'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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