Re: Virtual Lock File
Scott, Try adding the following two (2) commands to your PROFILE EXEC -- CP SET RUN ON SET AUTOREAD OFF John P. Baker Chief Software Architect HFD Technologies -Original Message- From: The IBM z/VM Operating System [mailto:IBMVM@LISTSERV.UARK.EDU] On Behalf Of Wandschneider, Scott Sent: Tuesday, March 08, 2011 12:58 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Virtual Lock File I have a SVM called VDISKS the creates and initializes a virtual lock file for four VSE guest to use. After a short time, VDISKS is logged off by the system. All is fine if at least one VSE remains logged on, however if all are logged off the virtual lock file goes away also. How can I keep VDISKS from being logged off by the system? * * * Top of File * * * USER VDISKS $SECRET$ 4M 4M BG 90 *NAME: VIRTUAL_DISKS ACCOUNT SYSTEMS SUPPORT COMMAND SET RUN ON IPL CMS MACH ESA XAUTOLOG AUTOLOG1 MAINT CONSOLE 0009 3215 T OPERATOR SPOOL 000C 2540 READER * SPOOL 000D 2540 PUNCH A SPOOL 000E 1403 A LINK MAINT 0190 0190 RR LINK MAINT 019D 019D RR LINK MAINT 019E 019E RR MDISK 0191 3390 499 001 PKSCMS MR ALL WRITE MULTIPLE MDISK 0222 FB-512 V-DISK 6208 MWV ALL *DVHOPT LNK0 LOG1 RCM1 SMS0 NPW1 LNGAMENG PWC20101121 CRCc PROFILE EXEC Z1 V 130 Trunc=130 Size=14 > |...+1+2+3+4.. 0 * * * Top of File * * * 1 /* */ 2 'CP SPOOL CONSOLE START MAINT CLASS M' 3 Trace I 4 'EXECIO * CP (STRING Q' USERID() 5 PULL @RESPONSE 6 PARSE VAR @RESPONSE @USERID . @TERMID 7 IF @TERMID = 'DSC' THEN DO 8EXEC INITVDSK 9SLEEP 05 SEC 00010'CP SPOOL CONSOLE CLOSE' 00011EXIT 00012 END 00013 SET PF12 RETRIEVE 00014 EXIT 00015 * * * End of File * * * INITVDSK EXEC Z1 V 130 Trunc=130 Size=8 > |...+1+2+3+4 0 * * * Top of File * * * 1 /* EXEC TO INITIALIZE ALL VDISKS*/ 2 Trace I 3 ERASE DSFOUT OUTPUT A 4 PUSH 'DSFOUT' 5 PUSH 'INITV222' 6 ICKDSF 7 'CP LINK * 222 222 RR' 8 EXIT 9 * * * End of File * * * INITV222 INPUTZ1 F 80 Trunc=80 Size=1 Line=0 Col=1 Alt=0 > |...+1+2+3+4+5+6 0 * * * Top of File * * * 1 INIT UNIT(222) NVFY NOMAP PURGE VOLID(VSELOK) FBAVTOC(6200,8) 2 * * * End of File * * * Thank you, Scott R Wandschneider Systems Programmer 3|| Infocrossing, a Wipro Company || 11707 Miracle Hills Drive, Omaha, NE, 68154-4457|| : 402.963.8905 || :847.849.7223 || : scott.wandschnei...@infocrossing.com **Think Green - Please print responsibly**
Re: VM/CMS Training Material
The CMS Primer still exists. For z/VM V6 R1, the publication number is SC24-6172-00. John P. Baker Chief Software Architect HFD Technologies From: The IBM z/VM Operating System [mailto:IBMVM@LISTSERV.UARK.EDU] On Behalf Of Ed Zell Sent: Monday, February 28, 2011 12:18 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: VM/CMS Training Material Hi David, There used to be a CMS Primer and an XEDIT Primer that were part of the VM library from IBM. We used parts of those books to do our initial training for new mainframe developers. I don't know if they still exist or not, but they covered most of what you are looking for. Ed Zell Illinois Mutual Life (309) 636-0107
Re: Storage Management Enhancement Ideas (was: VM lockup due to storage typo)
Bill, You may well be correct. Of course, that permits me to pose the question of how such a condition could effectively be avoided. Ideas, anyone? John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Bill Holder Sent: Monday, September 21, 2009 11:32 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Storage Management Enhancement Ideas (was: VM lockup due to storage typo) These are very interesting ideas, but I suspect (no way to prove, since no doc will be forthcoming) that the hang was not a paging issue, but rather a central storage fragmentation issue involving attempts to allocate four contiguous frames for region and segment tables. Don't let me throw cold water on the current discussion, though, I just wanted to point out that all of the interesting paging ideas probably wouldn't help the situation that triggered this entire discussion. - Bill Holder, z/VM Development, IBM
Re: Storage Management Enhancement Ideas
Alan, I disagree. Yes, you still have the possibility of a resource shortage. However, partitioning provides the installation more flexibility in protecting critical resources. As far as how should CP respond, if sufficient page space is unavailable within a particular backing storage pool according to the criteria set forth, then the request (LOGON, DEFINE STORAGE) should be denied. John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Alan Altmark Sent: Monday, September 21, 2009 2:03 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Storage Management Enhancement Ideas And does not address the core issue: At some point, there is a shortage of resources. How should CP respond? o Deny the request? o Wait for the resources to be available? o Steal the resources from someone else? You can partition and reserve all the resource you want, but eventually you run out. Alan Altmark z/VM Development IBM Endicott
