Mark, Bruce Black has given an excellent explanation (as usually does) of the facts about DFDSS and FDR backup tapes, you could also add HSM and a few others(block size in the label is not what written on the tape). The Opentech Systems TapeCopy product can copy and stack these tapes because TapeCopy uses EXCP code to copy tapes block for block. The copy will have the same number and size as the original, block for block.
Check out TapeCopy via the following link; http://www.opentechsystems.com/tape-copy.php Don Don Bolton Director Technical Services 800-460-3011 Phone 469-635-1500 Phone 469-635-1507 Fax www.OpentechSystems.com -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Bruce Black Sent: Wednesday, June 20, 2007 10:14 AM To: [email protected] Subject: Re: Virtual Tape ??? > > John, I guess my complaint/argument is that IEBGENER is an IBM standard > tape copy utility. Data on a tape is sequential (PS), regardless if put there by > another IBM utility like IEBCOPY, IEBGENER, etc. I'm sure I've used GENER > in the past to copy RECFM=U files? The reason that DFSMSdss backup datasets are unique is that the tape label says RECFM=U,BLKSIZE=32760. However, the actual data blocks are as large as 64K. When IEBGENER and similar copy utilities copy the backup, they believe the tape label. All the data blocks are truncated at 32760, so half the data is lost. The DFSMSdss COPYDUMP utility is smart enough to copy the entire block. The same consideration applies to FDR backups, where the real blocksize can be up to 57K. The FDRTCOPY utility must be used to copy FDR backups. The reason for both of these is that they were originally written long before the system supported large blocks. The largest blocksize you could specify at OPEN was 32760. So both products open the backup with RECFM=U,BLKSIZE=32760 and then wrote a larger physical block. This IEBGENER limitation would apply to any RECFM=U dataset where the physical block can exceed the apparently BLKSIZE, but DSS and FDR backups are the only two cases I know of. -- Bruce A. Black Senior Software Developer for FDR Innovation Data Processing 973-890-7300 personal: [EMAIL PROTECTED] sales info: [EMAIL PROTECTED] tech support: [EMAIL PROTECTED] web: www.innovationdp.fdr.com ---------------------------------------------------------------------- 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 ---------------------------------------------------------------------- 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
