On Sun, 20 Jan 2008 10:07:07 -0600 Paul Gilmartin <[EMAIL PROTECTED]> wrote:
:>On Fri, 18 Jan 2008 20:38:15 -0500, Anne & Lynn Wheeler wrote: :>>A.6.3.1 Bypass Post Routine :>>http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DZ9ZR003/A.6.3.1?SHELF=DZ9ZBK03&DT=20040504121320&CASE= :>>from above: :>>The following routine allows the SVC "POST" as used in MVS/ESA to be :>>bypassed whenever the corresponding WAIT has not yet been executed, :>>provided that the supervisor WAIT and POST routines use COMPARE AND SWAP :>>to manipulate event control blocks (ECBs). :>This is the Principles of Operation; it is not the Assembler Services :>manual. Note carefully the "provided that" clause. It's important. :>Is there any explicit guarantee in the Assembler Services manual :>that "the supervisor WAIT and POST routines use COMPARE AND SWAP :>to manipulate [ECBs]", and that the ECBs are updated only after all :>collateral operations are completed? If not, the programmer who :>engages in such shenanigans is using unsupported interfaces. In the past (370 pre PLO), CS was the only way to do this function. While it certainly is possible for IBM to rewrite WAIT/POST to use the PLO instruction, I certainly doubt that such a code change will occur. The code in the POPs is used - all over the place - to avoid an unnecessary SVC/PC call. It is completely safe to use. -- Binyamin Dissen <[EMAIL PROTECTED]> http://www.dissensoftware.com Director, Dissen Software, Bar & Grill - Israel Should you use the mailblocks package and expect a response from me, you should preauthorize the dissensoftware.com domain. I very rarely bother responding to challenge/response systems, especially those from irresponsible companies. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
