On 12 May 2008 11:33:26 -0700, in bit.listserv.ibm-main you wrote: >Edward E Jaffe wrote: > >> That is -- and AFAIK has always been -- the VIO trade-off. CPU time for >> clock time. > >Yes, that's right. And VIO should be compared and contrasted with other >DIM techniques for Batch. I've a feeling I wrote a blog post about it a >few months ago. I should've because I used to present on VIO - especially >the DFSMS management thereof.
If z/OS had FBA, could VIA be a lot more efficient CPU wise? Is some of the CPU time associated with IO hidden in general overhead non-task attributable while VIO attributes all CPU to the task? > >The "DIM Coffee Table" book came about as the result of a number of >studies Development did - in the late 1980s. I DIDN'T participate. But it >led onto residencies I DID participate in. Anyhow the book documented many >performance tests that mapped out the performance characteristics >(including CPU) of many DIM techniques. > >And, as noted, the reason there's the CPU cost is the emulation of disk >devices - rather than the "block mode" operation of eg VSAM LSR. > >I also note that, like some other techniques, VIO is usually seen as a >more or less "write once then read once" use of memory. I.e. not dense in >terms of I/Os avoided per MB of memory deployed. I wonder if the economics >of today make that much less of an issue. I think the answer would have to >be that (UK) :-) English word "somewhat".* > >Martin > >Martin Packer >Performance Consultant >IBM United Kingdom Ltd >+44-20-8832-5167 >+44-7802-245-584 >[EMAIL PROTECTED] > > > >* "Somewhat" is the younger sibling of "it depends" and the (less evil) >twin of "quite". :-) > > > > > >Unless stated otherwise above: >IBM United Kingdom Limited - Registered in England and Wales with number >741598. >Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU > > > > > > >---------------------------------------------------------------------- >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 ---------------------------------------------------------------------- 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
