Thanks Bfitzmai for your answering. I had cleaned the tape drive.
I am using a hp dds-2 tape, 4 mm, compressed capacity: 8GB, that was written in a DDS-2 tape drive of Sun (Solaris 5.5)and "tar cvf /dev/rmt/1n" for some files.
Now, I want to read it in a DDS-3 tape drive of Sun (Solaris 5.8) and...