QuickSpecs

HP StorageWorks DAT Drives

Product Highlights

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.

DA - 11883 Worldwide — Version 15 — March 20, 2006

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HP 40 SCSI manual Product Highlights, DDS Technology