Re: Storage Management Enhancement Ideas (was: VM lockup due to storage typo)
Rob, In many instances you would be correct. However, in this case, the decisions targeting a specific backing storage pool are made either at LOGON time or during a DEFINE STORAGE command. This is actually a very simple approach to the problem. Also, once the backup storage pool placement decision is made, there should be no impact on the instruction path length. John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Rob van der Heij Sent: Sunday, September 20, 2009 4:26 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Storage Management Enhancement Ideas (was: VM lockup due to storage typo) On Sat, Sep 19, 2009 at 6:21 PM, John P. Baker wrote: I don't like the idea to use only a subset of your paging capacity for part of the workload. It's not just about space but also about throughput. This is imho a very complicated approach to exclude some (small) important users from an OOM killer. The real question is whether you can do an OOM killer at all and achieve something useful by doing so. Most performance tuning gets harder when you split resources and consumers in different groups and manage them separately. Sharing is easier with large numbers. Rob -- Rob van der Heij Velocity Software http://www.velocitysoftware.com/
Re: Storage Management Enhancement Ideas (was: VM lockup due to storage typo)
Rich, Something else that comes to mind is that page space spills into spool space when page space fills up. It may be worth considering to provide system configuration options (both a default and for each backing storage pool) that would determine whether page over-allocation could be spilled into spool space. John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Rich Smrcina Sent: Saturday, September 19, 2009 1:19 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Storage Management Enhancement Ideas (was: VM lockup due to storage typo) Nicely written -- Rich Smrcina Phone: 414-491-6001 http://www.linkedin.com/in/richsmrcina Catch the WAVV! http://www.wavv.org WAVV 2010 - Apr 9-14, 2010 Covington, KY
Storage Management Enhancement Ideas (was: VM lockup due to storage typo)
All, Since we have now beat the issue of storage management to death, I would like to set forth some concrete ideas for consideration. First, it has been pointed out that it may not currently be possible to LOGON to MAINT or OPERATOR or to some other service machine in order to diagnose the problem. I recommend that the idea of splitting page space into multiple pools be considered, where individual users can be assigned to different pools. For the purposes of discussion, let us consider that following enhancement: . In the SYSTEM CONFIG file o DEFBACKSTGPOOL pool-id-8 o BACKSTGPOOL pool-id-8 volser-6 . In the CP directory o OPTION BACKSTGPOOL pool-name-8 . Extend the CLASS B CP QUERY command o QUERY BACKSTGPOOL user-id-8 o QUERY DEFBACKSTGPOOL . Extend the CLASS B CP SET command o SET BACKSTGPOOL user-id-8 {DEFAULT | pool-name-8} . Extend the CLASS G CP QUERY command o QUERY BACKSTGPOOL Each paging volume will be allocated to a specific backing storage pool. A LOGON will be rejected if the backing storage pool does not exist. The SET BACKSTGPOOL command will be rejected if the backing storage pool does not exist. Second, provide a specification on whether a virtual machine requires full backing storage for its defined memory size. . In the SYSTEM CONFIG file o DEFBACKSTG {SYSTEM | VMSIZE} . In the CP directory o OPTION BACKSTG {DEFAULT | SYSTEM | VMSIZE} . Extend the CLASS B CP QUERY command o QUERY BACKSTG user-id-8 o QUERY DEFBACKSTG . Extend the CLASS B CP SET command o SET BACKSTG user-id-8 { DEFAULT | SYSTEM | VMSIZE} . Extend the CLASS G CP QUERY command o QUERY BACKSTG If BACKSTG is set or defaulted to SYSTEM, page allocation will continue to operate as it does today. If BACKSTG is set or defaulted to VMSIZE, there must be available within the backing storage spool sufficient space to accommodate the entirety of the specified VMSIZE, otherwise the LOGON, DEFINE STORAGE, or SET BACKSTG command will be failed. The SETBACKSTG command will force a virtual machine reset to occur. These changes will address some of the issues raised. I am certain that other changes would be required, and that other ideas should be considered. Please post your ideas. Don't hesitate to point out any problems. John P. Baker
