CP-67 should be able to run Programmed Airline Reservations System (PARS), VM/370 should be able to run IBM Airline Control Program (ACP), ..., z/VM is able to run z/TPF. I haven't looked lately, but it used to be that the only way to run TPF on multiple processors concurrently was to run multiple copies under VM. -- Shmuel (Seymour J.) Metz Username:Chatul (talk) 16:43, 8 May 2023 (UTC)
thread_title:  TPF