Thank you for doing a better job of explaining the benefits of the extended storage key feature than I have done so far.
Subordinate to any PSW-key, up to 256 distinct spaces can be defined, each having its own distinct protection. IMHO, it greatest benefit would be in highly multi-tasked/multi-threaded environments. I suspect the z/Linux could make great use of this capability. John P Baker Software Engineer -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of McKown, John Sent: Thursday, September 29, 2005 18:37 To: [email protected] Subject: Re: Instruction Set Enhancement Idea > Binyamin Dissen wrote: > > >Why are more storage keys needed? I can see one possibility. Sort of like an extention to the subspace concept that CICS uses. Allow these "extra" storage keys to be used by an unauthorized program which wants/needs to protect its data areas. Or the PKM field. The program is running in "true" PSW key 8. But it can request that an area be placed into auxillary key "n" to protect against other key 8 users. In order to update the area, the program would need to do something akin to an SPKA to set the PSW auxillary key to non-8. This sort of thing might be useful in a high sub-tasked application. Especially if this sub-tasked application allows for "user code" which might tend to overlay application control blocks. -- John McKown Senior Systems Programmer UICI Insurance Center Information Technology ---------------------------------------------------------------------- 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
