Bruce, I don't want to go up against you in a DASD knowledge battle (I know I would lose), but my copy of "IBM 3390 Direct Access Storage Reference Summary", GX26-4577-2, August 1990, Table 2 (3390 mode), page 10, says that 255 to 288 byte blocks with keys of 1-22 bytes are max 45 to the track (not 46), so wouldn't the formula be 44+(45*n) as was mentioned in a prior reply?
Peter -----Original Message----- From: Bruce Black [mailto:[EMAIL PROTECTED] Sent: Monday, May 14, 2007 11:58 AM To: [email protected] Subject: Re: Top 10 software install gripes > > Why should directory blocks for PDSes be multiple of 45 ? Thats not entirely accurate. A 3390 track holds 46 directory records, but allocating only 45 allows the EOF for the directory to be placed on the same track. But for additional directory space, use multiples of 46, formula 45+(46*n). That will put 46 on each track, and only 45 on the LAST track, again putting the EOF at the end of that track. Why do this? No particular reason except that it is neater; the first member can start with record 1 on the track following the directory. PDS directory searches don't ever reach the EOF; the last block has a key of all FFs, which stops the keyed search. This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. ---------------------------------------------------------------------- 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
