open-reel tapes and will help eliminate tape cling. All
tapes should be cleaned and certified annually.
CERTIFICATION. Tape certification requires
the use of a tape certifier machine. A tape certifier
performs digital and analog evaluations of a tape against
a calibrated standard. The objective of the certifier is
to exercise the tape far in excess of the operational
requirements of its tape unit.
The tape certifier checks the ability of the tape to
record high-density data, to retain magnetic flux
patterns, and to be demagnetized. The certifier
performs tape cleaner functions before testing the tape.
It also leaves the tape completely erased after testing.
Tapes that are certified error free to a particular density
will, in all probability give months of error-free
performance. Tapes that cannot be certified should be
DEGAUSSING. A degaussing machine is in
effect a big tape eraser. The machine applies an
ac-induced electromagnetic field of varying strengths
to the tape. The field completely nullifies all the
magnetic flux patterns stored on the tape.
Degaussing provides for a complete erasure of all
information stored on a tape. It maybe used to remove
classified data from tape as specified in the ADP
Security Manual, DOD 5200.28-M, sections VII and
STRIPPING. Magnetic tape tends to show the
greatest wear on the portions of the tape immediately
following the BOT marker. Seldom is an entire tape
reel used to store data; only a third of the tape or less is
used for storing data in most applications.
Excessively worn or damaged areas of tape maybe
stripped (cut away) from the reel, and a new BOT
marker installed on the tape. Stripping is a useful tool
for those installations that do not have tape cleaners or
NOTE: Do not strip open reels down to less than
500 feet of tape, since the remaining usable storage area
is limited. Standard reels containing less than 500 feet
of tape should be discarded.
SPLICING. Taping together two broken ends of
tape to make one tape is called splicing. Splicing is not
recommended for the following reasons:
. Tape splices are generally the weakest point on
the tape and could separate during operation
l Read and write operations may not perform
properly in the area of a splice; tape splices may appear
as bad spots on tape
l Splicing a broken tape usually does not save the
data stored on the tape
Open-reel tapes that break may be stripped to the
break and have a new BOT marker installed. This way
the remaining tape on the reel maybe used effectively.
Discard cartridges or cassettes that have tape breaks.
Of major importance to you as a technician is the
amount of attention paid to the control of magnetic
tapes. Nothing is more embarrassing or potentially
destructive than the loss of the last copy of a
maintenance program, operational program, or data file.
The least problem such a loss could cause would be the
time lost in regenerating or acquiring a new copy of the
program or data. The worst problem that could result
would be the degradation of a major tactical system or
capability when needed the most.
Tape control can be divided into the following
Program master/working copies
Identifying and correcting problems with tapes
TAPE INVENTORY. Each tape, cartridge, or
cassette used in a system must be accounted for by
number and have its contents identified by a label. A
tape label should contain the system location, program
or data designation, unit used to generate the tape,
security classification, and date the tape was written.
For tapes containing more than one program, a
complete listing of all programs, data files, and so forth,
should be included in the label.
A written inventory should be maintained
indicating programs or data stored on each tape and the
security classification of the tape. Tapes containing
classified information retain their security classification
until properly degaussed or the tape is destroyed.
P R O G R A M M A S T E R / W O R K I NG
COPIES. Tapes, cartridges, and cassettes generally
enter a computer system in one of three states:
c New (blank and certified)
l Used (cleaned, blanked, and certified)