SCSI tape: rst0 or rst8

[Joerg Schilling - H. Berthold AG Berlin]

Hi,

the most importent difference between the QIC-11 (rst0) and the
QIC-24(rst8) format is that the tape controller places a burst at the very
beginning of the tape when the first data is recorded. This burst is
placed between the B.O.T. holes and the load point hole on the tape and
enables intelligent drives - as the Wangtek - to calibrate the position of
the Read/Write Head. This causes a Wangtek drive to use several seconds.
You can hear this - it moves the tape forwards and backwards until the
optimal head position for track 0 is found. Subsequent reads or writes
will use the so found position for track 0.

You should therefore use the QIC-24 format whenever possible to enhance
the interchangeability of the tapes. There will be less/no problems with
tapes comming from/going to drives with missaligned heads.

I think that is the real reason for SUN to change the format of their
installation tapes.

        J. Schilling
        H. Berthold AG
        Teltowkanalstr. 1-4
        D 1000 Berlin 46
        +49 30  7795 - 400

joerg at berthold.de

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