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Which of the following is the most reliable, secure mea…

Which of the following is the most reliable, secure means of removing data from magnetic storage media such
as a magnetic tape, or a cassette?

PrepAway - Latest Free Exam Questions & Answers

A.
Degaussing

B.
Parity Bit Manipulation

C.
Zeroization

D.
Buffer overflow

Explanation:
A “Degausser (Otherwise known as a Bulk Eraser) has the main function of reducing to near zero the magneticflux stored in the magnetized medium. Flux density is measured in Gauss or Tesla. The operation is speedier
than overwriting and done in one short operation. This is achieved by subjecting the subject in bulk to a series
of fields of alternating polarity and gradually decreasing strength.
Incorrect Answers:
B: Parity has to do with disk error detection, not data removal. A bit or series of bits appended to a character or
block of characters to ensure that the information received is the same as the information that was sent.
C: Zeroization involves overwriting data to sanitize it. There is a drawback to this method. During normal write
operations with magnetic media, the head of the drive moves back-and-forth across the media as data is
written. The track of the head does not usually follow the exact path each time. The result is a miniscule
amount of data remanence with each pass. With specialized equipment, it is possible to read data that has
been overwritten. Degaussing is more effective than overwriting the sectors.
D: This is a detractor. Although many Operating Systems use a disk buffer to temporarily hold data read from
disk, its primary purpose has no connection to data removal. An overflow goes outside the constraints defined
for the buffer and is a method used by an attacker to attempt access to a system.


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