[Info-vax] TLZ7

[Michael Kraemer]

In article <iaugng$18n5$1 at ns.felk.cvut.cz>, smithfarm <presnypreklad at gmail.com>
writes:
> > 2GB uncompressed makes it a TLZ04, DDS-1. TLZ07 does 4GB uncompressed
> > and is DDS-2. Some inconsistency here, not sure who to believe. The
> > hardware is usually definitive.
> 
> Is the only way to tell DDS1 from DDS2 (definitively, from the hardware) 
> to attempt to write more than 2GB to a DDS2 tape and see what happens? 
> Or is there another way?

What puzzles me is the date "December 13, 1985"
which is definitely much earlier than DDS-2 technology.
If it really is a TLZ07, i.e. a DDS-2 drive,
it will only take DDS-2 and DDS-1 media, no DDS-3 and above.
It's not only tape length, but also write density.
The higher capacity media have thinner tapes 
(probably to fit them into the same cartridge size),
and so may even be torn apart when used in an older drive.
Modern drives have media recognition and will spit out
"wrong" tapes.