Embedded Diagnostics; Error Checking; Buffer; Compression - Overland Data DLT LibraryXpress Series Service Manual

Embedded Diagnostics

The DLT LibraryXpress System and each of its modules provide three levels of embedded
diagnostics. The Power-On Self Test (POST) performs various verification tests on the
system's configuration and host interface and device control functions, as well as memory
tests, at power-up. The second level of diagnostics is the User Diagnostics, which provide for
displaying and changing configuration options. The third level, CE Diagnostics, include
advanced diagnostics to be used by Customer Engineers for servicing the LibraryXpress
System. Both the User Diagnostics and the CE Diagnostics may be selected from the front
panel.
User Diagnostics are described in greater detail in Chapter 2 - Installation. CE Diagnostics
are described in Chapter 4 - Maintenance and Chapter 5 - Troubleshooting.

Error Checking

All drive models used in the DLT LibraryXpress System apply a 16-bit parity check to each
record, a 64-bit CRC to each 4 kB of data, and Reed-Solomon error correction code overall.
In addition, there is an internal parity check on the data buffer.

Buffer

Drives of the 2000XT, and 4000 series are equipped with a 2 MB data buffer, while 7000
series are equipped with a 4-MB data buffer.

Compression

All drive models used in the DLT LibraryXpress System use the standard Digital Lempel-Ziv
(DLZ) data compression algorithm.

Capacity

A single Base Module with its ten-cartridge magazine offers formatted capacities as shown in
Table 1-1. The data capacities of a Global Control and a Capacity Module are shown in
Table 1-2. The capacity of any module is determined by the series of drive used, as well as the
media type. When DLTtape III or IIIXT cartridges are used with 4000 or 7000 series drives,
capacities are limited accordingly.
MODEL
LXB2X10
LXB4X10
LXB7X10
10
Table 1-1 Base Module Tape Capacities
CARTRIDGE
DLTtape IIIXT
DLTtape III
DLTtape IV
DLTtape IV
CAPACITY PER FULL MAGAZINE
A
CARTRIDGE COMPRESSED
15 GB
10 GB
20 GB
35 GB
B
300 GB
200 GB
400 GB
700 GB
Chapter 1 - Introduction