> -----Ursprungligt meddelande----- > Från: IBM Mainframe Discussion List [mailto:[email protected]] För R.S. > Skickat: den 13 februari 2012 15:49 > Till: [email protected] > Ämne: Re: SV: SV: Archaic allocation in JCL (Was: Physical record size > query) > > W dniu 2012-02-13 15:21, Thomas Berg pisze: > > (This is an answer also to Vernooij.) > > > > Please consider what You do manually when the space is to small (e g B37 > etc.), or You just is unsure: You try a bigger allocation, maybe also > extend (or reduce) the secondary amount. And repeat. Often many times. > > Would it be a problem if this (more or less) is automated ? Hm ? > > > > Technically I suppose it's solved by an initial "virtual" allocation > filling a buffer in memory. > > Then a disk allocation is done at a threshold with e g 5 cyl. > > If that is not enough, add 4 times the amount, 20 cyl. > > Repeat this until finish. > > Release unused space (from the last add). > > > > This is just an example, it can be done much more sophisticated by the > OS. > > > > And the limit of allocation should be set by userid or datasetname > properly. Or maybe by a (e g) LIMIT= keyword. > > > > (I'm using the JCL case as an illustrative example, it should of course > be general system interface.) > > > Actually space abends in my environment are very very rare. Time and > experience were needed to go there, but the experience + SMS facilities > + DFSMShsm causes x37 abends almost non-existent. > > As I said, z/OS storage requires different approach. On Windows system > programmer opens the file and writes to it. On z/OS he has to answer the > question: HOW MUCH DATA DO YOU EXPECT TO BE WRITTEN. The answer can be > veeeery imprecise, but it is required. > > Could it be better? I think so. What about unlimited number of extents? > Or at least, let's say, 3000 per volume? What about multi-volume > PDS(E)s? What about FBA disks? > WAKE UP! > ;-)
I refuse! :) (In my life space abends occurs regularly, often caused by circumstances beyond my control.) BTW, You latter suggestions is not bad - but You didn't go far enough! There should unlimited number of *everything*! Don't make artificial limits. Regards, Thomas Berg _________________________________________ Thomas Berg Specialist A M SWEDBANK ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
