[email protected] (Ed Gould) writes: > We used to run MFT and everyday we changed the partition sizes without > an IPL. > Now if you are saying to change from MFT to MVT then indeed an IPL was > needed, > as well PCP to MFT (or for that matter MVT)? > > The OS is the "key" issue and indeed VM you can "ipl" an OS and it > probably does not require an IPL(machine wise) a virtual machine > needs to be brought in . > > Maybe I am missing some distinction here.
recent post about vm370 handshaking being done at univ. for MVT http://www.garlic.com/~lynn/2012c.html#16 5 Byte Device Addresses? vm370 has function to save an virtual memory image from virtual machine and then restore it using IPL command (using ipl-by-name function) .... sort like checkpoint/restart ... but for system. they identified place in MVT where everything was quiesced and could jump back in ... provided for hot-restart significantly cutting MVT IPL elapsed time startup. note that one of the customers that had been sold 360/67 was boeing huntsville to run tss/360 ... tss/360 was never fully realize ... and many customers ran machine as 360/65 with os/360. boeing huntsville had 360/67 two-processor multiprocessor configurated to run as two independent single processor processors ... with MVT supporting several 2250M1s and long-running graphic applications. The problem was that MVT had a horrible storage fragmentation with long running applications. As a result, Boeing Hunstsville had modified release 13 MVT to run in virtual memory mode but w/o paging. The virtual memory hardware was used to re-order storage addresses as compensation for significant MVT storage fragmentation associated with long running applications. This is similar ... but different to the justification for adding virtual memory as standard to all 370s ... and move from MVT to SVS ... discussed in this past post: http://www.garlic.com/~lynn/2011d.html#73 Multiple Virtual Mmeory .... part of quote in above: Evans around. For reasons unknown to me, the TSO group had the flip charts and wallboard zzzzz used. The clincher was the ability to run 16 initiators simultaneously on a 1 megabyte system, taking advantage of the fact that MVT normally used only 25% of the memory in a partition. The resulting throughput gain (compared to real hardware) was substantial enough to convince Bob. It helped that Tom Simpson and Bob Crabtree had hosted an MFT II system TSS-Style and shown similar performance gains. Of course, since CP67 was a pickup group they weren't considered and we had the OS/VS adventure instead. ... snip ... Simpson and Crabtree had done HASP ... and then Simpson went on to do modified MFT-II implementation using TSS-Style paged-mapped filesystem paradigm called RASP (significant performance advantage over the approach taken by SVS&MVS preseving the OS/360 disk paradigm). This wasn't picked up and Simpson left for Amdahl where he there was "clean-room" do-over. There was legal action about theft of code (even tho there was no intention of ever using RASP) ... and the resulting court audits only found a couple accidental incidents examples of identical code. a couple old email mentioning RASP do-over: http://www.garlic.com/~lynn/2011e.html#email810408 http://www.garlic.com/~lynn/2011e.html#email820907 http://www.garlic.com/~lynn/2011e.htmL#email870302 a few past posts mentioning RASP: http://www.garlic.com/~lynn/2000f.html#68 TSS ancient history, was X86 ultimate CISC? designs) http://www.garlic.com/~lynn/2000f.html#69 TSS ancient history, was X86 ultimate CISC? designs) http://www.garlic.com/~lynn/2000f.html#70 TSS ancient history, was X86 ultimate CISC? designs) http://www.garlic.com/~lynn/2001b.html#73 7090 vs. 7094 etc. http://www.garlic.com/~lynn/2002g.html#0 Blade architectures http://www.garlic.com/~lynn/2002i.html#63 Hercules and System/390 - do we need it? http://www.garlic.com/~lynn/2002j.html#75 30th b'day http://www.garlic.com/~lynn/2002q.html#31 Collating on the S/360-2540 card reader? http://www.garlic.com/~lynn/2003e.html#65 801 (was Re: Reviving Multics http://www.garlic.com/~lynn/2005p.html#44 hasp, jes, rasp, aspen, gold http://www.garlic.com/~lynn/2006f.html#19 Over my head in a JES exit http://www.garlic.com/~lynn/2006w.html#24 IBM sues maker of Intel-based Mainframe clones http://www.garlic.com/~lynn/2006w.html#28 IBM sues maker of Intel-based Mainframe clones http://www.garlic.com/~lynn/2007m.html#69 Operating systems are old and busted http://www.garlic.com/~lynn/2010i.html#44 someone smarter than Dave Cutler http://www.garlic.com/~lynn/2010o.html#0 Hashing for DISTINCT or GROUP BY in SQL http://www.garlic.com/~lynn/2010p.html#42 Which non-IBM software products (from ISVs) have been most significant to the mainframe's success? http://www.garlic.com/~lynn/2011.html#85 Two terrific writers .. are going to write a book http://www.garlic.com/~lynn/2011e.html#26 Multiple Virtual Memory http://www.garlic.com/~lynn/2011e.html#47 junking CKD; was "Social Security Confronts IT Obsolescence" http://www.garlic.com/~lynn/2012.html#67 Has anyone successfully migrated off mainframes? http://www.garlic.com/~lynn/2012.html#69 Has anyone successfully migrated off mainframes? -- virtualization experience starting Jan1968, online at home since Mar1970 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
