On 9 November 2011 08:30, Rob Scott <[email protected]> wrote:
> My own reference list for key assignments : > > 0 Supervisor > 1 JES > 2 Reserved* (used to be VSPC) > 3 Reserved* > 4 Reserved* > 5 Data management (eg DFP) > 6 VTAM and TCAM > 7 IMS, DB2 and MQ > 8 Problem state programs > 9 CICS user > 10-15 n/a > > Note that (*) for "reserved" does not mean that you will find no users of > storage in these keys. > > In is very common for system software products (from IBM and ISVs) to run > with a non-problem state storage protect key and it is better for the > integrity of the system if they choose a key that is *not* key0 if at all > possible to avoid unintentional overlays of supervisor control blocks. I have > not seen too much key3 usage in the past, but have often come across key2 and > key4 being used by products. > > You should be able to spot the main users of "interesting" keys by entries in > the SCHEDxx member of PARMLIB. On older hardware consoles it was easy to configure a display of CPU activity by key. On really old hardware (370/168 and the like), one could turn a knob to one of 17 positions, and see total usage, or that for each PSW key, on an analogue meter. On some newer machines it is possible to arrange various bar graphs to the same effect, though they lack the instant gratification of the knob and jumping meter. Tony H. ---------------------------------------------------------------------- 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
