While the mechanical configuration of modern hard disk drives suggests that
they are fragile and error prone, actual experience is different.
Technically, removable media such as CD is probably safer, providing it is
good quality media and it is handled and stored properly, but the current
reality is that for many people hard disk drive backup is just as reliable,
especially when the time frame for which backup data needs to be kept is
typically quite short.
--
Jeff Richards
MS MVP (DTS)
"Brad" wrote in message
...
Hi "Lil' Dave",

HDDs have many vulnerabilities, therefore I would not trust them for
keeping important files or OS backup. The heads are only microns from the
surface of the spinning platters. A sudden jolt could cause the head to
bounce off the platter surface, or if "writing", overwrite data on an
adjacent
track/s. The platters spin at high speed on a shaft with bearings. A
motor
spins the platters. There is a printed circuit board with many
semiconductor
devices mounted on it (part of the HDD assembly), some of these devices
are
MOS devices. A power line surge can possibly damage one or more of these
devices. What is the long term retention of magnetism (chain of
microscopic
magnetic dots representing data) on the platters?

If a CD/DVD rom drive goes bad, you simply replace it since your import
files, etc. are on CDs (removable media). On the other hand, a HDD does
not
have removable media.