D=Fjah; Overview; Tape Formats; Data Compression - Compaq DLT User Manual

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+D=FJAH

Overview

This chapter provides information on tape formats, data compression, and
system and controller requirements for all Compaq DLT Drives and formats.
For information on tape software, refer to the "readme" card enclosed with the
drive. More information may also be obtained by accessing the Compaq Web
Site on the Internet at http://www. compaq.com.

Tape Formats

The Compaq DLT Drive is a high-capacity, high-performance streaming tape
drive designed for use with Compaq servers. The DLT Drive is a full-height
tape drive with a 5-1/4-inch form factor. The DLT Drive has a multi-channel
read/write head, utilizes a Digital Lempel-Ziv (DLZ) high efficiency data
compression algorithm, and has a filing system to maximize data and
minimize data access time.
The DLT Drive uses a half-inch tape cartridge compatible with the DLT Tape,
DLT Tape II, DLT Tape III, DLT Tape IIIXT and DLT Tape IV..

Data Compression

The DLT Drive reads and writes both uncompressed (native) and DLZ
compressed data. The 15/30 DLT model features a native formatted capacity of
15 gigabytes and a sustained native data transfer rate of 1.25 megabytes per
second (MB/s). The 35/70 DLT model has a native formatted capacity of
35 gigabytes and a sustained native data transfer rate of 5.0 MB/s.
When operating in compressed mode, data capacity is affected by how much
the data can be compressed. Most data can be compressed at an approximate
2:1 ratio. For instance, data compressed at a 2:1 ratio would provide a total
drive capacity of 30 GB for the 15/30 DLT Drive and 70 GB for the 35/70
DLT Drive.
Writer:
Jim Belew
Overview
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Compaq DLT Drive User Guide