On Thu, 1 Aug 2013 18:30:46 -0500, Paul Gilmartin wrote: >PSA makes z/OS partly reentrant. Exploited by multiple CPUs in any >LPAR, but not, AFAIK, by VM or PR/SM.
Huh? What do you mean by "partly reentrant"? PSA is 8K bytes at real address 0 in memory that allows each processor to operate independently. It is made possible by the prefix register, which provides the mechanism that maps the first 8K of real storage to a different 8K range of absolute storage. In particular, this allows interrupts to occur on each processor without interfering with each other. I don't know whether VM or PR/SM use the prefix register, but I would assume that they do. Do you have reason to think otherwise? -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
