Quantum LTO-9 HH SAS, User Manual

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Chapter 2: Introduction
Speed Matching
Quantum LTO-9 HH SAS User’s Guide 17
Speed Matching
To improve system performance, the drive uses a technique called speed
matching to dynamically adjust its native (uncompressed) data rate to
the slower data rate of a server. With speed matching, the drive
operates at different speeds when reading or writing the Ultrium 7.
Native data rates are as follows in the table below.
Table 2 Performance
Parameters
If the server's net (compressed) data rate is between two of the
preceding native data rates, the drive calculates the appropriate data
rate at which to operate. Speed matching dramatically reduces
backhitch, the condition that occurs when a tape stops, reverses, and
Ultrium Generation Media
Generation 8
Media
Generation 9
Media
Speed matching data
rates (MB/sec)
365.0 408.0
341.0 385
318.0 366
306.4 347
273.0 325
249.5 305
226.0 284
203.0 263
180.0 244
157.5 223
135.0 203
112.0 177