To set the block size for a SCSI tape device on a Linux system, you can use the mt command with the -f option and the bs parameter.
For example, to set the block size to 64KB for the SCSI tape device /dev/st0, you can use the following command:
mt -f /dev/st0 bs=65536
This will set the block size to 64KB for the specified SCSI tape device.
You can also use the -r option to specify the block size in terms of the number of records. For example, to set the block size to 64KB in terms of the number of records, you can use the following command:
mt -f /dev/st0 bs=1k count=64
This will set the block size to 64KB by specifying the record size as 1KB and the number of records as 64.
Keep in mind that you will need to have root privileges (or be a member of the sudo group) in order to set the block size for a SCSI tape device.
You can use the mt -f /dev/st0 status command to check the current block size for the SCSI tape device.