I'm going to be horrably pragmatic here and assert that, while it is nice to have a image of the tape (using either dd or Tapeutils: http://www.brouhaha.com/~eric/software/tapeutils), it is more important to have the software on the tape in a useable backup. With the Sun tapes, that means that you can mostly do tar (with the exclusion of the sandalone copy, munix, and miniroot which would need to be dd'd off) and it is better than having the tapes sit around in the garage and fall apart. Tar/cpio created tapes are nice in that the dd'd files can be read with tar -f (or cpio), making them useable as-is. inst-format tapes and wbak/rbak tapes don't have this luxury, so I like to do the extraction to files and "rebinding" into a tardist or disk-file wbak archive so they can be used even if you don't have a tape drive. IOW, both have their uses, but it is infinitely better to have one than to have none.