User`s guide

Chapter 5 Theory
Recording Method
LTO-3 Half-Height Tape Drive User’s Guide 46
Recording Method
The LTO-3 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-3 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 SCSI at 160 Mbytes/sec.
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-3 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.