[email protected] (McKown, John) writes: > Perhaps "not financially viable". "We" complain about how much z/OS > costs right now. Imagine the howls of rage if IBM were to increase the > cost of z/OS by 10% (to pick a round, random, number) and say that it > was to allow z/OS to use FBA devices. PDSes are a integral part of > z/OS (like it or not). Many people still dislike PDSEs. PDSs can't > exist without CKD. So to go "pure" FBA (to remove the dependency on > ECKD) would require a huge investment. Now, to add FBA support for > access methods which are inherently FBA compatible (VSAM et al.) would > likely be easier.
as I've mentioned a number of times before ... long ago and far away the group told me that even if I provided them fully integrated and tested FBA support ... I still needed a $26M business case to cover training and documentation ... and I could only use incremental new sales in the business case (say $200M-$300M additional disk sales) ... and wasn't able to use life-cycle cost savings (that were enormous ... both for the company as well as customers ... totally dwarfing everything else). misc. past posts mentioning ckd, fba, multi-track search, etc http://www.garlic.com/~lynn/submain.html#dasd recent "MVM" thread ... from the definition in IBM Jargon as the original name for MVS, there was an enormous simulation layer added going from MVT to OS/VS2 ... basically, initially CCWTRANS was imported from CP67 (virtual machine vm370 percusor on 360/67)into EXCP processing which had to scan the passed channel program and build a duplicate with real addresses for execution. http://www.garlic.com/~lynn/2011d.html#71 Multiple Virtual Memory http://www.garlic.com/~lynn/2011d.html#72 Multiple Virtual Memory http://www.garlic.com/~lynn/2011d.html#73 Multiple Virtual Memory Now since all the "real" CKD disks have been FBA for a long time, then for decades, there has been a fairly large simulation layer (in the controller) that takes channel programs and perform emulated CKD function. There is roughly equivalent in various of the 370 simulators that run on intel & other platforms, with their own software layer simulating CKD function on FBA devices. So possible transition phase (decades ago) would have been to enhance official access methods to support native FBA ... ... and then include a multi-track search emulation layer in the EXCP channel program translation ... doing the same exact function currently performed in the lower layers, since *ALL* disks have been native *FBA* for some time (somebody has to be doing all that simulation). That would go a long way to accelerating weaning the dependency off multi-track search. -- 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: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
