Tandberg Data Streamer SLR140 XE Kit SCSI Internal Grey 6721693400 사용자 설명서
제품 코드
6721693400
SLR140 Features
D:\SLR140 Features for Reliability and
Performance.doc
Performance.doc
Page 12 of 13
Printed: 30.03.04
15:17
Writes four data channels simultaneously which gives higher transfer rate and
improved reliability (see the Improved ECC section for more information).
improved reliability (see the Improved ECC section for more information).
Advanced Data Coding VR
2
TM
In previous generations of linear tape drives, a peak detection algorithm was used to read back the data.
To be able to secure the distinction between neighbors bits it was necessary to put in “dummy” bits
after every second real bit. 1,7 RLL - Peak Detection Read Channel is commonly used in linear
recording.
For detection of each peak independently, every 2 data bits are recorded as 3 bit-cells on the tape
To be able to secure the distinction between neighbors bits it was necessary to put in “dummy” bits
after every second real bit. 1,7 RLL - Peak Detection Read Channel is commonly used in linear
recording.
For detection of each peak independently, every 2 data bits are recorded as 3 bit-cells on the tape
Conventional 1,7 RLL coding- max 67% coding efficiency
With the PRML technique the bits can overlap and still the algorithm will be able to retrieve the
original content. In addition more bits can be coded into each signal transition on the tape. This enables
a higher logical bit density and transfer rate although the physical density remains the same.
original content. In addition more bits can be coded into each signal transition on the tape. This enables
a higher logical bit density and transfer rate although the physical density remains the same.
Tandberg Data is using the VR
2
(Variable Rate Randomizer) algorithm patented by Overland Data in
the SLR7-140 products. SLR is the first linear tape drive in the market utilizing PRML (and VR
2
)
encoding.
The VR
2
writing technology is more area efficient, and will thus help assure future
higher capacity and higher performance SLR tape drives.
SLR60 -140 Head
Write channels
Read channels
SLR140 W/R
Four data channels and
one servo channel
SLR50 Write
(+SLR32, SLR24 read)
Two data channels and
one servo channel
Forward Reverse
Reverse Forward
OVERHEAD
10000101001001…………....x
technology improves on these inefficiencies - approaching 99% coding efficiency
OVERHEAD
1 0 x 0 0 x 0 1 x 0 1 x 0 0 x 1 0 x 0 1