Re: VM lockup due to storage typo
Personally, I have always preferred BAC (Broken As Coded). John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Schuh, Richard Sent: Friday, September 18, 2009 11:58 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: VM lockup due to storage typo Hey Zeke Boyes, who is Bill Schuh? I don't even know of a relative by that name :-) Working as Documented is another version of WAD. My stance is that if the system dies because of a design "feature", then perhaps that feature ought to be reconsidered. Certainly, there is no way to anticipate all possible feature failures, but when one comes up that is preventable, then the design ought to be tweaked. All of the discussion about whether it is or is not a DOS is totally irrelevant, especially to those who have been victimized. (I thought that Lyn Hadley eliminated WAD and BAD from the IBM vernacular years ago.) Regards, Richard Schuh
Re: VM lockup due to storage typo
First, since CP should know at all times how much space of each category (PAGE, SPOL, etc.) is allocated, it should be able to immediately reject any request (LOGON, DEFINE STOR, etc.) where the amount of storage requested exceeds the amount of secondary storage configured. Second, since CP "should" know at all times how much space of each category (PAGE, SPOL, etc.) is in use, it should be able to immediately reject any request (LOGON, DEFINE STOR, etc.) where the amount of storage requested exceeds the amount of secondary storage available. If this is not happening, I would argue that the situation should be APAR'able as a system integrity bug. Now, we can debate whether pages allocated, but not used, should be counted. Should such pages require secondary storage backing availability, or should secondary storage backing availability be required only when the page is used? Should this be a system configurable option? Should this be a virtual machine configurable option? John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Lee Stewart Sent: Tuesday, September 15, 2009 4:56 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: VM lockup due to storage typo Gee, I guess we're in good company! ;-) It does seem to me that CP should be smart enough to look at a 175GB real storage, 4GB Xstor, and xx number of page packs and say not in our wildest dreams can we run an 8TB virtual guest... Or maybe at the point that the 8TB guest starts choking off all other activity and wildly filling page space Lee
Re: IBM DS6800 caching
Rob, AFAIK, CA-DYNAM/T does NOT use reserve/release. Tom, What was the setting of the SHARE= parameter when the catalog was initialized? John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Rob van der Heij Sent: Wednesday, July 29, 2009 2:36 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: IBM DS6800 caching I am grateful that my most intimate recollections about DYNAM-T are paged out.. But from the little that is left, I believe that DYNAM-T is using reserve / release for their shared catalog access. Make sure you configuration is such that those are not silently absorbed by CP when it thinks there is no real need for them (pun intended). Rob
Re: Not Receiving VMESA-L Posts
Mike, On my system, that is all that has come through. It appears to have been a quiet weekend. John P. Baker From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Michael Coffin Sent: Monday, June 15, 2009 10:56 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Not Receiving VMESA-L Posts Hi Folks, Is it just me, or is anybody else not receiving all posts from VMESA-L? Starting last Friday 6/12/2009 the posts stopped arriving - only 3 posts on 6/12, 1 on 6/13, 1 on 6/14 and one so far today 6/15. I know that there are more because some of the ones that have arrived are responses to posts I never received. I checked my SMTP mail logs and don't see anything from uark.edu being rejected. -Mike
Re: IBM 1401: was Re: z/VM 5.4 VSAM question - PJBR
When I started out in programming, over 40 years ago, the distinction was that an emulator was hardware assisted, while a simulator was pure software. John P. Baker From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of Huegel, Thomas Sent: Tuesday, May 26, 2009 10:24 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: IBM 1401: was Re: z/VM 5.4 VSAM question - PJBR Now I beg the question, 'What is the difference between an "emulator", and a 'simulator"?'. I always thought they were differentiated in that the emulator required a hardware feature and a simulator was all software. Is that correct?
Re: How Many Files Can Be on a Minidisk Before It Cannot be ACCESSed?
