> On 29.12.2015, at 18.59, Emmanuel Florac <eflorac@xxxxxxxxxxxxxx> wrote: > > Le Fri, 25 Dec 2015 17:53:46 +0200 (EET) > Kai Makisara <Kai.Makisara@xxxxxxxxxxx> écrivait: > >> the patch implements the following: if the >> size is 1, the driver tells the drive to use default partitioning for >> two partitions. For the HP Ultrium this should result in partition 0 >> of 1425 GB and 1 of 37.5 GB. I don't know if this is a useful >> addition. > > Oh BTW I didn't check what's happening in code, but actual values > should be 37.5 GB for partition 0 and 1425 GB for partition 1, not the > other way around. > What I quoted is from the HP manual. The driver tells the drive to format the tape according to the default of the drive (i.e., sets the FDP bit in the mode page). The order of partitions is an interesting question. The usual use case is to have a small partition for the index and a large partition for the data. The small partition should positioned so that it can be accessed fast. For the old really linear drives this means the beginning. It was decided that the first partition on the tape was given number one and the second partition had the number zero. The HP LTO seems to use this numbering for the default. The SCSI standard does not specify how the partitions should be numbered. Many drives use physically sequential numbering nowadays. LTO uses wrap-wise partitioning and I don’t think locations of the partitions have any effect on access speed. 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
