Loading and Unloading Tapes
When you are loading or unloading (mounting or
dismounting) a magnetic tape, look for tapes with
irregular windings and reel warpage. You will see that
as tape is wound on a reel, it is normal for some of its
edges to protrude slightly. These irregularities usually
result from high-speed rewinding. The terrific speed at
which tape moves during a high-speed rewind produces
the slightly irregular winding caused by air being
trapped between adjacent layers of tape. This, in itself,
will not cause improper operation of the tape, but it does
require you to use good judgment and extreme care
when handling tapes.
MOUNTING A TAPE.— When you mount a tape,
make sure the tape unit is not being used for another job.
Check to make sure you are mounting the correct reel of
tape according to job requirements. Tapes have external
labels that identify the data or programs on them.
Remember, if the reel of tape is an input, be sure the file
protection ring is removed. If the tape is an output, be
sure a file protection ring is inserted. Then proceed to
mount the tape. Have one of the more senior operators
on the system show you how to perform this operation
because mounting a tape and depressing the proper
keys/buttons differ from one system to another.
Basically, you will place the reel on a hub and lock the
reel in place.
Then you thread the tape through the
read/write head assembly onto the machine take-up reel
(unless the tape unit is a self-loading tape unit). Once
the tape is properly loaded, the ready light comes on.
If the tape is not properly seated on the tape unit’s
hub during use, it will wobble or appear to be warped. If
the file protection ring is not completely inserted, this,
too, can produce the same effect. In either case, the reel
behaves like it is warped, and upon rewinding, the edges
of the tape can become badly damaged.
Self-Loading Tapes.— The use of self-loading
tapes makes tape loading much easier. Self-loading
tape units eliminate the need for you to manually thread
a tape between the read/write head assembly onto the
machine take-up reel. All you need to do is to mount
(place) the reel of input or output tape on the file reel hub
and allow a small strip of tape to extend from the reel
(anywhere from 2 to 6 inches, depending on the type of
tape unit). Then, by depressing the proper control panel
keys/buttons in the appropriate sequence, the tape unit
automatically threads the tape by using a vacuum to pull
the tape into the vacuum column past the read/write
head assembly onto the machine take-up reel and
advances to the load-point (BOT) marker.
Tape Cartridges.—Tape cartridges are even easier
to load. Tape cartridges consist of a reel of tape and a
take-up reel enclosed in a protective case similar to the
cassette tapes you are familiar with, only larger. Here,
you simply mount the entire tape cartridge on the tape
unit and depress the proper keys/buttons. The tape
automatically loads. Your hands never come in contact
with the tape. The cartridge type of tape unit also works
under vacuum control and threads the tape in the same
manner as self-loading tape units.
DISMOUNTING A TAPE.— When a job finishes
using a tape, the tape is normally rewound and unloaded
automatically. At that time, the ready light goes off.
This is an indication to you that the tape can be
dismounted and placed in its proper storage rack or
returned to the media library.
LABELING A TAPE.— In some installations, you
may be required to prepare the external tape label for an
output tape file.
On it, you will indicate such
information as the following:
l
l
l
l
e
The tape unit number (or drive number) where
the tape file was initially created
The date of creation
The job name or number
The identification or volume number
The tape usage data and other pertinent
information
STORING TAPES.— When not being used, tape
reels should be properly supported. The plastic canister
or tape strap is designed to fully support the reel. A tape
reel that is supported in any other manner may become
warped.
2-31
