>I have a customer who must prove to a governing agency that they are
>adequately tracking media life.  They are using AIT-3 media which SONY
>says has a lifecycle of 30,000 uses and a shelf life of approximately 30
>years.  So - in order to comply with their regulations, they must show
>that they are tracking the uses.  Does the value in the field called
>Write Pass Number in the volume record equate to what the manufacturer
>considers "uses"?  I believe this to mean a complete write pass from
>beginning to end of media.

The manufacturer equates "uses" to the number of times the tape is loaded
as an average wear indicator: some areas of the tape may, of course, be
passed by the heads and rollers much more than others.
I would advise against trying to track usage from an application (TSM)
unless no other means area available, as the information needs to be
permanently associated with the cartridge.  Remember that volume info
within TSM endures only as long as the volume is defined within that
server: if it leaves the collection for any length of time, the historic
information is lost.

Tape manufacturers utilize various means of recording cartridge data.
In the case of AIT, you have the Memory-in-Cassette (MIC) flash memory
chip, which records a lot of information about the cartridge. Quoting Sony:
 "The AIT-3 cartridge features a built-in 64kb flash memory chip that stores
  directory and operational information. The result is rapid access to desired
  data and greatly reduced loading and ejection times. MIC also enables
  proactive management by capturing key indicators like number of times loaded,
  authorized users and corrected error rates. Starting with AIT-3, the chip can
  also be accessed using a non-contact reader for even more operational
  flexibility."
I would strongly advise that you pursue that tracking information.

References:
http://www.mediabysony.com/ctsc/pdf/spec_ait3.pdf
http://www.aittape.com/mic.html