I'm trying to extract data from DLT tapes. The format is proprietary but we're using a blocksize of 512kb (524288 bytes) and a maximum of 40000 blocks per tape. This works fine on the HP-UX system that wrote the tapes but on my linux-box I get a input/output error when trying to read past 39720 blocks.
The system is running ubuntu breezy with the default 2.6.12 kernel. I've tried two different DLT drives, a Quantum DLT4000 and a HP VS80, same problem on both. Scsi cards tested are both from adaptec, 2944 and 3940 I think.

So question: is there a limit in the kernel somewhere that prevents me from reading past the 39720:th block (19.39Gb) or is there something else that's biting me here?