There are two unfortunate realities of
the electronics age; the utility simply cannot provide the clean,
consistent power demanded by sensitive electronics, and the
customer is ultimately responsible for the health and safe
operation of his equipment.
A study by IBM has showed that a typical computer is subject to
more than 120 power problems per month. The effects of power
problems range from the subtle—keyboard lockups, hardware
degradation—to the dramatic—complete data loss or burnt
motherboards. According to a survey by the Yankee Group, almost
half of the corporations researched put their downtime costs at
upwards of $1,000 per hour, with nine percent estimating costs up
to or more than $50,000 per hour.
Clearly, businesses are becoming more and more reliant on a
utility power supply that is pushed beyond its capacity. Despite
advances in the capabilities of modern personal computers, a
momentary power outage is still all it takes to lose your data.
More dangerous is the loss of previously written files, or even an
entire hard disk, which can occur should a power problem strike
while your computer is saving a file. Network fileservers
constantly writing to disk are particularly susceptible.
Unfortunately the situation won't be getting better anytime
soon. It takes approximately a decade to get a new power plant
on-line, and concerns about nuclear power and fossil fuels have
stifled the construction of new generating facilities. In the
United States, for instance, spending on utilities has dropped
from 2.3% of the Gross National Product in the 1960's to less than
1% today.
It's been said that there are two types of computer users:
those who have lost data because of a power problem, and those who
are going to. Over the past few years, we've helped create a new
class... those who have recognized the need for protection and
taken steps to ensure that they're prepared for the inevitable.
Power problems are the largest cause of
data loss
Power Failure/Surge: 45.3%
Storm Damage: 9.4%
Fire or Explosion: 8.2%
Hardware/Software Error: 8.2%
Flood & Water Damage: 6.7%
Earthquake: 5.5%
Network Outage: 4.5%
Human Error/Sabotage: 3.2%
HVAC Failure: 2.3%
Other 6.7%
Source: Contingency Planning
The anatomy of a power disturbance
Surges, spikes, blackouts and brownouts...what really happens
to your computer when it experiences an out-of-bounds power
anomaly?
We'll use a nearby lightning strike as an example, although it
is just one of countless problems that can strike your system.
Lightning strikes a nearby transformer. If the surge is
powerful enough, it travels instantaneously through wiring,
network, serial and phone lines and more, with the electrical
equivalent force of a tidal wave. The surge travels into your
computer via the outlet or phone lines. The first casualty is
usually a modem or motherboard. Chips go next, and data is lost.
The utility responds to overvoltages by disconnecting the grid.
This creates brownouts and blackouts. If the voltage drops low
enough, or blacks out, the hard disk may crash, destroying the
data stored on the disk. In all cases, work-in- process stored in
cache is instantly lost. In the worst case, password protection on
the hard drive can be jumbled, or the file allocation table may be
upset, rendering the hard disk useless.