Oh legacy!
1. First set the block size to variable
mt -f /dev/stx setblk 0
2. rewind the tape
mt -f /dev/stx rewind
3. copy the files using input block size =512 (still don't know how to find out the ibs? any idea?)
dd if=/dev/stx of=/myfate ibs=512 count=3 // imagining a file to be occupying 3 blocks of 512 bytes. write a loop to copy all files.