Can you migrate the application to SFS? You could have a 2nd-level directory for each month, and a 3rd-level directory for each day of the month. John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of James Stracka (DHL US) Sent: Wednesday, April 29, 2009 11:36 AM To: IBMVM@LISTSERV.UARK.EDU Subject: How Many Files Can Be on a Minidisk Before It Cannot be ACCESSed? We have a minidisk with 152715 files on it and another with 126996 files. Since the FAT is below the line, we cannot access both of these minidisks concurrently. DMSACP109S Virtual storage capacity exceeded Given that the "S" and "Y" disks as well as CMS take storage below 16M, does anybody have an idea of approximately how many files will go on a minidisk (I suppose an SFS directory will have the same concern) before it cannot be accessed?
Re: How Many Files Can Be on a Minidisk Before It Cannot be ACCESSed?
John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:ib...@listserv.uark.edu] On Behalf Of James Stracka (DHL US) Sent: Wednesday, April 29, 2009 11:36 AM To: IBMVM@LISTSERV.UARK.EDU Subject: How Many Files Can Be on a Minidisk Before It Cannot be ACCESSed? We have a minidisk with 152715 files on it and another with 126996 files. Since the FAT is below the line, we cannot access both of these minidisks concurrently. DMSACP109S Virtual storage capacity exceeded Given that the "S" and "Y" disks as well as CMS take storage below 16M, does anybody have an idea of approximately how many files will go on a minidisk (I suppose an SFS directory will have the same concern) before it cannot be accessed?
Re: IUCV - What's wrong with this picture?
Gary, I suggest that your point about the server needing to know immediately about a client logoff is a good argument for a system-supplied notification service, similar to ENF on z/OS. For example, let's say that we create an *NOTIFY system service. A virtual machine, appropriately authorized is allowed to connect to the *NOTIFY service, and by sending properly constructed messages, register its desire to begin receiving, or to discontinue receiving, specific types of event notifications. Certainly, LOGON and LOGOFF notifications should be available. Other event types come to mind, such as varying a central processor online or offline, or varying a device online or offline. I feel certain that others here can recommend other event types that should be monitorable. Then, whenever an event of the requested type occurs, all registered listeners would receive the notification on the *NOTIFY path. This would at least provide a mechanism by which one of your requirements could be addressed. John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Gary M. Dennis Sent: Wednesday, August 27, 2008 11:59 AM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: IUCV - What's wrong with this picture? Thanks for the response on the IUCV questions. I have included below item 6 from the thread origin and a snippet from John Baker's response. Maybe I should have placed more emphasis on item 6. The server machine is going to be updating the buffer areas in all the connected client machines. Therefore, he server machine needs to know immediately when one of the guests is quiescent or logged off. IUCV will inform the server when a connection is severed. The guest machines can set in indicator in an area monitored by the server to indicate that they have begun a normal closedown *but* the "fall-off_the page" case is when a machine is logged off and the server attempts to access the buffers in a machine that no longer exists. John made a good argument for temporary IUCV connections. In that case the best way to make a determination on the active state a diagnose that issues a query command for the user in question? --. .- .-. -.-- Gary Dennis
Re: IUCV - What's wrong with this picture?
