Multiple dumps to /dev/nrst8 fail

[Ian Domville]

mcrware!kim at uunet.uu.net (Kim Kempf) writes:
>I'm having a problem with cartridge tape dumps that used to work on SunOS
>3.5 and now doesn't on SunOS 4.0.  The following:
>
>	dump 6ucf /dev/nrst8 /dev/rxy0e
>	dump 6ucf /dev/nrst8 /dev/rxy0f
>
>all dumps fine with no reported problems.  restore will only work on the
>first file saved.  Attempts to restore the other files on the tape (with
>'restore is 2') will fail with the vague message:
>
>	Tape read error: Error 0
>
>Anyone else note such behaviour or am I just doing something wrong?

A few weeks ago, I sent out a similar request on Sun-spots. I received
back several very helpful replies, and I now have a solution to the
problem.

I actually had two problems.  The  first was to do  with tape length.
SunOS 4.0 was supposed to handle tape length correctly. In practice, I had
to specify 575' for a 600' tape. Other people on this site had the same
problem. One reply told me it appeared to vary from make to make. (I was
using 3M cartridges.)

The second was the same as Kim's.  The cause  is that the  new dump
program puts an extra EOF at the end of each file. Consequently, you must
restore files 1, 3, 5, ... to avoid the extra EOFs.

One reply suggested an alternative of dumping the first, rewinding,  mt
fsf 1, dump the second, etc. This gets rid of the extra EOFs,  but sounded
too much like hard work to me.

- Ian Domville

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-Ian Domville (id at stl  ...!mcvax!ukc!stl!id  +44-279-29531 x 2576)