On Tue, 24 Apr 2012 16:23:50 +0300, Binyamin Dissen wrote: >If the "invalid" page can be paged-in, in what way is it "invalid"?
Bit 53 of a page table entry is the Page-invalid bit. If it is set in the page table entry that is used to reference a location in storage, a Page-translation exception, PIC 11 (commonly known as a "page fault") is recognized. Similarly, bit 58 of the segment table entry is the Segment-invalid bit. If it is set in the segment table that is used to reference the page table needed to reference a location in storage, a Segment-translation exception (PIC 10) is recognized. There are similar "invalid" bits in bit 58 of each of the three levels of region tables. It is more common for these exceptions to be resolved and the instruction retried than it is for the access to result in a S0C4 abend. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: INFO IBM-MAIN
