dump under Ultrix 4.1 (DS3100/TK50)

[Mike Black]

In article <2020 at godzilla.tcs.com> jac at zabriskie.berkeley.edu (Gordon Jacobs) writes:
>I just upgraded to Ultrix 4.1 on a DECstation 3100 and when I 
>went to perform a tape backup to TK50, I typed:
>
>	% dump 0u /usr
>
>as usual.  The dump program announced that it would write 10.3
>tapes of the 300Mb partition!  This was based on 1600bpi density
>and when I read the man page, it said that the default was 1600.
>I quit and re-ran the dump using the "d" option to specify 6250bpi
>and the results were more reasonable.  I thought the TK50 had a
>fixed density.  The default under Ultrix 3.1 was such that no 
>density needed to be specified.  Is the dump message just wrong?
>Will it always use the correct density, or what should be specified?
>
>Thanks,
>Gordie Jacobs
> 
I believe that 'dump' assumes it's working with a 9-track.  Seeing as how
the tk50 is a 22 track recorder at 6667bpi you need to fool it some like
this:
dump 0uds 6660 1466 /usr
The 1466 is a correction to 600 feet of TK50 tape at 6667bpi/22track versus
6250bpi/9track.  I've just started doing this myself so no results are
guaranteed, but it should also work well with 'rdump' too.
Maybe someone else can shed some more light.
Mike...


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