22 Mar
2003
22 Mar
'03
2:35 p.m.
Gunther Schadow wrote:
so I sorted through my last weekend's bait, hooked
up my new HSZ40
(with 50 GB in 4 StorageWorks boxes plus all sorts of tape drives,
TSZ07, TLZ07, TZ68, and ~88) to my PC for FreeBSD. It's so much
fun to read a 9-track reel from a FreeBSD PC (just too bad it doesn't
have a transparent top cover to show off the reels).
I have bulk-erased a bunch of TK50 tapes in the hopes that they
would work as DLT III and IV tapes as well, but these drives
still went into write-protect mode. Does anyone here know details
about the DLT media? I mean it is a well-known fact (and I proved
it to myself many times) that CompacTape I works just fine as
CompacTape II. So why not as III and IV? Is it really the tape
or might it be some notches on the cassette that are used to
code the kind of tape?
The problem is I didn't get any tape media for my nice DLT tape drives
and this stuff is so darn expensive if bought new. Any ideas?
Jerome Fine replies:
Memorex used to have a list of all of the physical characteristics
of CompacTape / DLT tapes. I can't remember any of the actual
numbers, but I do remember the key information you require.
CompacTape I and CompacTape II were completely identical
in every detail - except for for the colour of the name on the case.
Usually The "CompacTape" label was brown; the "CompacTape II"
was usually blue. Oh yes, DEC charged a fair bit more for the tape
with the blue label. Both the TK50 and the TK70 used these tapes.
However, once a given drive started to write on a blank tape, it was
not possible to switch the tape to be written by the other drive. In
particular, the TK70 could read tapes written by a TK50 drive, but
the TK70 would immediately WRITE PROTECT itself as soon as
the tape was interested into the TK70. A bulk erase is required to
allow switching the tapes between the TK50 and the TK70 - as
your have already discovered.
As for the DLT III media, the physical characteristics were substantially
different from the CompacTape media. I am quite sure that the drives
which use the DLT media are unable to use the CompacTape media.
Likewise, the TK50 / TK70 drives are unable to use the DLT media.
DLT IV media are very different again from DLT III media.
Sincerely yours,
Jerome Fine
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