Summer,
Static, and Thunderstorms - Protecting the Availability of
your Data:
By: W.P. Flinn
Who would even think that part
of computer security deals with static electricity and
thunderstorms? Why do we care, from a security
standpoint, if the humidity is too high, or if there are
looming thunderstorms? Computer
security has three distinct aspects that make up a
well-rounded security posture - Confidentiality, Integrity,
and Availability, or what is commonly known as the C-I-A
triad. Several articles so far have discussed how to
keep your data safe from prying eyes and how to keep you
from becoming victims of phishing and social engineering - things that
mostly deal with confidentiality of your data.
But part of what we consider to be very important in the
computer security world is the idea of making sure that you
can get to your data whenever you need to - the
availability aspect of C-I-A.
This time I would like to talk about the environmental (and
other) things that can threaten the availability of your
data. More importantly, if something damages your
computer and takes away immediate availability, are you sure
the data itself wasn't damaged or destroyed? What's
the plan for getting it back? After all, if your
computer becomes damaged then you won't have access to your
information when you need it. Even worse - unless you
know the dangers and the ways to protect your data, you may
lose it entirely. Even if you just have a small
business at home, this can be devastating. How much
damage would be done if you lost all of your business
accounting records, client contact lists, and even saved
email messages? Home users
- would you care if several years of your income tax
returns, digital photos, and even secret family recipes were
suddenly lost forever?
Static Electricity:
Depending on where you live and
even what season it is, static electricity can be a real
problem. Computer electronic components are made of
very dependable yet extremely sensitive components.
Without going into the realms of physics or electronic
theories about computers, I can simply tell you that the
chips used in computers today are very sensitive to even the
slightest over-voltage condition. Static electricity
typically consists of a very fast discharge of voltage from
one surface to another. Voltage is literally the
"force" that drives electricity. The current involved
is of almost insignificant values, but the voltages can be
very high - and it this sudden "kick" of electromotive force
(the technical name for voltage) that causes the most
damage.
Static electricity is caused
mainly by friction between two surfaces, one of them usually
being an insulator. In fact, believe it or not,
one of the purposes (or side effects) of insulators is that
they store voltages. Two surfaces are rubbed
together and a process known as "triboelectric charging"
takes place. Like rubbing wool and plastic
together. Or how about rubbing a balloon on your
shirt, then the balloon sticks to you? This is static
electricity. The electrons are stripped from one
surface by friction, leaving an excess negative charge on
one surface and a relatively positive charge on the other.
Opposite charges attract - just like in magnetism. This can happen by something as simple as your clothing
rubbing against your body. Then, when you touch
something that has a different charge than you do - metal,
electronics, door knobs - the charge dissipates as the two
different voltage potentials try to "even out" their
potentials.
Static electricity can be
completely invisible. It takes as little as 50 to 100
volts of sudden discharge to damage electronic components.
You can discharge this much voltage - and more - without
even seeing or feeling it. In fact, you usually don't
see the discharge until about 3,000 volts. You
typically hear the discharge and see the little blue
lightning bolt at levels significantly higher.
Here's an example: I remember shuffling my feet (in
socks) across the carpeted floor in my grandma's living
room. Then I would touch the metal guard in front of
her fire place - because I thought the little blue lightning
bolt was cool. That represents an electrostatic
discharge of between 5,000 and 15,000 volts. It only
sounds like a lot - it is an instantaneous discharge, with
very little current. Remember - it's the amps
(current) that kills you, not the volts.
Unfortunately, it's usually the volts that kill your
sensitive electronic components.
There are a number of
antistatic strips you can buy that will aid in the
prevention of damage. Essentially what you are doing
is touching a conductive strip that is grounded. This
will effectively dissipate the static on your body to a
grounded surface and put your body at the same electrical
potential as your equipment. For those of you that
like to open your computers and do your own maintenance,
build your own computers, etc., make sure you are wearing an
ESD wrist strap to keep you from damaging your
equipment. A little simple and cheap insurance to
protect your equipment.
Temperature and Humidity:
In hot, dry climates static
electricity can be a real problem. In humid
environments, too much moisture can affect cooling and cause
corrosion. In Colorado, for instance, most home
heating and cooling systems include humidity control
equipment to compensate for the different amounts of
relative humidity from season to season.
