The PDSE Usage Redbook seems to suggest that your speculation is correct: The significance of the block size keyword (BLKSIZE) has changed slightly. All PDSEs are stored on disk as fixed 4 KB blocks. These 4 KB physical blocks are also known as pages. The PDSE is logically reblocked to the block size you specify when you open the data set. The block size does not affect how efficiently a PDSE is stored on disk, but it can influence how efficiently the system reads from it and writes to it because it affects the size of the storage buffers allocated for a PDSE. You should allow the DFSMSdfp System-Determined Blocksize function to calculate the best block size for your data set, by not specifying any value for it.
For a 3390 volume, 12 pages (4 KB blocks) fit on one track. Don Imbriale -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Eric Bielefeld Sent: Tuesday, October 03, 2006 11:33 AM To: [email protected] Subject: Re: Default System BLKSIZE for PDSE Does the PDSE blocksize work like the blocksize on a load module? As I understand it, if you allocate a loadlib with 32720, and there is a large enough load module, the 1st block written will be 32720 bytes long. Probably slightly less, as a couple of other small blocks are written first. Then, if I understand correctly, the next block is written out and will fill the track. Does the PDSE work similarly, or is my speculation all wet? *********************************************************************** Bear Stearns is not responsible for any recommendation, solicitation, offer or agreement or any information about any transaction, customer account or account activity contained in this communication. *********************************************************************** ---------------------------------------------------------------------- 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
