Now i get it ...thanks a lot for making this clear to me ..... On Wed, Feb 24, 2016 at 6:23 PM, Vernooij, CP (ITOPT1) - KLM < [email protected]> wrote:
> 'Doesn't the PSA contents change at that point ?' ==> No, each PSA remains > the same. The program's PSA-pointer is just set to the PSA of the processor > it runs on. > > 'as the PSA is no longer the same' ==> there is no 'the PSA' there are > many PSAs. 'The' PSA a program sees, is the PSA of the processor it runs on. > > Kees. > > > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[email protected]] On > Behalf Of baby eklavya > Sent: 24 February, 2016 13:42 > To: [email protected] > Subject: Re: Prefix save area - confused > > Thank you sir ...So , what happens when a program running in address space > A gets dispatched on a different processor B following an interrupt ? > > Doesn't the PSA contents change at that point ? ...Then as a part of > prefixing , the absolute location is mapped to a different block in real > storage . > > This is what i get confused always - as the PSA is no longer the same .... > > On Wed, Feb 24, 2016 at 5:45 PM, Vernooij, CP (ITOPT1) - KLM < > [email protected]> wrote: > > > There is one for each processor, so all address spaces dispatched on the > > same processor will access the same PSA. In that way each PSA is common > for > > all address spaces. > > > > Kees. > > > > -----Original Message----- > > From: IBM Mainframe Discussion List [mailto:[email protected]] On > > Behalf Of baby eklavya > > Sent: 24 February, 2016 12:17 > > To: [email protected] > > Subject: Prefix save area - confused > > > > Hello Listers , > > > > Apologies in advance if this is a dumb question . But every time i read > the > > below paragraph from ABC volumes , i get lost in the middle . > > > > *prefixed storage area* > > > > This area is often referred to as low core. The PSA is a common area of > > virtual storage > > from address zero through 8191 in every address space. There is one > unique > > PSA for > > every processor installed in a system. > > The PSA maps architecturally fixed hardware and software storage > locations > > for the > > processor. Because there is a unique PSA for each processor, from the > view > > of a program > > running on z/OS, the contents of the PSA can change any time the program > is > > dispatched > > on a different processor. This feature is unique to the PSA area, and is > > accomplished > > through a unique DAT manipulation technique called prefixing. > > > > > > In what way do they say PSA is a common area of every address space when > > there is a unique PSA for every processor ? > > > > > > Is there a different place where this concept is documented with more > > details ? .. > > > > Can someone help me understand the above statement ? > > > > Regards, > > Baby > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > ******************************************************** > > For information, services and offers, please visit our web site: > > http://www.klm.com. This e-mail and any attachment may contain > > confidential and privileged material intended for the addressee only. 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