Here's an example of how
humidity can damage your computer: A laptop computer left in a cold
car in winter, then brought into a nice warm room can suffer
from immediate condensation buildup. Many people have
asked me if it is okay
to turn a computer on after being left in the car (out in the cold) for long periods of
time. To answer this question, try this short experiment... put on your sunglasses, and go
stand outside in the cold air for about twenty minutes. (To keep busy, maybe shovel some
snow, or some other FUN activity!) Then, go back into your nice, warm house. Can
you still see? Or have your sunglasses fogged up? The "fog" on your sunglasses
is caused by the sudden temperature change from cold to warm effecting the moisture in the
air, and on the surface of your glasses (and computer). The warm air in your home or
office is hitting the cold glass or plastic on your glasses and causing condensation to
occur. The same thing is happening to your computer! When you bring it inside, especially
after being left in the car for a long time... don't turn it on for about thirty minutes.
Let the condensation dissipate first. This way, you will avoid possible water damage to
your system, or even a possible electrical short circuit.
Conversely, go from an extremely
hot and humid outdoor environment into a nicely air
conditioned house or office. The same thing can
happen. When I was in the Navy, we would come in off
of the carrier flight deck (130 degrees and VERY humid, in
the Persian Gulf) into the nicely air conditioned interior
of the ship - glasses would immediately fog up, camera
lenses would fog over, and it would take several minutes to
clear.
Unless you are installing
climate monitoring equipment, you won't really have an exact
idea of relative humidity in your environment. Just
use common sense. Make sure your heating and cooling
system has a humidity compensation device, and in extreme
conditions give your laptop a while to clear the
condensation before firing it up.
Thunderstorms, Ice Storms,
and Power Outages:
Thunderstorms are a very good
example of what can happen when static electricity is
happening on a grand scale. A lightning bolt is simply
a static discharge
between one potential in the upper atmosphere and another
potential on the ground. This type of static
electricity contains discharges of thousands of volts, and
is often deadly. This sudden discharge can
travel great distances along phone lines, household electrical wiring and
even cable television cables. Thunderstorms also cause power
outages and other sudden events that can cause surges in the
power going to your computer equipment.
In places with harsh winters,
such as the upper mid west, ice storms can stress aerial electrical
wiring, break them, and cause power outages. A
power outage can cause problems for you in that it suddenly
causes your computer to turn off without the benefit of the
normal shutdown procedure that safely closes files and lets
your computer close its operating system. This can
often result in corrupted or lost data files.
Also, these types of power outages are often accompanied by
several "off - on -off" surges, over voltage conditions, and
generally harmful activity for electronic components.
The most effective precautions
against power outages and electrical surges include the use
of such things as battery backup units (UPS units), and surge
protectors. When you know a thunder storm or other
severe weather is coming, simply turning off your equipment
and unplugging it is the best defense you can use. And
by unplugging it, I mean from the wall, the modem from the
phone jack, and your cable modem from the cable jack -
everything! Battery backup units will provide your
system with enough power to allow them to shut down properly
- which is in and of itself a very good way to prevent your
data from being corrupted. Most UPS units come with
software to automatically initiate the proper shutdown
process for you if you are not there to do it. Surge
protectors should always be used - whether you live
in areas with a lot of thunderstorms or not.
A Word About Backups:
One of the best ways to have
some assurance that all of your files will be kept safe,
even in the face of some of these potentially catastrophic
events, is to simply back up your data! With external
storage units becoming very inexpensive, you can back up
large amounts of data very easily. Practically all new
computers come standard with writeable CD-ROM units or DVD
units which allow you to easily copy your files to a media
that can be easily stored and kept safe - even put in a
safe-deposit box. Windows XP has a built-in utility to
make backing up your computer a snap. There are many
ways to back up your data - do it often, and make sure you
test those backups to ensure that the files are indeed
capable of being restored.
Summing it
all up:
Computer security is not only a
matter of keeping your data safe from prying eyes, but
making sure it is available when you need it as well.
There are a number of things that can harm your data - even
something as seemingly small as you shocking your computer
with static electricity. Power outages don't just make
the lights go out, but can also result in surges and other
events that harm your computer or cause it to shut down
improperly.
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