10Performance Specification; Transfer Rates; Data Compression; Speeds - HP LTO-4 Technical Reference Manual

10 Performance specification

Transfer rates

Full-height drives
Maximum transfer rate
Streaming native 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
Encryption engine bandwidth
The drive will match the throughput of any host up to the maximum native transfer rate multiplied by
the current compression ratio. There is no performance penalty for hosts that are slower than the
maximum. This capability is accomplished with a 128 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:
Compressed (2:1):
7.00 m/s
6.20 m/s (LTO 4)
5.32 m/s (LTO 3)
6.20 m/s (LTO 2)
7.00 m/s
HP LTO Ultrium 4 drives technical reference manual, volume 4: specifications
HP restricted
120 MB/s
240 MB/s
40–120 MB/s (LTO 4)
27–80 MB/s (LTO 3)
13.7–35.6 MB/s (LTO 2)
360 MB/s
360 MB/s
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