> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:[EMAIL PROTECTED] On Behalf Of Edward E. Jaffe > Sent: Thursday, September 29, 2005 9:57 AM > To: [email protected] > Subject: Re: Instruction Set Enhancement Idea > > > Binyamin Dissen wrote: > > >Why are more storage keys needed? > > > > > > That's a good question. Right now PSW keys 10-15 are (almost?) never > used for anything. Key 9 is used slightly in a somewhat kludgy manner. > > DOS/VS aka VSE/ESA aka z/VSE gives each "static" partition its own > storage key. This harkens back to the real-memory-only days > when there > was one -- and only one -- address space. That's pretty much just old > baggage any more since the advent of dynamic partitions, which look a > whole lot like MVS address spaces. > > -- > .-----------------------------------------------------------------. > | Edward E. Jaffe | |
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 This message (including any attachments) contains confidential information intended for a specific individual and purpose, and its content is protected by law. If you are not the intended recipient, you should delete this message and are hereby notified that any disclosure, copying, or distribution of this transmission, or taking any action based on it, is strictly prohibited. ---------------------------------------------------------------------- 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
