On Thu, Nov 18, 2004 at 12:14:41AM -0500, Michael J. Pawlowsky wrote:
> 
> >
> >It should be clearer in the docs that use of the tapetype program
> >(now amtapetype) is only of value if you are using software rather
> >than hardware compression (you should not use both although on
> >newer drives it doesn't hurt as it once did).
> >
> 
> Snip snip snip...
> 
> I actually ran amtapetype both with hw compression and without it.
> Total of 25 hours run time!  :-)
> 
> The results are about the same.
> 
> define tapetype DLTIV {
>     comment "by tapetype prog (hardware compression on)"
>     length 17304 mbytes
>     filemark 0 kbytes
>     speed 1259 kps
> }

Had you posted this report without the comment "hw comp on",
about 94 people would have recognized it as run incorrectly,
i.e. with hw compression on.  All but a few of the most recent
tape formats and compressors cause EXPANSION of random data
instead of compressing it.  The nominal observed amount of
expansion is about 10-15 percent, which this fits perfectly.

> define tapetype DLTIV-NoComp {
>     comment "by tapetype prog (hardware compression off)"
>     length 19503 mbytes
>     filemark 0 kbytes
>     speed 1406 kps
> }

And, as usual, the vendor claimed native capacity seems to be
about 2-5% greater than the actual observed capacity.

> 
> I would have thought amanda would have simply asked me to insert a new 
> tape when it reached the end. But it looks like it just aborted. 
> Actually it did nothing for a REALLY long time.. and then finally aborted.

It will; if you configure it to pretend you are a manual changer
and then tell it it is allowed to use more than one tape per run.

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
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