On Sat, 30 Sep 2006, Guennadi Liakhovetski wrote: > On Thu, 28 Sep 2006, Kai Makisara wrote: > > > Both 1 and 2 are needed for 1 MB block size. max_sectors_kb for tapes is > > not visible in /sys. > > Kai, as st maintainer, you surely know - on my tape HP C1533A I cannot > seem to set up any block size other than 1 byte... Is it __really__ 1 byte > or is it just some fixed block size that the drive doesn't report and > cannot change? And it means I cannot test setting of different block > sizes? I have a (unconnected ATM) slightly newer C1555D, wonder if that > could use different block sizes?... > This is interesting. I also have HP C1533A (firmware 9608) and I have not had any problems with setting the block size. Dmesg shows that the drive supports blocks up to 1<<24 - 1 bytes: st0: Block limits 1 - 16777215 bytes. I just tested with kernel 2.6.18 that setting block size works in my system. > 1 byte I see in "mt status" and setting anything else with "mt setblk" > causes "st0: Incorrect block size." > This message comes from reading in fixed block mode when the drive tries to read a block and the size of the block does not match the block size set to the drive. If you have written the tape with block size 1, you can't read it with any other block size in fixed block mode. If you are testing the limits of the LLD, it may be easier to use variable block mode. What matters is the size of the SCSI i/o and in this case you know it exactly. In fixed block mode the i/o size may be several blocks unless you are careful. -- Kai - To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
