Quantum DLT 2000 Handbook page 27

adjacent tracks. This data recording technique is called Symmetric
™
Phase Recording (SPR). SPR's herringbone pattern eliminates the
need for guard bands and thus allows greater track density.
Figures 2-5 and 2-6 show the arrangement of read/write elements on
the two-channel DLT 4000 heads and the four-channel DLT 7000 and
DLT 8000 heads. When reading DLTtape cartridges recorded on earlier
models, the DLT 7000 and DLT 8000 read/write heads automatically
shift to a vertical orientation. This feature provides backward compati-
bility and protects the end user's investment in the DLTtape system.
Figure 2-7 shows the read-write head assembly for the Super DLTtape
drive. Super DLTtape drives incorporate newly designed Magneto-
Resistive Cluster (MRC) heads. This design features clusters of very
small, cost-effective magneto resistive tape heads, densely packed in a
small area on the head. MRC heads deliver higher data transfer rates
and greater data density than traditional heads of similar size. They are
also less susceptible to negative effects due to environmental (tempera-
ture and humidity) conditions.
Simpler Tape Path
The design of the head guide assembly (HGA) is at the heart of what
makes DLTtape technology superior (see Figure 2-8). More than any
other characteristic, it is what makes a DLTtape drive a DLTtape drive.
It is a patented design, and it is one of the keys to the success of the
DLTtape system.
The head guide assembly positions the tape in front of the self-
calibrating read/write heads. The DLTtape system HGA is different
from competing technologies. On 4mm and 8mm helical scan sys-
tems (see Figure 2-12), the head guide systems are designed to
move. These systems must reach out, hook the tape, wrap it
around the rotating read/write drum, hold it in position, and then
move the tape back into its cassette.(See Figure 2-12.)
2.6 WHAT IS THE DLTtape SYSTEM?