Bruce, This seems strange. We have had a couple of clients that have verified it made a very big and noticable improvement when they turned off this option with CopyCat. And CopyCat is simply doing OPEN TYPE=J after increasing the file-sequence number for the next volume, and the allocation of course has RETAIN coded on it. Not sure if this is also device related. What type of device were you using? My last response from IBM indicates that if the volume supports MSNS(?) it will be used to verify the volume mounts; if the drive does not support MSNS then the previous data sets trailer labels are read to compare the label data to data saved in the UCB Tape Class extension (which was saved during CLOSE processing of the previous file). So, if the device you tested on did not support MSNS, it would only re-read the previous tape labels (if my understanding of the email from IBM was correct).
The clients that have reported the largest performance hits have been 3590 users, but they also stack a lot more data compared to 3490/E drives. Russell Witt CA -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] Behalf Of Bruce Black Sent: Thursday, October 12, 2006 10:34 AM To: [email protected] Subject: Re: Moving data from old cartridges (3490) to new ones (3590) > Russ, do you have any idea if this affects programs like FDRABR and > COPYCAT which create multiple files in the same program execution? > The text refers to passed and RETAINed tapes, but it is not clear > about multiple OPENs. We have the default of YES, so I GTF traced a multiple file create on an A/S tape. There is no rewind and read of VOL1 between files. So this apparently only affects tapes that are actually passed to another step. In any case, it seems that it should be set to NO if all of the systems sharing the A/S tape are OS/390 2.10 or z/OS, in which case they all use the current A/S sharing protocol and the problem of a foreign tape being mounted are nil -- ...<snip>... ---------------------------------------------------------------------- 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
