Myths Debunked

PC Myths Debunked
Cyber world is Full of Myths, But we Explored the right ones Here ...

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Several myths exist about computers
and security. We 

put some of 

most the

intriguing ones to the test!

The RAM is emptied when a
PC’s power is switched off

THE MYTH: RAM is a short-lived

memory medium, in which the computer

stores running programs and opened

files to access them quickly. If one

switches off the computer then the RAM

becomes empty and data in it is lost.

THE TRUTH: RAM consists of individual

memory cells, which each represent one

bit. Each of these cells again consists

of a transistor and a capacitor, which

either contains an electrical charge

(bit-value 1) or not (bit-value 0). The

transistor regulates access on this

charge and is thus connected to two

electrical lines, the word line and the

bit line. During writing and reading

processes, the CPU always activates

the word line first, making the transistor

permeable. While writing, the CPU

transports information on the bit line.

The charge of the capacitor then aligns

with the potential of the bit line, which
corresponds to the value 1 or 0. The
capacitor deallocates its charge on
the bit line during the writing process,
whereby its potential rises or falls—
depending on whether the capacitor is
loaded or not. The CPU then interprets
this as 1 or 0. As the line is discharged
during reading, a fresh writing process
follows, which recovers the cell
contents (the “write-back” process).
A loaded capacitor saves only around
100,000 electrons in each capacitor at
that point. This minor charge quantity
can be cleared very fast by current
leakage in the surrounding material
of the chip, if one cuts the supply of
current. Thus the internal memory is
updated every 15 microseconds—ie
several thousand times per second—to
prevent this (“refresh”). The memory is
not empty in milliseconds, as few cells
discharge faster and others discharge
slower, depending on the design.
Most of the bits can in fact survive
at room temperature for at least two
seconds, but if one artificially cools
down the memory chips to minus 50
°C, then the charges remain for much
longer. Resistance is increased in the
semiconductor material of the memory
chips at this temperature. That prevents
fast discharging by current leakage. In
our field trial, a computer could wake
up even from standby mode, after we
had removed a cooled RAM stick and
inserted it again after few seconds.
This should not affect security for
ordinary users in any way, but it is
interesting that it is theoretically and
practically possible.

Magnets can erase the data on 
hard drives


THE MYTH: Magnets often come with

a note saying that magnetic fields may

erase the data on hard drives. Many

people therefore think that they will

lose data if they keep a magnet near a

computer or keep a hard disk on top of a

loudspeaker.

THE TRUTH: Magnets used to be really

lethal for data stored on floppy disks.

But even powerful Neodymium magnets

cannot really affect the data on hard

disks. Such magnets are also integrated

in the actuator that controls the readwrite

head inside the drive.

The stronger the magnets, the

faster the head can move over the disk,

to reduce access time.Modern-day

Terabyte-sized drives consist of up

to four platters that are coated with

iron oxide or cobalt and each have

capacities of up to 690 GB. This data is

stored in small magnetized segments

(bits) on the disk which can have two

magnetization directions: 0 and 1. Since

2005, bits have been vertically aligned