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Data compression not enabled when requested?

Don Lee

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I am copying rebuilt Retro 6 tapes to a disk media set, and have requested data compression in the "options" in the script doing the copy.


The resultant copy works, but the resultant disk media set is larger than expected and the status window in "activities" says data compression is "OFF".


It appears that Retro 9 ( is ignoring my request for data compression

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I just finished a copy of a file media set to a disk set on another volume, and have selected "Data compression (in software)" in the options.


The Summary tab under "Acivities" clearly showed "Compression OFF" throughout the operation, but judging from the size of the resulting backup sets, it was clearly ON.The difference in the sizes is about 28%, which is too large for random format funkiness.

The new (disk) set:


93,743,000,000 (decimal)



The old (file) set:


120,292,000,000 (decimal)


This is at odds with the "107.9 GB" reported in the log file, which is much closer to the "111 GB" reported for the file under the old (obsolete, retrograde, reactionary) "power of two" counting system pre-10.6.


It looks to me like this is a cosmetic problem with the display, not a problem with the compression not happening when requested.


Log from the copy op below. Note that there is no "compression advantage XX%" message:


+  Executing copy-compress at 4/30/12 (Activity Thread 2)
   To Backup Set test-compress...
   -  4/30/12 2:18:17 PM: Transferring from iCompute12d-v9
   4/30/12 5:16:12 PM: Execution completed successfully
   Completed: 652539 files, 107.9 GB
   Performance: 631.1 MB/minute
   Duration: 02:57:54 (00:02:50 idle/loading/preparing)
   -  4/30/12 5:16:12 PM: Verifying test-compress
   4/30/12 5:42:06 PM: Execution completed successfully
   Completed: 652539 files, 107.9 GB
   Performance: 4,587.3 MB/minute
   Duration: 00:25:54 (00:01:48 idle/loading/preparing)

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