Dump parameters for Exabyte

[Russ Poffenberger]

In article <1990Jul31.030327.13409 at rice.edu> matt at oddjob.uchicago.edu (Matt Crawford) writes:
>
>|I have conducted tests on 106m consumer 8mm videotapes.  They work okay in
>|Exabyte drives, but you can only fit 1.075 gigabytes onto them.  Two
>|gigabytes is the MAXIMUM tape size the drive will take, but 112 meters is
>|apparently not the largest size of tape available.
>
>This can't be true.  Every week we dump fourteen partitions to a single
>tape, and the sum of the sizes is shown in the "used" column of df's
>output to be 1230727 kB.  Looking at the tape, measuring the radii of the
>hub, the unused portion, and the whole tape, it seems that 2/3 of the
>tape's length was used.
>
>We dump to a local tape with blocks of 100.  Maybe that acocunts for the
>difference somehow, although I don't quite see how.

Keep in mind that EACH file (partition, whatever you want to call it) on
an Exabyte tape requires 2Mbytes for the EOF marker. Therefore, if you
dump 14 partitions, expect to use 28Mbytes more than you thought.

Russ Poffenberger               DOMAIN: poffen at sj.ate.slb.com
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