The 64 kiB blocksize is to maximize throughput and avoid "shoe shining".
mt -f /dev/nst0 setblk 64k
tar -c -v -R -b128 -f /dev/nst0 test_dir
returns:
bloc 0 : test_dir/
bloc 1 : test_dir/file_1.bin
bloc 204802 : test_dir/file_2.bin
bloc 2252803 : test_dir/file_3.bin
bloc 4300804 : test_dir/file_4.bin
...
But the block number in the tar
output corresponds in 512 B blocksize, despite blocking factor giving 64 kiB blocksize (128 * 512).
And then, regardless of blocksize of the mt command (variable, 64 kiB).
The goal would to random access in the Tar-tape. Convert 64 kiB blocksize to 512 implies to trim.
Is there a way to matching records size of tar
and mt
?
st
command (more detailed asmt
) : italic_Many programs (e.g.,tar(1)
) allow the user to specify the blocking factor on the command line. Note that this determines the physical block size on tape only in variable-block mode._italicmt -f /dev/nst0 setblk 0
. Viewed on forum : italic_tar/dd/whatever blocksize != (SCSI) tape device driver block _italic ([linuxmisc.com/14-unix-administering/b290ded6513059e2.htm])