Since you indicate low traffic volume, maintaining a permanent connection between the server and each client seems to me to be excessive. Alternatively, I would propose a somewhat different approach. The server should have configuration parameters specifying the maximum number of concurrent connections, the statistical notification interval, as well as other necessary information. The server should maintain a list of all potential clients. Each entry should include a last connection timestamp. Each client should have configuration parameters naming the server, the statistical notification interval, as well as other necessary information. If the server has a task to be distributed to a client for processing, it should examine in client table for an available client, establish an IUCV connection, and transfer to the client the information necessary to initiate the transaction. The connection should then be severed pending transaction completion or an intermediate statistical report. If a connection cannot be established because too many connections are active, the event requirement should be posted for retry after a specified interval. If a connection cannot be established because the client does not respond, some form of recovery (i.e., FORCE/XAUTOLOG) sequence may be appropriate. If a statistical report is required and has not been received by the server, the server should attempt to establish an IUCV connection to the client for that purpose, again following the general procedure outlined above. On the client side, on a regular interval, the client should attempt to establish an IUCV connection to the server for the purpose of reporting statistical information, again following the general procedure outlined above. Maintaining thousands of IUCV connections may not have a significant impact on real storage considering the vast amounts of memory now available on zSeries processors. However, searching through all of those linked lists WILL have a performance impact, and is totally unnecessary. John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Gary M. Dennis Sent: Monday, August 25, 2008 1:24 PM To: IBMVM@LISTSERV.UARK.EDU Subject: IUCV - What's wrong with this picture? Assumptions: 0. A VM server machine 1. A cluster of client virtual machines (possibly thousands) 2. n buffers are allocated for each client virtual machine 3. Each buffer contains table elements that require (a) Element ageing (b) Element deletion when invalidated by: 1. lack of use 2. client machine request (c) Compression as buffer fragmentation occurs 4. Each client virtual machine in the cluster is connected via IUCV to the server virtual machine. 5. IUCV traffic between the server machine and client machine is extremely low volume. Initial call, termination call, intermittent statistics call. 6. After the initial call, the server virtual machine will maintain the buffer table entries in each client virtual machine without additional IUCV interaction. Now the questions: 1. Does IUCV infrastructure overhead specifically associated with number of connections become prohibitive at some well known point? 2. Has anyone had experience with an application having a high IUCV connection count like this? If so, what was that experience? Again, the traffic incidence per connection is very low but the number of connections is potentially very high. Thanks --. .- .-. -.-- Gary Dennis
Re: Next Baybunch at IBM San Francisco-Friday Aug 6
Since there is NO Friday, August 6th until 2010, we will assume a TOD malfunction, and reschedule for Friday, August 8th, 2008. John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Pamela Christina - warm and sunny Endicott NY Sent: Wednesday, August 06, 2008 6:34 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Next Baybunch at IBM San Francisco-Friday Aug 6 For those of you who near San Francisco Bay area this Friday and who are interested in hearing z/VM and Linux presentations. The next Baybunch meeting is on Friday August 6 at IBM San Francisco - 425 Market St. Send an RSVP email to Karen Reed at [EMAIL PROTECTED] Meet with the Baybunch user group on Friday, August 8 Alan Altmark presents: - z/VM Platform Update - Hear about z/VM V5.4 (just announced!) - Securing Linux with RACF Jim Elliott presents: - Linux on System z: A strategic Details in the PDF: http://www.vm.ibm.com/events/bayb0806.pdf Regards, Pam C
Re: Nice idea in blog: Should we toss x86 architecture
It sounds like Mantissa is on the road that I am interested in. Specifically, I would like to see IBM incorporate the capability into z/VM to dispatch virtual machines on disparate architectures made available via co-processing capabilities, such as those currently provided for encryption, and where communication between the mainframe and the co-processor is handled using the SIGA (Signal Adapter) machine instruction. Of course, I would like to see the SIGA instruction documented in the z/Architecture Principles of Operation publication. I can envisage a z/VM machine running z/Linux, z/OS, z/VM (2nd level), z/VSE, and thousands of copies of Windows. We can hope that the version of Windows will be more stable than Windows Vista. Moving that kind of instability into z/VM is not particularly attractive. Otherwise, on a conceptual basis, it opens up many possibilities. John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Gary M. Dennis Sent: Tuesday, July 22, 2008 2:03 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Re: Nice idea in blog: Should we toss x86 architecture This was our post to the zd net blog. "Maybe we already have. In Q1 2009 Mantissa will deliver a system that permits unaltered Windows operating systems to run under z/VM. Using a desktop appliance running RDC, users will be able to connect to their virtual Windows images running in the VM environment. Goodbye desktop hardware, remote maintenance, high power consumption, machine order lead time. z/VOS began with the observation that most Windows workstations do practically nothing 95% of the time and we were so intrigued with the idea of being able to actually run an intel-based operating system under IBM VM that we never looked back. VM provided a natural platform for development of this product. The product has been a bear for the development group but the thought of being able to run 3000 copies of Windows on one System z so fascinated the team that we needed very little additional incentive. Let's hope IBM can ramp up System z production." Why wait until 2016? --. .- .-. -.-- Gary Dennis Mantissa Corporation
Re: Allocating Cyl Zero as Perm (Was: Performance toolkit under zVM 5.3)
Every site that I have been associated with has operated under the premise that, with the exception of full pack minidisks, cylinder zero (0) is ALWAYS allocated PERM, and a one (1) cylinder reserved space minidisk is placed in the directory for each volume in recognition of that fact. Since at least VM/ESA 2.4.0, and probably significantly earlier, CP does not use the page slots which would be located on cylinder zero (0) track zero (0), see HCPMSACR MACRO for more information, so there is no likelihood of the volume label being overwritten by CP. However, a problem can arise if paging or spooling space is allocated starting on cylinder zero (0), and subsequently that space is reallocated for user minidisks without taking into account the need to allocate a one (1) cylinder placeholder. To my mind, best practices should dictate either (1) page and spool space will ALWAYS be segregated onto volumes used solely for that purpose, or (2) all volumes SHALL be allocated with a permanent one (1) cylinder type(PERM) placeholder at cylinder zero (0). John P. Baker -Original Message- From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Thomas Kern Sent: Tuesday, June 24, 2008 5:35 PM To: IBMVM@LISTSERV.UARK.EDU Subject: Allocating Cyl Zero as Perm (Was: Performance toolkit under zVM 5.3) I have never seen a problem with CP stepping on the Label. I have stepped on it myself and seen other inexperienced people step on it. That is why I always allocate cylinder zero of a VM volume as perm and allocate a one cylinder minidisk owned by VMDASD there. That is the "best practices" guideline that I follow. /Tom Kern
Re: MITIME settings are being set by ?
