I don't know the answer. It may be in a Redbook. I would think that the starting point for any disk search is a track+cylinder location. These have become irrelevant or insignificant with virtual/raid devices.
-----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] Behalf Of Tom Marchant Sent: 12 May 2007 00:47 To: [email protected] Subject: Re: Top 10 software install gripes On Sat, 12 May 2007 00:20:41 +0100, Tony wrote: >Think of where CKD devices came from. Search for a "record" on a disk that >had a record key equal to or greater than the one you are looking for. In >this case the key is the member name. Hardware feature, promoted heavily and >used by JES and DB2 (got that bit from a class 15+ years ago) but not so >sure now. Yes, Search key High or Equal is used for PDS directrory search. And the search will complete with the last used directory block, whose key is eight bytes of x'FF'. The key to a directory block other than the last is thelast member name in that block. That doesn't explain why you'd want the directory to be allocated in full tracks, though. -- Tom Marchant > >-----Original Message----- >From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] >Behalf Of Tom Marchant >> >>I'm not sure how many PDS directory blocks will fit on a track, but I don't >>see >>why it's important either. IIRC, the remainder of the last directory track >>will >>be used for data. In any case, I see no reason to make the directory larger >>just to make it fill the last track. ---------------------------------------------------------------------- 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 No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.467 / Virus Database: 269.6.8/797 - Release Date: 10/05/2007 17:10 No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.5.467 / Virus Database: 269.6.8/797 - Release Date: 10/05/2007 17:10 ---------------------------------------------------------------------- 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
