OT: DDS Tapes

From: Eric Smith <eric_at_brouhaha.com>
Date: Sun Apr 30 01:44:38 2000

> A DDS1 tape should work in a DDS2 drive, but DDS3 and forward wont!
> I purchased a bunch of 120m tapes for my DDS2 drive, and used them
> for quite a while before discovering I was storing LESS information
> on them than the 90m DDS2 tapes... Grrr...
> If the drive works, stick to the 60m and 90m tapes :)

If you have a DDS2 drive, 120m tapes are the right ones to use. If your
DDS2 drive isn't working correctly with them, it is broken.

Perhaps you meant that 125m tapes (DDS3) don't work right in a DDS2
drive, which is quite true.

Note that both 120m DDS2 tapes and 125m DDS3 tapes can actually be
the same length:

                 ECMA Marketing Specified Native Capacity
Generation Standard "Length" Length Capacity (2:1 compression)
-------------- -------- ---------- ------ -------- -----------------
DDS and DDS/DC 139 60m 3-60.5m 1.3G 2.6G
                  150,170 90m 3-92m 2G 4G

DDS2 198 120m 10-125m 4G 8G

DDS3 236 125m 10-125m 12G 24G

DDS4 288 150m 10-155m 20G 40G

Shorter tape lengths have been made for OEMs, but typically only tapes
with lengths close to the specified upper limits have been available
for retail sale.

If you have a DDS(m) drive, do NOT use DDS(n) tapes for n>m. The oxide
formulations are different, which will prevent data from being reliably
stored. Also the tapes are thinner, and the earlier transports do not use
tensioning aprorpiate for the later tapes. Newer drives are designed with
the requirements for older generation tape in mind, so the older tapes can
be used (at their normal storage density).
Received on Sun Apr 30 2000 - 01:44:38 BST

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