>> I'm curious how you might be expecting to factor in IDRC compression with >> the data stored on the tape? I believe that the BLKCNT represents what is >> being stored, not what got sent down the channel. >>
>On tape drives with IDRC or other compression, MVS is only aware of >logical blocks sent across the channel, not the physical representation >on the tape (except very indirectly by indicators of % of media used). >My understanding is that with compression, the compressed logical blocks >are assembled by the tape controller into "super blocks" that are >written on the physical tape, but that structure is not communicated >back to MVS because those are issues that are completely handled at the >tape controller level. > SMF 21 now contains compression information (see APAR OA20077). Regards John ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
