On Fri, Jun 02, 2006 at 06:32:58PM +0100, Chris Lee wrote:
> Just to add to the whole tape type thing :)
> I ran amtapetype on my DLT8000 (40/80GB) using a DLTIV tape.
> Now I assumed that it should give me a 40GB capacity as I have hardware 
> compression off.
> But I get the following:
> define tapetype DLT8000 {
>     comment "just produced by tapetype prog (hardware compression off)"
>     length 36650 mbytes
>     filemark 0 kbytes
>     speed 3944 kps
> }
> 
> Now it is not far off but should it not be closer?
> Also I get a lot of shoe shining during amtapetype run
> 
> Chris.
> 
> Jon LaBadie wrote:

...

You could have deleted the unrelated message.

At first inspection, a 9% difference from expected,
I'd guess HW compression was on.  But you say no.  OK.

I think, but am not certain, lots of shoe shining can
also reduce apparent capacity.

Shoe shining generally is too slow feeding of the data
or lots of tape files.  I think at the end of each file,
the drive stops, backs up and resyncs to start the
next file.

My chart says a DLT-8000 should do about 6MB/sec,
you are only doing 4.  Maybe it is a feed problem.

Another possibility is you failed to give amtapetype
an estimate of the tape size.  Amtapetype wants to write
approximately 100 files to the tape and uses the estimate
to size the files accordingly.  If you gave no estimate
then it uses a default small size that is most appropriate
to low capacity tape drives.

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
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 Princeton, NJ  08540-4322      (609) 683-7220 (fax)