The HP DAT40 drives have dip switches to turn off hardware compression.
If you have one of the external drives you need to open the case in order to
get to the dip switches at the bottom of the drive...

You can find the description in the manual or online from
http://www.hp.com/products1/storage/products/tapebackup/dds_dat_drives/dds4_
dat40/index.html

Bernhard



> -----Original Message-----
> From: owner-amanda-users AT amanda DOT org
> [mailto:owner-amanda-users AT amanda DOT org]On Behalf Of Ronan KERYELL
> Sent: Monday, November 25, 2002 8:56 AM
> To: amanda-users AT amanda DOT org
> Subject: DAT DDS4 size or avoiding hardware compression on Linux/Debian
>
>
> I'm in trouble with a HP SureStore DAT40 (DDS-4) since I cannot write
> compressed partition past 16GB instead of achieving the theoretical 20GB.
>
> I guess it is because the drive is in hardware compression mode, but I do
> not know how to explain it to the drive... :-)
>
> I've read the man st and is does not look as clear as on Solaris...
>
> gaudi:~# ls -al /dev/nst0*
> crw-rw----    1 root     tape       9, 128 Mar 14  2002 /dev/nst0
> crw-rw----    1 root     tape       9, 224 Mar 14  2002 /dev/nst0a
> crw-rw----    1 root     tape       9, 160 Mar 14  2002 /dev/nst0l
> crw-rw----    1 root     tape       9, 192 Mar 14  2002 /dev/nst0m
>
> I've tried each /dev/nst0* without success :
>
> gaudi:~# tapetype -f /dev/nst0
> wrote 524508 32Kb blocks in 1604 files in 9324 seconds (short write)
> wrote 505626 32Kb blocks in 3102 files in 11965 seconds (short write)
> define tapetype unknown-tapetype {
>     comment "just produced by tapetype program"
>     length 17021 mbytes
>     filemark 403 kbytes
>     speed 1576 kps
> }
> gaudi:~# tapetype -f /dev/nst0a
> tapetype: could not rewind /dev/nst0a: No such device or address
> gaudi:~# tapetype -f /dev/nst0l
> tapetype: could not rewind /dev/nst0l: No such device or address
> gaudi:~# tapetype -f /dev/nst0m
> tapetype: could not rewind /dev/nst0m: No such device or address
>
> Hmmm... Strange...
>
> Any help in the audience ? :-)
> Thank you,
> --
>     Ronan KERYELL              |\/
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>