>From: Sean Witham <Sean.Witham@asa.co.uk>
>On Fri, 21 Mar 1997, Max Bell wrote:
>> [commentary on reasoning behind rewinding device as default omitted]
>
>A dat drive will auto rewind when you hit eject so that doesn't apply.
>(Well it does on the DDS drives I have used)
>Note it may be useful to store a tape at the end of a file ready for
>a new file to be added next time it is inserted. Though I don't think
>this can be done with DDS dat drives anyway.

Yes, but old QIC and TK50 (aka DECtape) drives have manual ejects and
will manage the tape and drive if you try to force an unwound tape to
eject.  It is also possible to unmount unwound 9-track tapes.  I am
unaware of any tape media that is designed to be unmounted unless it
is rewound.  One can easily return to the end of the used portion of
a tape (assuming it and its device drive are not brain-damaged) by use
of the "eom" command to `mt`.

>nrst0 seems the the better choice to me.

Since the "State of the Art" (ha) DLT format uses the same manual eject
mechanism as the old TK50s and both the drive and the tapes are quite
costly, I do not agree.  If you know what you're doing, just set the
TAPE environment variable.

>> The problems you are encountering are due to two factors: (1) You need to
>> tell `dump` that it is dumping to a device as big or bigger than the size
>> of the filesystem involved so it doesn't think it needs to change "tapes".
>> To do this, play with the "d"ensity and "s"ize options.  Beware that due to
>> its age (over 20 years) it cannot really cope with the real numbers, so you
>> will need to understate the density and overstate the size of the "tape".
>
>Use the -B option to set the tape size in KB this option is relatively
>new in dump.

Yes, and hence does not exist on numerous unix flavors.  It is unwise to
depend on non-portable options when alternatives (even odd ones) exist.

Max