[Info-vax] TLZ7

[John Wallace]

On Nov 4, 6:00 pm, smithfarm <presnyprek... at gmail.com> wrote:
> > What puzzles me is the date "December 13, 1985"
> > which is definitely much earlier than DDS-2 technology.
>
> Well, it actually says "Q.C. PASSED 85.12.13". Since YY-MM-DD is quite
> common in Asia, where I assume this was made, I interpreted it as
> "December 13, 1985". But you are right - according to Wikipedia DDS-1
> came out in 1989.
>
> > 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.
>
> I read somewhere that there is a jumper setting (on the real TLZ07) that
> turns media recognition on and off.
>
> To be sure, I will not use DDS-3 media in it, but it was interesting
> that it worked at all. I will writing a longer file to a DDS-2 tape and
> see what happens.
>
> I don't have any DDS-1 tapes yet to try. I shopped around and it looks
> like they cost about $4 here and, since I guess nobody uses them
> anymore, there is a 2-week lead time between ordering and delivery.
>
> In the meantime, I found the autoloader cartridge. It was on the bottom
> of a box of tapes that came with the drive. The loader takes 4 tapes.
>
> Nathan

I may have been confusing TLZ04 (1.3GB) with TLZ06 (2GB). The Tru64
docs have some handy tables re media and format compatibility;
highlights below are from
http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/V40G_HTML/MAN/MAN7/0087____.HTM

  __________________________________________________________
  Media Type	 Drive Type
  __________________________________________________________
  DDS-1 (60m)	 TLZ04, TLZ06, TLZ07, TLZ09, TLZ10,
		 SDT-7000, SDT-9000, SDT-10000
  DDS-1 (90m)	 TLZ06, TLZ07, TLZ09, TLZ10,
		 SDT-7000, SDT-9000, SDT-10000
  DDS-2 (120m)	 TLZ07, TLZ09, TLZ10,
		 SDT-7000, SDT-9000, SDT-10000
  DDS-3 (125m)	 TLZ10, SDT-9000, SDT-10000
  DDS-4 (150m)	 SDT-10000

Or to put it another way:

TLZ04 is 1.3GB, on 60m DDS-1, no compression.
TLZ06 is 2.0GB on 90m DDS-1, or nominal 4.0GB compressed.
TLZ07 is 4.0GB on 120m DDS-2, or nominal 8.0GB compressed.

Take the cover off the unit and find out what's really inside. Afaik,
only a handful of companies made DAT drives, and DEC weren't one of
them. Identifying the real vendor may lead you to vendor documentation
which in turn may tell you Important Things e.g. what those buttons
do.

I did some work with a professional studio kit supplier (part of the
empire that invented, and was the biggest manufacturer of, DAT) and
they didn't like to use DAT for studio masters due to its unacceptably
high probability of mangling the only copy of a studio master tape.
Most folk weren't so fussed - who cares if you lose an occasional
backup tape. DLTs were the ones to go for if what you wanted was day
in day out reliability, but in a different league for cost.

If you were to actually post (rather than loosely describe) the
console and VMS output, someone may be able to comment on whether the
"bunch of MKA (TAPE) and JKA (CHNGR) devices" is expected or (perhaps
equally possible) is the result of some SCSI misconfiguration
somewhere which will need fixing before this will work right.

Someone else will have to suggest where to find MRU.

Have a lot of fun.