A soft error occurs in a computer when a datum or signal is incorrect and interferes either with chip or system processes. While the name seems to imply an error with software, because of the word "soft", this is not the case. A soft error, unlike a hard error, will not cause permanent damage to the computer and can usually be corrected with a cold boot. Severe soft errors may require work to be done on the computer, but any work done will not require a change in the circuitry; only the data stored in the computer will need to be altered.
There are two levels of soft errors: chip-level and system-level. Chip-level is the less severe of the two and is caused when a positive charge enters a computer chip, changing the energy signal. This occurs when the chip begins to decay, which will take about 10 years or longer for modern computers. To fix this soft error, aside from rebooting the computer, the memory chips can be swapped out for newer chips. This will correct the decay problem, because the new chips will contain pristine materials.
The second, and more severe soft error, is a system-level error that can occur at any time and often affects the data bus. When datum is hit with a noise or static, the computer can mistakenly think this noise is a new bit of datum that needs to be processed. This is not a real bit, so an error occurs. On its own, this error can usually be fixed with just a boot. If the fake bit remains in the data bus, because the computer saves it into memory, then it can keep returning to cause the same error.
Correcting a soft error is usually easy. The most common repair method is shutting the computer down for several minutes and then turning it back on. Restarting a computer from the desktop will not fix the error, because power will remain in the computer with a restart, while a cold boot removes all power. While this commonly works, severe errors will need to be looked at by a technician, who will have to either change the chip or change the data process. No matter how severe the soft errors become, they will never affect the hardware, only the data being processed.
A hard error can appear similar to soft errors by affecting the computer’s processes. Unlike the soft variety, a hard error does affect hardware, usually memory chips, and cannot be corrected from a cold boot. In this instance, the memory chip must be replaced, not because it is decaying but because it is faulty.