"Binyamin Dissen" <[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED]>... > On Wed, 10 May 2006 19:06:47 -0400 Art Celestini <[EMAIL PROTECTED]> > wrote: > > :>I think it's actually non-VSAM, and it's because a lot of applications > :>using EXCP or lower would break. > > :>Such programs normally issue an EOV to cause allocation of a new extent
> :>for an output data set. I suspect most apps would then expect to find > :>a new extent in the extent list (not more space allocated within the last > :>existing extent). I think what IBM could do is to add an option to > :>either OPEN or EOV so the application could say "I can handle Extent > :>Consolidation." Then it could be done without the risk of breaking a > :>program that currently works. I'm a little puzzled - why would a program issuing an EOV bother to search for "new extents"? If it worked, they've got more space. If it didn't, then they can take other options. VSAM code determines when it needs another extent, and takes care of it automatically - the user doesn't even know that it happened. Extent consolidation only applies to VSAM data sets (see "z/OS DFSMS Using Data Sets"), and it is a huge impact for customers. If extents are adjacent, then they don't run into the limit of 123 extents on a volume. This improves performance, and reduces the likelihood of having to supply additional devices to extend to. Thanks, Mark Thomen Catalog/IDCAMS/VSAM Development ---------------------------------------------------------------------- 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
