Hillary Corney wrote:
>
> Hi ftapers,
>
> I got on this list when trying to get a Ditto Max to work with ftape. I
> never did get it going properly so. I replaced it with an IDE 8G HP
> Colorado Tracker and on a separate machine a digital TLZ -09 DB SCSI-2
> Dat both of which which work fine - But I cannot store anything near what
> I believe to be the proper capacity of the tapes on either drive.
>
> I think that this is because I have no idea how to set the Block size,
> densitiy and compression properly. I have read the man pages for mt and
> dump and tar I just dont know what settings I should use to get optimum
> performance out of these tape drives.
>
> I have tried tar and dump.
>
> Please could somebody explain how I should set the Block size density and
> compression on these drives and what the proper command syntax is.
Hillary -
Setting the block size MAY have an effect on the capacity of the drive,
but keep the following in mind:
The HP IDE drive does NO hardware compression. So, unless you are using
software compression, you will get 4GB per tape - period. Also, it is a
fixed block (512 bytes) drive.
The DDS-2 drive (TLZ-09) is actually an Archive/Conner/Seagate Python
drive. It does perform hardware compression. Using a 120M tape, you
should get around 6.5GB per tape (2:1 is a myth!). Using a 90M tape
will net you around 3.2GB. To get these values, set the block size to
variable with mt:
'mt -f /dev/nst0 setblk 0'
Good luck,
Tim
Tim
