> -----Original Message-----
> From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On
> Behalf Of Paul Schuster
> Sent: Tuesday, July 24, 2007 12:33 AM
> To: IBM-MAIN@BAMA.UA.EDU
> Subject: Is a page protected?--how to determine
> 
> Hello: I have a need to determine if an address in storage is page
> protected
> in order to determine if a PGSER UNPROTECT needs to be done.
> 
> The best I have tried and seen in earlier posts is to look for a CC=1 on a
> TPROT backed up with an ESTAE.
> 
> Are there any other methods to do this?
> 
> Thank you.
> 
> Paul Schuster

Use a loop with IVSK and TPROT for key 0. Something like this:

       L   R2,page_address
LOOP   BR  0         purge cache
       IVSK  R0,R2   page-in
       TPROT 0(R2),0 test for key zero storability
       BO  LOOP      oops, paged-out. try again
       BNZ PROT      page protected, LAP, read-only data space
       BZ  NO_PROT   not protected

Testing for key zero storability will catch page protection, or
low address protection, or read-only data space. You may want
to provide special filtering for those weird cases.

Jeffrey D. Smith
Principal Product Architect
Farsight Systems Corporation
700 KEN PRATT BLVD. #204-159
LONGMONT, CO 80501-6452
303-774-9381 direct
303-484-6170 FAX
http://www.farsight-systems.com/

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