Brian, According to the CP Commands and Utilities Reference, the following defaults are provided: . DASD 00:15 . GRAF 01:10 . UR 01:00 . TAPE 10:00 . SWITCH05:00 . MISC 12:00 For DASD and TAPE, the supplied defaults will be used if and only if the subsystem does not return a primary timeout value. The supplied defaults, or for DASD and TAPE, the primary timeout value returned by the subsystem, will be put into place following an IPL. Subsequently, an authorized operator may change the values by way of a SET MITIME command. For DASD and TAPE subsystems, check the appropriate subsystem documentation for the primary timeout value returned, if any. John P. Baker Systems Engineer HFD Technologies From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On Behalf Of Hamilton, Brian Sent: Monday, January 21, 2008 10:39 AM To: IBMVM@LISTSERV.UARK.EDU Subject: MITIME settings are being set by ? Where would I find the initial or override settings for MITIME's? I've looked in the SYSTEM config and on the AUTOLOG1 or 2 ids but I don't see any SET commands. e.g. MITIME ON 2060-2085 00:40 MITIME ON 2000-201F 00:40 MITIME ON 086262:30 MITIME ON 086120:50 MITIME ON 086020:50 MITIME ON DASD00:15 MITIME ON GRAF01:10 MITIME ON TAPE10:00 MITIME ON UR 01:00 MITIME ON SWITCH 05:00 MITIME ON MISC12:00
Re: Does anyone know of a documented case of VM being penetrated by hackers?
I am not aware of any documented case where VM has been penetrated by hackers (a term to which I take strong exception). The use of a looping channel program is not a system penetration as such, as the person responsible was also authorized to the system, but was rather a misuse of the authority granted to that person. Every case of an external break-in to a VM system has been due to either: 1) Not changing the IBM-supplied installation passwords; or 2) The use of poor password choices (an actual example was a Userid of BIGMAC and a Password of BURGER). 3) The unauthorized provision of a password to an external user by an internal user. There have been numerous cases of bugs in the VM code bringing down the system. For example, when IBM first introduced the "Remote Dial" capability (VM/SP r2?), I was at a site which participated in the BETA of that code. If one graphic terminal on one remote 327x controller dialed into a virtual graphic controller on a virtual machine, everything worked fine. Unfortunately, this was apparently the only configuration tested by IBM. For example, if two graphic terminals on two different remote 327x controllers dialed into the same virtual graphic controller on the same virtual machine, the whole VM system came crashing down around our ears. It took months to track down the problem and get it resolved. I suppose that a remote user could have dialed in maliciously in order to cause a system failure. However, I don't feel that such a scenario passes the smell test. As I indicated, I am aware of no case where a VM system has been "penetrated" by hackers (objection reiterated). John P Baker
Re: http://www.vm.ibm.com/
Can't get to it. DNS works, but the site appears to be down. John P Baker > -Original Message- > From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On > Behalf Of Alan Ackerman > Sent: Thursday, January 11, 2007 6:17 PM > To: IBMVM@LISTSERV.UARK.EDU > Subject: http://www.vm.ibm.com/ > > I cannot get to <http://www.vm.ibm.com/>. Can others? Does anyone remembe > r > the IP address for www.vm.ibm.com? > > I am getting: > > Gateway Timeout > The following error occurred: > [code=DNS_TIMEOUT] A DNS lookup error occurred because the request time > d > out during the lookup. > > Please contact the administrator > > This sounds like a DNS problem, but I don't know if it is at our end or > > not.