Tandberg Data Streamer SLR140 External Grey 6722 6883 00 사용자 설명서
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6722 6883 00
SLR140 Features
D:\SLR140 Features for Reliability and
Performance.doc
Performance.doc
Page 8 of 13
Printed: 30.03.04
15:17
8. SLR Features for High Performance
SLR7-140`s In-line Data Compression
Tandberg Data is using a specially designed circuit/ASIC to allow compression of data “on the fly”
before the data is entered into the buffer. This allows the whole buffer to be used for intermediate
storage of the compressed data before written to the tape media. Using this method called In-line
compression; SLR7/60/75/100/140 can buffer twice as much data from the host vs. if a Look-aside
method is used - assuming the same buffer size. This increases overall performance of the tape drive.
before the data is entered into the buffer. This allows the whole buffer to be used for intermediate
storage of the compressed data before written to the tape media. Using this method called In-line
compression; SLR7/60/75/100/140 can buffer twice as much data from the host vs. if a Look-aside
method is used - assuming the same buffer size. This increases overall performance of the tape drive.
In-line compression
The data is compressed in a separate data-compression-chip before entered in the buffer. Thus 100%
of the buffer can be used for intermittent storage of compressed data before written to the media, which
gives higher transfer rate.
The in-line compression method also gives another advantage – better ability to increase capacity and
transfer rate for highly compressible data -, as no additional operation is needed to compress the data.
Bench marks shows that the SLR7-140 can increase the transfer rate – and capacity – up to more than
six times the native transfer rate and capacity when writing highly compressible data.
transfer rate for highly compressible data -, as no additional operation is needed to compress the data.
Bench marks shows that the SLR7-140 can increase the transfer rate – and capacity – up to more than
six times the native transfer rate and capacity when writing highly compressible data.
Other technologies uses half of the buffer for the “raw” uncompressed data transfer the data to a
compression chip, compress the data, and enter the compressed data to the other half of the buffer.
This means both reduction of the buffer capacity, and need of additional operations for the tape drive’s
processor.
compression chip, compress the data, and enter the compressed data to the other half of the buffer.
This means both reduction of the buffer capacity, and need of additional operations for the tape drive’s
processor.
Other technologies’ Look-aside Compression
The buffer is divided into two sections: Compressed and non-compressed that reduces the effective
buffer size significantly
SCSI
Contr.
Comp-
ression
ression
Buffer
Tape
Host
Compressed
data only!
SCSI
Contr.
Comp-
ression
ression
Tape
Host
Buffer
Compressed data
Uncompressed data