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
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