Example Decoded Log Page Dump - SCSI Tape

The results below were run under Windows XP using a HP 36 GB SCSI Disk.

C>\scratch>smartmon-ux -Cx \\.\TAPE0

SMARTMon-UX [Release 1.41, Build  1-NOV-2009] - Copyright 2001-2009 SANtools(R), Inc. http://www.SANtools.com

Discovered TANDBERG SLR7 S/N "SN007005396" on \\.\TAPE0 (tape) [Bus/Port/ID.LUN=0/3/12.0]

Statistical log pages dump below [# of bytes reserved for value in device]:

 Total logical data blocks transferred: 7248

 Total physical blocks written to media: 55023104

 Total physical blocks read from media (Read and Space operations only): 101376

 Approx remaining capacity of partition 0 (in KBytes): 19690708

 Approx remaining capacity of current partition (in KBytes): 19690708

 Approx maximum capacity of partition 0 (in KBytes): 19690708

 Approx maximum capacity of current partition (in KBytes): 19690708

 Number of file marks: 9

 Number of set marks: 0

 Number of minutes of motion since last head cleaning: 94

 Number of head cleanings: 5

 Total power-on minutes: 360949

 Total number of cartridge loads: 146

 Number of servo lock retries: 0

 Number of servo track seeks: 0

 Number of lost servo locks on writes: 0

 Number of write servo dropouts: 0

 Number of lost servo locks on reads: 0

 Number of read servo dropouts: 0

 Current selected track number: 0

 Cartridge serial number: 496256  

 Number of times this cartridge loaded: 18

 Number of beginning-of-tape markers passed for this tape: 253

 Number of end-of-tape markers passed for this tape: 14

 Number of cartridge write past counters: 27

 Number of minutes cartridge has been in motion: 121

 Write compression ratio (percentage - reset on cartridge change): 168

 Read compression ratio (percentage - reset on cartridge change): 0

 Percentage of data with compression between .89 and 1.2 - reset on cartridge change: 0

 Percentage of data with compression between 1.2 and 1.6 - reset on cartridge change: 28

 Percentage of data with compression between 1.6 and 2.2 - reset on cartridge change: 71

 Percentage of data with compression between 2.2 and 3.6 - reset on cartridge change: 0

 Percentage of data with compression greater than 3.6 - reset on cartridge change: 0

 Buffer under-runs: 22

 Buffer over-runs: 1

 Write errors corrected with possible delays: 155808

 Total Write errors: 345

 Write errors corrected: 345

 Times correction algorithm processed (on Writes): 0

 Bytes processed (on Writes): 295436288

 Unrecovered errors (on Writes): 0

 Read errors corrected with possible delays: 0

 Total Read errors: 1

 Read errors corrected: 1

 Times correction algorithm processed (on Reads): 1

 Bytes processed (on Reads): 7602176

 Unrecovered errors (on Reads): 0

Program Ended.

The log pages provide a great deal of insight when dealing with tape and autochangers. Consider how valuable the highlighted fields are when dealing with software vs. hardware compression; data integrity; tape rotation; and so on. The buffer under-runs tells us that that tape drive couldn't keep up with the data stream, and buffer under-runs tells us how many times the host couldn't keep up with the tape.