When I recently priced out a new PC, I opted for one that had as
a standard feature error correction code (ECC) memory -- a type
of system memory that supports advanced error correction. I was
concerned that without ECC, I'd be more prone to memory errors
and was willing to pay a little extra for the insurance policy.
There's no question ECC memory comes at a premium. Not only is
the memory itself more expensive, but the technology required to
support it must be built into the motherboard of the computer
that uses it (which, in turn, raises the price of the system
again). To understand what ECC is really for, you have to delve
into the history of commodity PC memory. History of error
correction in memory When the desktop PC first appeared, memory
was not only an expensive commodity, but it was also far more
prone to errors than it is today. The traditional stopgap for
memory errors was a technique called parity, where each byte of
memory had an additional ninth bit associated with it as an
error-checking meas