John wrote: "Under MVS, PAV is under the control of WLM to determine when to create a new alias address to a given base address and then take it back later."
That's only true for dynamic PAV's. If you use static PAV's and make the simpler assumption that amount of data behind the volume is the driving factor, then a mod-9 image needs 3 PAV's to perform as well as a mod-3 and a mod-27 needs 9 PAV's. Using manual tuning to give a somewhat even distribution of I/O, the simple rule-of-thumb may be stoneage compared to WLM, but is still workable. However, I suspect the OCO problem is what's holding things up. The dasd susbsystem business is cutthroat and keeping any advantage is of paramount importance. Its the same as the QDIO OCO issue (except that everyone else is getting out of the mainframe business). ===== Jim Sibley Implementor of Linux on zSeries in the beautiful Silicon Valley "Computer are useless.They can only give answers." Pablo Picasso __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com
