Transfer Rates; Data Compression; Speeds - HP Ultrium Drive Technical Reference Manual

10 Performance specification

Transfer rates

Sustained transfer rate
Burst transfer rate
ATS data rate range (3:1)
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:
Compression Engine Bandwidth:
Maximum Streaming Compression Ratio:
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

Maximum tape speed
Tape read/write speed
Tape rewind speed
Native: 80 MB/s
Compressed (2:1): 160 MB/s
Ultra3 SCSI wide: 320 MB/s
Ultra3 FC:
120 MB/s
3:1
7.00 m/s
5.32 m/s (Ultrium-3), 5.50 m/s (Ultrium-1/2)
7.00 m/s
SCSI FC
80 MB/s
160 MB/s
2 GB/s: class 3
27–80 MB/s (U3)
10–30 MB/s (U2)
6.6–20 MB/s (U1)
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