mt-st fails on DDS-3 cartridge with StorageWorks DAT72 under Linux 2.6.20

[Etienne LURQUIN]

Hi,

My drives works fine with DDS-4 cartridges but I still have several DDS-3 cartridges that I would like to use for incremental backups but mt-st fails on most operations (except status, rewind and eject) with the followings in syslog:
st0: Current: sense key: Medium Error
kernel: Additional sense: Sequential positioning error
kernel: Info fld=0x2
kernel: st0: Error on write filemark.

mt-st -f /dev/nst0 status gives the following:
SCSI 2 tape drive:
File number=0, block number=0, partition=0.
Tape block size 0 bytes. Density code 0x25 (DDS-3).
Soft error count since last status=0
General status bits on (41010000):
BOT ONLINE IM_REP_EN

I tried using dd as well for a test write but it ended up with an i/o error. The doc of the drive says DDS-3 cartridges are supported.

Anyone any idea ?