backup to 150-MB cartridge tape

[Grenville Whelan - Sun UK]

In article <8624 at brazos.Rice.edu> cerveza!gary at sunkist.west.sun.com (Gary Cattelino) writes:
>X-Sun-Spots-Digest: Volume 9, Issue 202, message 4
>
>In the discussion they say to use 590 to handle media errors (600 feet
>minus 10 feet to handle media flaws).  Well, I just looked at a DC6150 and
>it says 620 feet.  Maybe the proper size to use for these tapes is 610
>feet?  It also says the density is 1200, not 1250 from the previous
>posting.  Which is correct?  I've been using 1200 with no problems.  Maybe
>a density of 1250 will allow me to store more on one tape?
>
>Anyone know the answers to these questions?

For QIC cartridges, I don't use the "-c" option on dump, but calculate all
parameters as follows :-

Density for QIC always 1000bpi
Tape Length is real length * number of tracks * 0.9 to leviate 10% for errors,

Therefore, for a 60Meg (QIC24/9TRK) tape, density is 1000bpi, and length
is (600 * 9 * 0.9), = 4860.

	eg. dump 0usfd 4860 /dev/rst8 1000 /dev/sd....

For a 150Meg (QIC150/24TRK) tape, density is 1000bpi, and length is
(600 * 24 * 0.9), = 12960.

	eg. dump 0usfd 12960 /dev/rst8 1000 /dev/sd...

Hope this helps,
Grenville

 Grenville Whelan, Sun UK, Hilton House, Lord St, Stockport, Cheshire, SK1 3ND
                   [Tel. +44 061-477-3100, Email: gwhelan at sunuk.Sun.COM]

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