Jim Rankin wrote:
>
> --- Tim Jones <[EMAIL PROTECTED]> wrote:
> > Well, that's going a bit far. The problem with the
> > Max/TR-3 issue is
> > one of head assembly. Some time, the laws of
> > manufacturing and physics
> > prohibit carrying forward old technology. In order
> > to create a head
> > assembly that can place 90+ tracks on a piece of
> > tape that is .318"
> > wide, the physical magnet pieces have to be so small
> > that they could not
> > possibly write a track wide enough to be recognized
> > by a TR-3 capable
> > head. Plus, the magnetic properties of the new,
> > thinner media makes the
> > electronic model much different between drive types.
> >
>
> That sounds reasonable for some cases, but Ditto does
> read/write their own smaller tapes (down to 3 GB) with
> the Ditto Max. This makes me wonder what the obstacle
> is for any of the manufacturers doing this with
> similar 10 GB drives. I'd be happy to switch to a
> Travan 10 GB, or even 8 or 5 GB drive if it would
> read/write the TR-3 as well, as Ditto does with the 3
> GB Ditto tapes. But the newer Colorado drives will
> only read the TR-3.
Again, it's a technology issue. They can't write TR-3 because the
required track width is TOO LARGE for the heads in the Max (and other
high capacity) drives. Also, remember that even though the drives can
READ the older tapes, this doesn't mean that you could write a TR-3 with
ftape drivers and then read it in the TR-4 with the standard ATAPI or
SCSI drivers. The logical format of the tapes is quite different. This
is permissible under DOS/WIN because their software is dedicated to its
task, and not generic in nature like bru | tar | cpio | et al. Under
Unix (and Linux) the app software depends upon a standardized driver
layer to process read and write requests. Under DOS/WIN, the
applications generally have dedicated drivers that can operate in
whatever manner the vendor deems appropriate.
> I'd even be willing to reformat the TR-3's in a newer
> drive first, if that would work, but I can't find any
> claim that it does work. Incidentally, I've found that
> reformatting often reduces error rates over factory
> formatting anyway, so I'd be totally unwilling to buy
> a drive with no format capability.
The Ditto Max formatted tapes are quite different from TR-1/2/3 and
other QIC-80/120 class tapes. One other tidbit I've picked up in the
difference between TR-3 and Max media -- the Oersted values of the media
layer are dramatically different. In order to keep the tracks tight
enough on the Max, the heads write a much weaker magnetic signal. In
fact, a Max head probably wouldn't even make a magnetic dent on a
non-Max tape.
> Thanks for your considerable info on all this!
You're quite welcome. Hopefully, it's also helping others in their tape
drive selection decisions.
>
> Jim
>
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--
Tim Jones [EMAIL PROTECTED]
Vice President http://www.estinc.com/
Enhanced Software Technologies, Inc. (602) 470-1115
"The BRU Guys"
