>  The TU58 was never intended as a backup or production medium.  It
>was designed to replace the TU55/TU56 as a small file-structured
>random access device.  That's right, I said random access.  "But wait,
>tapes are sequentially accessed..."  Yes.  But TU58 tapes (and TU55/56
>tapes) have blocks with block numbers which can be accessed randomly
>like a disk.
>
>  Anyway, that's the strength of those tapes that they wanted to
>protect...not the actual encoding format.

Well the TU55/TU56 DECtapes were certainly used as backup or production
media, disks were too small to be any use then so permanent storage was
intended to be on tape.  TSS/8 had a command to zero your account when
you logged out, I'm sure it wasn't unique.

The shame is that TU58s are such a poor replacement for TU56s.  They're
slower *and* have less capacity, plus the hardware can't format the tapes
and the format's copyrighted so you can't buy those weird Scotch clone
DECtapes or anything for the TU58.  And unless I totally misunderstand
it, the QIC-80 format is block-replaceable too...

John Wilson
D Bit