<<Does anyone have any information comparing speed and capacity of the HP
DDS drives?
 
Specifically, C1520B using software compression vs. C1530B.  The HP rep
made his biennial visit and said something about the 1520 doing 2 GB/hour
and the 1530 doing 4 GB/hour. Capacities?>>
 
When I installed a 1530 in place of the 1520 two weeks ago, our daily
backup went from 2.3 hours/1.2 tapes to 50 minutes/1 not-full tape. This
is with 90m 2GB tapes.
 
The physical data-transfer rate of DDS drives is 11MB/min. Multiply by
the effective overall compression factor to get the data throughput. HP's
manual for the 1520 series shows "Up to 11 MB/min" for the Model 2000,
"Up to 44 MB/Min" for the 2000DC, which has hardware compression. The
1530 (aka "HP6400 Model 4000DC") manual says "Up to 30MB/min".
 
Capacity is simply the capacity of the media (1.3, 2, or 4 GB) times the
overall compression factor.
 
Steve Dirickson         WestWin Consulting
(360) 598-6111  [log in to unmask]