Gentle HP3000 List Members,

Last year, HP released the DDS-4 tape technology.  I suspect many of you
may be looking at this as a follow on to DDS-3.  Here is some information
to factor in your planning.

Enhancements:
The DDS-4 technology is an outgrowth of the current DDS technology.  By
using a more compact write and a longer tape, DDS-4 promises to be able to
hold up to 40GB per cartridge.  The track pitch is now 6.8 micron as
opposed to 9.1micron on DDS-3.  The tape, DDS-4, is now 150 meters.  It is
also thinner at 5.9 micron.  The transfer rate has been increased due to
many factors, to 3MB/s native.  HP advertises 6 MB/s with compression.
 Sony advertises only 4.8MB/s with compression.  BTW, the capacity and
rates have now surpassed DLT4000 technology.

Backward compatibility.
The DDS-4 tape will only get the capacity and the rates detailed above
using DDS-4 150 meter tapes.  A DDS-4 drive will be able to read and write
on DDS-3 125 meter tapes and DDS-2 120 meter tapes.  It will only be able
to read, not write on DDS-1 90 meter tapes.  DDS 60 meter tapes cannot be
read from or written to by a DDS-4 drive.

Forward compatibility.
As you can imagine a DDS-3 or earlier drive will not be able to read a
DDS-4 150 meter tape.  I do not believe that it could write on one either
and since the tape is thinner, putting one of those in a DDS-3 or 2 or 1
would not be "a good thing."

HP and others have promised tighter controls on the device to further
prevent the "drifting" that has been experienced with earlier DDS
technology.


Kind regards,

Denys. . .

Denys Beauchemin
HICOMP
(800) 323-8863  (281) 288-7438         Fax: (281) 355-6879
denys at hicomp.com                             www.hicomp.com