On Monday, 06/09/2008 at 04:06 EDT, "Schuh, Richard" <[EMAIL PROTECTED]> wrote: > I would hope that the use of stickers to denote EOT would have gone out > way back in my career.
Reflective stickers went away with the 3480. It introduced a "servo" track that the drive uses to know the position of the tape at all times. EOT is at a certain physical block number, x. Every time. Bigger tape? Then you have a bigger value for x. The tape may be skipping bad data blocks on the tape, but they are at known locations and EOT still occurs at x, so the "effective length" will be less than the "physical length". This is why degaussing today's tape cartridges results in a useless tape: the servo track is destroyed in the process. If you look at the sense data for today's drives, you'll see that it contains tons of block counters AND a [fuzzy] "tape length" indication. Alan Altmark z/VM Development IBM Endicott
