HP Ultrium Drive - Manual (Page 25)

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10 Performance specification
Transfer rates
The bandwidth of the data compression engine determines the drive’s streaming capabilities
based on the compression ratio of the data it is handling as follows:
The drive will match the throughput of any host up to the maximum native transfer rate
multiplied by the current compression ratio. There will not be any performance penalty for hosts
that are slower than the maximum. This capability is accomplished with a 64 MB buffer and
the Adaptive Tape Speed (ATS) algorithm.
Data compression
The compression engine uses an enhanced algorithm based on ALDC where data expansion
due to redundant data is minimized to <5%. This is achieved by having two compression
schemes (normal and pass-through) with the ability to switch dynamically between them.
It is possible to force the drive to use Scheme 2 (pass-through mode) of the LTO-DC algorithm
using the Data Compression mode page or the SDCA parameter in the Sequential Access
Mode Page.
Speeds
SCSI FC
Sustained transfer rate Native: 80 MB/s 80 MB/s
Compressed (2:1): 160 MB/s 160 MB/s
Burst transfer rate Ultra3 SCSI wide: 320 MB/s
Ultra3 FC: 2 GB/s: class 3
ATS data rate range (3:1) 27–80 MB/s (U3)
10–30 MB/s (U2)
6.6–20 MB/s (U1)
Compression Engine Bandwidth: 120 MB/s
Maximum Streaming Compression Ratio: 3:1
Maximum tape speed 7.00 m/s
Tape read/write speed 5.32 m/s (Ultrium-3), 5.50 m/s (Ultrium-1/2)
Tape rewind speed 7.00 m/s