How Magnets Affect Computer Disks

How Magnets Affect Computer
Disks

BackGround

One of the most commonly used Computer data storaged mediums is a Computer
Disk or a Floppy. These are used in everyday life, in either our workplace or at home.
These disks have many purposes, such as:

Storing data: Floppies can be used to store software/data for short preiods of time,

Transferring data: Floppies are used to transfer/copy data from one computer to
another.

Hiding data: Floppies are also sometimes used to hide sensitive or confidential data,

because of the disk's small size it can be hidden very easily.

Advertising: Because floppies are cheap to buy, they are used to advertise different types

of software, such as: Software for the internet advertised on America Online Floppies.

Floppies are also considered to be very sensitve data storage mediums. These
Disks have numerous advantages and disadvanteges. Even though floppies are used so
commonly they are also not very dependable. They have numerous conditions under which
they should normally be kept. For example: the actuall magnetic disk inside the hard cover
of the disk must NEVER be touched, the magnetic disk inside, must be protected by the
metallic sliding shield, the disk must always be within the temperature of 50° to 140°
Fahrenheit and the disk must never be bought near a magnet! (3M Diskettes)

There are many such hazards to computer disks. Problems caused by magnets are
very common. A floppy can be damaged unknowingly if it is kept near a magnet, that may
be in the open or inside any device, such as a speaker phone in computer speakers or
stereo or a telephone. And becuase of the common use of magnets in everyday life, more
and more floppies are damaged everyday.

Even though protective coverings against magnets and other electrical hazards, are
available for floppies, they are not used very commonly. Therefore, floppies are not a very
safe media for storage, even though they are convienient.

Some of the most commonly used diskettes are by 3M and Sony and other such
companies. The floppies are sold in boxes with instructions on them to not to bring
floppies near magnets and other instructions of DOs and DONTs. These instructions must
always be followed.

Floppies have different capacities such as 720 KB (kilobytes) and 1.44 MB
(megabytes). Floppies also have different sizes, 3.5" and 5.25". The most commonly used
floppy is usually 3.5". It is not soft and cannot be bent, where as a 5.25" disk is soft and
can be bent!

A floppy is a round, flat piece of Mylar coated with ferric oxide, a rustlike substance
containing tiny particles capable of holding a magnetic field, and encased in a protective
plastic cover, the disk jacket. Data is stored on a floppy disk by the disk drive's read/write
head, which alters the magnetic orientation of the particles. Orientation in one direction
represents binary 1; orientation in the other, binary 0.

Purpose

The purpose of my experiment was to test Floppies to see how delicate they are
near magnets and how much damage can be done to the disks and to the software on it
bye a single magnet. I also hope my project will help others to be aware that computer
disks are very delicate and sensitive to temperature, weather, magnets...etc.



Hypothesis

When the magnets are bought near the disk, the disk should be damaged internally
along with the software in it. And the weakest magnet should cause the least damage and
the strongest magnet should cause the most damage.



Experimentation

Material:
Four 3.5" Floppy Diskettes.
Four different Magnets
One Personal Home Computer
Printer
Software:
Windows95
Norton Disk Doctor
Dos (Ver 4.00.950)


Procedure:

Every Floppy Diskette has 2874 sectors. This was calculated by dividing the total
number of bytes on a disk by the number of bytes every sector occupies. There is a total of
1,457,664 bytes on every Floppy, and every sector occupies 512 bytes. Therefore, 512 /
1457664 is 2874, ie. the total number of sectors on every Floppy.

First, I obtained the four 3.5" IBM formatted floppy diskettes (Highlandä). Next I
obtained the four different magnets of different strengths and sizes and tested and verified
their strengths by bringing iron filings near each of them and observing how much of iron
filings each one of them attracted and then noting which magnet was the strongest and
which was the weakest in order. Then I tested each of the disks for existing errors by
using a program called Norton Disk Doctor (NDD) which has the ability to detect and fix
error on a disk. There were no error on any of the four disks.

Next, I decided to hold the magnets near the disks for the experimentation for
about 30 seconds at about the same place on the disk. I did so on all of the four disk.

Then, I brought the disks home and tested all four of the disks in a disk testing and
repair program called Norton Disk Doctor. I notices that each one of the disks suffered
damage.

Every one of the four disk was numbered. The Floppy with the weakest magnet
was "Disk 1" and the Floppy with the strongest magnet was "Disk 4" respectively. This
was done to avoid possible confusion in the disks.


Result

Every Floppy Diskette has 2874 sectors. This was calculated by dividing the total
number of bytes on a disk by the number of bytes every sector occupies. There is a total of
1,457,664 bytes on every Floppy, and every sector occupies 512 bytes. Therefore, 512 /
1457664 is 2874, ie. the total number of sectors on every Floppy.

After every Floppy had been tested, I noted all the results. The results were as
follows:

Disk 1:

Total Bytes on Disk: 1,457,664
Total Bytes in Bad Sectors: 3584
Total Number of Sectors: 2874
Total Number of Bad Sectors: 7
Total Number of Good Sectors: 2867

Disk 2:

Total Bytes on Disk: 1,457,664
Total Bytes in Bad Sectors: 5632
Total Number of Sectors: 2874
Total Number of Bad Sectors: 11
Total Number of Good Sectors: 2863

Disk 3:

Total Bytes on Disk: 1,457,664
Total Bytes in Bad Sectors: 15360
Total Number of Sectors: 2874
Total Number of Bad Sectors: 30
Total Number of Good Sectors: 2844

Disk 4:

Total Bytes on Disk: 1,457,664
Total Bytes in Bad Sectors: 19968
Total Number of Sectors: 2874
Total Number of Bad Sectors: 39
Total Number of Good Sectors: 2833

After the testing, I discovered that even the smallest of the Magnets could cause
bad sectors and damage both, the disk and the data on the disk. Even thought the damage
wasn't very big, it was big enough to corrupt any program on the disk, becuase every part
of the present file would be necessary for its correct use and any bad sectors would almost
destroy the file and make it worthless.



Conclusion:

In conclusion, this experiment proved that floppies are very sensitive to magnets
and should not be brought near them at anytime. When the magnets were brought near the
floppies, the disks were damaged and the weakest magnet caused the least damage and the
strongest magnet caused the most damage.