On Thu, 9 Dec 2010 13:33:30 -0500, Gunter Hochreiter <[email protected]> wrote:
>The 1st 32gig are reserved for JVM then comes 288G-32G for a System >area. Then the user areas What is the System area used for ? Any >ideas ? The system area is used for whatever system functions need it. Nothing we know of had needed it before z/OS R12, though some of the z/OS designers had foreseen a possible need for it someday. As it turned out, both the Restart phase of Checkpoint/Restart processing and the child-side part of UNIX Fork processing examine storage and fail if there is any allocated 64-bit storage when they run, since they can't properly restore the original storage contents. RACF changes in z/OS R12 ended up allocating 64-bit storage early in the life of a job (before the Restart and fork-child processing), and so z/OS needed something like the local system area in order to avoid Restart and Fork failures. Checkpoint/Restart and Fork simply ignore that area, and everything continues to work as it used to. -- Walt Farrell IBM STSM, z/OS Security Design
