Bill, This is brand new information, but I am not sure that it is correct. You state that simply butting PLPA and Common up against one another will cause ASM to treat them as one single dataset. I really don't think this is correct.
AFAIK the Seldom Ending Channel Program running to the Common Page Dataset will complete for any access to another dataset on the volume that wants to use that exposure. It doesn't matter if it is the PLPA page dataset or a backup of my CD collection titles. On a dedicated volume, the Seldom Ending Channel Program completes less often because the one Cyl PLPA minimises the activity to PLPA. Doesn't matter if it adjacent to Common, or on the last CYL of the volume - it will still cause the Common Page Dataset Channel Program to delete. Greg Dyck posted a discussion on Seldom Ending Channel Program seven years ago, which included his advice on configuring PLPA and Common Page Datasets. http://bama.ua.edu/cgi-bin/wa?A2=ind9809&L=ibm-main&D=0&O=D&X=2DEDDB1329D229 429A&Y=ronhawkins%40i-cable.com&P=46510 is an interesting read. (Watch the wrap). It also reminded me that long running ASM Chains are not a good thing. Until the Channel Program ends or suspends none of the page-ins in that chain are available to use. It's like a train - doesn't matter how many carriages there are, everyone finishes the journey at the same time. Ron > > Reducing seeking was not the only driver for their recommendation to place > the PLPA and COMMON page data sets adjacent to each other. The Seldom > Ending > Channel Program used by ASM is allowed to end even more seldom if the two > data sets are allocated contiguously. However, the increase in software > and > elapsed time overhead necessitated by more frequently ending the SECP is > very > small. > > Bill Fairchild > ---------------------------------------------------------------------- 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
