DDS Technology
DDS Technology
DDS Technology
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 and over
15 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 3.5 million backup tape drives shipped in 2003, Gartner
Dataquest estimates that approximately 50% 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
straightness with which the track is written to tape is referred to as the linearity of the track and is critical
in ensuring the data is always recoverable.
HP has been involved in the design and development of DDS drives since the beginning and applies
these many years of experience to its current line of DDS products. Not only does an investment in DDS
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 DDS/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. DDS
technology provides the capacity and performance needed in a tape backup solution for workstations
and entry-level servers.
QuickSpecs
HP StorageWorks DAT Drives
HP StorageWorks DAT Drives
HP StorageWorks DAT Drives
HP StorageWorks DAT Drives
Product Highlights
DA - 11883 Worldwide — Version 15 — March 20, 2006
Page 6
