QuickSpecs

DDS Technology Within the tape market there is a wide range of tape technologies, the question for SMB
customers is which one to choose. The answer is clear - DDS/DAT continues to be the unit
volume leader in the tape drive market for small and medium businesses with a current installed
base of over 6 million units and over 17 million DAT drives shipped since its introduction in 1989.
This remarkable tape technology continues to flourish because it meets the needs of the SMB
market for cost-effective, reliable backup better than any other technology available. Of the 1.4
million backup tape drives shipped in 2006, IDC estimates that approximately 40% were DAT
drives.
Unlike AIT, VXA, ADR, SLR, DLT and SDLT, DDS/DAT is based on an open standard format for
data interchange. The influential DAT manufacturers group presides over this open standard with
verification processes that ensure compliance. With multiple manufacturers developing and
shipping DDS/DAT products, customers benefit from increased competition, which leads to better
prices, faster development and more choice.
DDS format for DAT is a helical scan format where data is written diagonally across the width of
the tape. The advantage is that, by allowing subsequent tracks to have different writing angles and
to overlap, a much greater capacity can be achieved for a given length of tape because no guard
bands are necessary. The data format also allows for fast location of tracks and data. To achieve
this, the rotating drum is tilted at a slight angle (6°) from the vertical. The drum has four heads
(two write heads and two read heads), located at 90° intervals. For each rotation of the drum, two
tracks are written. The read heads verify the data that has been written (recorded) and the drive
rewrites if necessary. The open format ensures interchangeability between different DDS format
drives.
HP has been involved in the design and development of DAT drives since the beginning and
applies these many years of experience to its current line of DAT products. Not only does an
investment in DAT technology provide the security of a format with a history of outstanding
reliability, the legacy of backward compatibility also provides the potential for future expansion
without compromising your investment in the technology.
The target market for DAT continues to be direct-attach backup. In small and medium sized
businesses cost of ownership, ease of use and a proven history (i.e. low risk) are paramount. DAT
technology provides the capacity and performance needed in a tape backup solution for
workstations and entry-level servers.
Specific Note on DAT 160
The DAT 160 drive employs the same technology as previous DAT products, and uses DAT 160
wide media in order to achieve higher capacities. However, it maintains the 2 generation backward
compatibility promise and can still read and write data to DAT 72 and DAT 40 (DDS-4) cartridges.
It does this by recognizing the different tapes (wider DAT 160 and the narrower DAT 72/DDS-4).
QuickSpecs
HP StorageWorks DAT Drives
Product Highlights
DA - 11883 Worldwide QuickSpecs — Version 28 — 1.26.2008 Page 7