Chapter 4 Theory
Recording Method
LTO-4 (Model B) Half-Height Tape Drive User’s Guide
37
Recording Method
The LTO-4 (Model B) Half-Height Tape Drive records data using write-
equalized (0,13/11) Run Length Limited (RLL) code. RLL (0,13/11) Data
bits are defined as follows:
•
ONE
is represented by a flux transition at the center of a bit-cell.
•
ZERO
is represented by no flux transition in the bit-cell.
Data Buffer
In its default configuration, the LTO-4 (Model B) Half-Height Tape Drive
has a 128-Mbyte buffer. The buffer controller has a burst transfer rate of
320 Mbytes/sec., and utilizes bank switching to achieve a maximum
average bandwidth of nearly 240 Mbytes/sec. The high bandwidth is
needed to support look-aside data compression in the case of
compressible data being transferred from the SCSI.
Data Integrity
The mechanical and electrical design of the drive ensures that drive
performance does not degrade over time. Changes in head alignment,
head wear, component drift, and other factors are minimized to ensure
that data integrity and interchange capability are not compromised. The
drive also incorporates adaptive Finite Impulse Response (FIR) filters that
modify the equalization of each read channel dynamically to
compensate for many of those changes.
The error rate of the LTO-4 (Model B) Half-Height Tape Drive is less than
1 hard error in 10
17
bits. The undetectable error rate is 1 in 10
27
bits
read.
Summary of Contents for LTO-4 (Model B)
Page 6: ...Contents vi LTO 4 Model B Half Height Tape Drive User s Guide Index 81...
Page 8: ...Figures viii LTO 4 Model B Half Height Tape Drive User s Guide...
Page 10: ...Tables x LTO 4 Model B Half Height Tape Drive User s Guide...
Page 20: ...Chapter 1 Introduction Features 4 LTO 4 Model B Half Height Tape Drive User s Guide...
Page 92: ...76 LTO 4 Model B Half Height Tape Drive User s Guide...