Figure 9-4.A cinched tape pack.
stopped. Figure 9-4 shows an example of a cinched tape
pack (note the complete foldover of one tape strand).
Pack slip Pack slip occurs when the tape is
loosely wound on the reel and exposed to excessive
vibration or heat. This causes the tape to shift (side-to-
side), causing steps in the tape pack. When a tape reel
with pack slip is used, the magnetic tape will unwind
unevenly and rub against the sides of the tape reel of
the tape units tape guides. This can damage the tape
and cause oxide shedding on the edges of the tape.
Figure 9-5 shows an example of pack slip.
Spoking Spoking occurs when a magnetic
tape is wound onto the tape reel with the tension
increasing toward the end of the winding. The higher
tension on the outside of the tape pack causes the inner
pack to buckle and deform. Spoking is also caused by
the uneven pressures created when the tape is wound
on a distorted hub, or when the tape is wound over a
small particle deposited in the reel. Figure 9-6 shows a
spoked tape pack.
Windowing Windows are voids or see-
through air gaps in the tape windings. They happen
when the magnetic tape is loosely wound onto a tape
Figure 9-5.A tape with pack slip.
Figure 9-6.A spoked tape pack.
reel, and especially when the loosely wound reel is
later exposed to extreme heat or humidity. Figure 9-7
shows a windowed tape pack.
DATA STORAGE ON MAGNETIC TAPE
Storage of data using magnetic tape units is based
on the following principles: