small question about tape-based dumps

[Jerry McAllister]

On Sat, Oct 17, 2009 at 06:49:02PM -0600, Tim Judd wrote:

> On 10/17/09, Jerry McAllister <jerrymc at msu.edu> wrote:
> <snip>
> 
> > You do not need to. dump alrady writes that when it finishes each time.
> > If you to that, you will get a second one at that location.
> >
> > You do not need to do the rewind and mt fsf between each dump.  I just
> > do it to make it very clear to myself in my scripts what I am expecting
> > and that I am doing it right.
> >
> > ////jerry
> 
> <snip>
> 
> If dump is the tool for tapes, and tar is named after tape archives...
> 
> Do both of these utilities write the *proper* EOF to whatever medium
> it's writing to?
> 
> I bring this up, because dump can also write to a file on a formatted
> FS.  Does the file end with this same EOF?  What does tar do?

EOF means something completely different on a file system than it does
on a tape.

So, yes, the system knows where the file ends on both, but it is
done differently.

////jerry


> 
> Why have a mt weof function if it's useless?  I'm loosing the logic in
> this one, trying to make sure things work as they should.  I admit
> tapes on bsd are so foreign to me, I might as well be speaking
> $another-language.

It is not useless.  It just isn't necessary in that situation.
Remember, mt(1) is used on more than just dumps.

////jerry


> 
> 
> Please help.