"w_tom" wrote in message
...
Hard drives can be corrupted for various reasons based also
upon what the filesystem is. For example, if using FATxx
filesystems, then a loss of electrical power at the right time
can even erase files from that drive. Just another reason why
the technically informed want NTFS filesystems on drives; not
FAT.

Transients should never be a problem to disk drives or
memory. Based upon how these devices are connected, then a
differential type transient would be required to cause
damage. But all minimally acceptable power supplies must have
the essential function called overvoltage protection - that
makes a differential transient not possible.

That is the theory as well proven by power supplies even 30
years ago. Reality is the gross profits obtained by dumping
inferior supplies in North America where so many computer
assemblers don't even have basic electrical knowledge. Many
clones are not built and sold missing the essential
overvoltage protection because the assembler only understands
one specification - dollars. It's called a bean counter
mentality. If the power supply is sold on the cheap, (ie full
retail price is less than $60), then this and other critical
functions are simply *forgotten*. Does not matter. Consumer
is only to be fleeced.

If the destructive differential transient does occur, there
is no overvoltage protection circuit to protect that hardware
- do to power supply purchased by a bean counter. No
problem. Myth purveyors then quickly blame speculated surges,
and recommend overpriced, typically undersized, and
ineffective plug-in protectors.

Up front - does the power supply specifically state that
overvoltage protection is provided? If not, then it probably
is a man-made disaster just waiting to destroy disk drive,
data, and other computer components.

This overvoltage protection is something completely
different from another disk drive threat to FAT filesystems -
blackouts and brownouts.

A brownout is generally recognized as planned voltage cuts - or
undervoltage.
My utility in the US routinely implements 3% and 5% voltage cuts to shave or
reduce peaks (and thereby save $' when buying power).

There is also the issue of spikes and harmonics.

Given a current laptop/desktop will be ~ $800USD to ~$4000 for a high
performance system and a UPS sells for $40 - why subject a computer
to unexpected power events? What is the value of the data on the hdd(s)?


"J.J." wrote:
Does anyone have a reference to HDDs getting corrupted by
power events on the mains power supply?