Not knowing the internals, but making some reasonable, I think, assumptions... If you are doing anything other than a full page, or full pages, STORAGE OBTAIN, the system has to put a FQE element in the top of the page, and so it would have to back the first virtual page with a real page. If you are doing full page STORAGE OBTAIN or GETMAIN, then no FQE is needed and I wouldn't expect the page to be backed. It is an interesting question, but does it matter in this day of machines having millions of real pages? Maybe it did back with a 168 and maybe a whole meg or two of real memory.
Chris Blaicher Technical Architect Software Development Syncsort Incorporated 50 Tice Boulevard, Woodcliff Lake, NJ 07677 P: 201-930-8234 | M: 512-627-3803 E: [email protected] -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Tom Marchant Sent: Wednesday, December 02, 2015 9:03 AM To: [email protected] Subject: Re: Is first page always backed by real storage upon return from STORAGE OBTAIN? On Wed, 2 Dec 2015 14:06:28 +0100, Peter Hunkeler wrote: >Allocating 100 MB area, I found that the first page in the newly >allocated area always seems to be backed by real storage upon return >from STORAGE OBTAIN. Do you specify BNDRY=PAGE? Are you using z/OS 1.9 rules or z/OS 1.10 rules? How were you able to determine this? LRA perhaps? Why do you care? >Is this true? I don't know; maybe Jim or Peter will have an answer. >Where is this documented? I wouldn't expect that it is. -- Tom Marchant ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ________________________________ ATTENTION: ----- The information contained in this message (including any files transmitted with this message) may contain proprietary, trade secret or other confidential and/or legally privileged information. Any pricing information contained in this message or in any files transmitted with this message is always confidential and cannot be shared with any third parties without prior written approval from Syncsort. This message is intended to be read only by the individual or entity to whom it is addressed or by their designee. If the reader of this message is not the intended recipient, you are on notice that any use, disclosure, copying or distribution of this message, in any form, is strictly prohibited. If you have received this message in error, please immediately notify the sender and/or Syncsort and destroy all copies of this message in your possession, custody or control. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
