"Hunkeler Peter , KIUK 3" <[EMAIL PROTECTED]> wrote in message news:<[EMAIL PROTECTED]>.... > Sorry for the incomplete post. I had a finger check... >
> > DREF was introduced when real storage still was a scarce resource but > when > systems already had quite some expanded storage. DREF storage was > pageable > storage but it could only be paged to expanded storage and never to > aux storage. Thus a page fault could be resolved without doing I/O and > could be done synchroneously (a page move). This allowed code running > in disbled state to relieve some fixed storage by using DREF instead. > > > >Of course like FIXED area, after first reference DREF pages will be > fixed > >there unless released or swapped out (for private area). > > No, its pageable storage. > > Since z/OS does not support expanded storage, DREF is much like fixed. > (I do not know the difference in its handling, if any, off hand). > > -- It is interesting to see, how the view on system performance/efficiency changes when the cost of hardware changes: DB2 V8 (iirc) introduced the option to permanently FIX its buffers in order to avoid the overhead of constantly FIXing and RELEASEing them. Tradeoffs between Memory cost and CPU consumption are apparently shifting. Kees. ********************************************************************** For information, services and offers, please visit our web site: http://www.klm.com. This e-mail and any attachment may contain confidential and privileged material intended for the addressee only. If you are not the addressee, you are notified that no part of the e-mail or any attachment may be disclosed, copied or distributed, and that any other action related to this e-mail or attachment is strictly prohibited, and may be unlawful. If you have received this e-mail by error, please notify the sender immediately by return e-mail, and delete this message. Koninklijke Luchtvaart Maatschappij NV (KLM), its subsidiaries and/or its employees shall not be liable for the incorrect or incomplete transmission of this e-mail or any attachments, nor responsible for any delay in receipt. Koninklijke Luchtvaart Maatschappij N.V. (also known as KLM Royal Dutch Airlines) is registered in Amstelveen, The Netherlands, with registered number 33014286 ********************************************************************** ---------------------------------------------------------------------- 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
