From: Frank McConnell <fmc_at_reanimators.org>
Date: Wed Jul 22 14:54:44 1998

Christian Fandt <cfandt_at_servtech.com> wrote:
> DC600 carts are the _physical_ media on which data is stored. I wasn't
> saying DC600 is a format nor was QICxx a format HP uses (never knew what
> protocol HP used 'til you mentioned HCD a bit later in yr msg.)

Yes, the physical carts seem to be the same -- it's easy enough to
scribble over the HCD formatting with a QIC format, at which point the
tape is no longer usable in an HCD drive.

So far as I know the HCD formatting must be written at the factory, and
the tapes I've seen have had either HP or 3M labels on them.

HP also seems to put down its own higher-level format on the tapes
that it sells. Here's a story:

Once upon a time the purchasing agent found she could save a few bucks
ordering the 3M flavor of the tapes, and so we got one for testing.
Well...on the 3000, the software for manipulating these things treats
them as serial discs (which is exactly as wacky as it sounds, the tape
drive is a CS/80 device and so the tapes are addressed by block), and
so you're supposed to use the VINIT tool to format the "disc" and
"serialize" it (i.e. write a volume label that says "this is a serial
disc" for auto-volume recognition to read later). So what I noticed
in my tests was that the 3M tape, when new, took 15 minutes for the
FORMAT step, vs. the HP tapes which took seconds. I suspect that the
time was taken by the tape drive formatting the tape and writing out
the canonical CS/80 stuff like bad-block sparing tables and so forth,
and that HP does this at their factory.

-Frank McConnell
Received on Wed Jul 22 1998 - 14:54:44 BST

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