Shmuel Metz , Seymour J. wrote:
My recollection is that the original virtual storage announcement for S/370 already used the term MVS for OS/VS2 R2. However, you will still see remnants in the code of the original names, AOS/1 and AOS/2.
some number of customers had been doing stuff to make MVT run better in a cp67 (on 360/67) virtual machine ... including various things related to virtual memory. there was a period when we were making regular trips from cambridge to pok to participate in 370 architecture meetings ... especially related to virtual machine and virtual memory operation ... and would periodically knock around 706 machine room in the evenings where AOS prototype was being built ... crafting virtual memory on the side of MVT for what was to become SVS. Ludlow(?, i'm pretty sure i remember his name) was doing a lot of the work. Part of the effort involved taking the (virtual to real) channel program translator/builder from CP67 (CCWTRANS) and cobbling it into the side of MVT (i.e. a lot of AOS ... instead of running MVT under cp67 virtual machine virtual memory ... was hacking various pieces of cp67 virtual memory support into the side of a MVT kernel ... especially the channel program translator ... which was some amount of fairly complicated code, involving interpreting the virtual channel program, making a shadow, finding all the "data" virtual pages, fixing them in core ... and using the "real" addresses). recent thread discussing patching CCWTRANS to handle ISAM and other self-modifying channel programs i.e. CCWTRANS built a "shadow" of the "applications" virtual channel program ... with "real" addresses ... and ran the "shadow" channel program ... any dynamic modifications that an application did to the "virtual" channel program wouldn't actually involve the channel program being executed. http://www.garlic.com/~lynn/2007e.html#14 Cycles per ASM instruction http://www.garlic.com/~lynn/2007e.html#17 A way to speed up level 1 caches http://www.garlic.com/~lynn/2007e.html#19 Cycles per ASM instruction A slightly different issue I had was with the POK performance modeling group that was trying to come up with virtual page replacement algorithms. They eventually decided on including some optimization feature that I claimed that would totally distort "least recently used" assumptions related to page replacement. They did it anyway ... and it wasn't until well into MVS release cycle in the late 70s ... that it dawn on them that they were selecting high-use LINKPACK shared executable pages for replacement before private, lower-used application data pages. lots of past posts related to page replacement algorithms http://www.garlic.com/~lynn/subtopic.html#wsclock as well as old email on the same subject http://www.garlic.com/~lynn/lhwemail.html#globallru past posts in this thread: http://www.garlic.com/~lynn/2007d.html#48 IBM S/360 series operating systems history http://www.garlic.com/~lynn/2007d.html#51 IBM S/360 series operating systems history http://www.garlic.com/~lynn/2007d.html#65 IBM S/360 series operating systems history http://www.garlic.com/~lynn/2007d.html#69 IBM S/360 series operating systems history http://www.garlic.com/~lynn/2007d.html#72 IBM S/360 series operating systems history misc. pasts posts taking ludlow's name in vain: http://www.garlic.com/~lynn/2000c.html#34 What level of computer is needed for a computer to Love? http://www.garlic.com/~lynn/2001b.html#18 Linux IA-64 interrupts [was Re: Itanium benchmarks ...] http://www.garlic.com/~lynn/2001i.html#37 IBM OS Timeline? http://www.garlic.com/~lynn/2001i.html#38 IBM OS Timeline? http://www.garlic.com/~lynn/2001l.html#36 History http://www.garlic.com/~lynn/2002l.html#65 The problem with installable operating systems http://www.garlic.com/~lynn/2002l.html#67 The problem with installable operating systems http://www.garlic.com/~lynn/2002p.html#49 Linux paging http://www.garlic.com/~lynn/2002p.html#51 Linux paging http://www.garlic.com/~lynn/2003k.html#27 Microkernels are not "all or nothing". Re: Multics Concepts For http://www.garlic.com/~lynn/2004e.html#40 Infiniband - practicalities for small clusters http://www.garlic.com/~lynn/2005b.html#49 The mid-seventies SHARE survey http://www.garlic.com/~lynn/2005f.html#47 Moving assembler programs above the line http://www.garlic.com/~lynn/2005p.html#45 HASP/ASP JES/JES2/JES3 http://www.garlic.com/~lynn/2005s.html#25 MVCIN instruction http://www.garlic.com/~lynn/2005t.html#7 2nd level install - duplicate volsers http://www.garlic.com/~lynn/2006b.html#32 Multiple address spaces ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
