Quantum DLT 2000 Handbook page 126

Figure 11-3 Typical Helical Scan Tape System
pull tape out of the cartridge and around a spinning read/write
head. Acute wrap angles and recording-side contact reduce
tape life.
and records to the end. The drive then steps the head to the next
track, reverses direction and records back to the beginning of the
tape, and so on. One of the main reasons DLTtape drives achieve
such high data transfer rates is because data is written using multiple
channels. DLT 4000 systems use two channels, DLT 7000 and
DLT 8000 drives use four, while Super DLTtape drives use eight.
This Parallel Channel Architecture (PCA) gives DLTtape technology
a major advantage over competing single channel systems in both
speed and accuracy. Not only do multiple channels enable faster
throughput, but they allow bad data blocks to be rewritten to an
alternate channel. This fault-tolerance enhances data accuracy by
allowing bad blocks to be rewritten on the next available channel.
Along with its channel-independent data scheme, DLTtape systems
use multiple error detection and correction techniques to ensure
11.4
DLTtape SYSTEM TECHNOLOGY COMPARED
must