Why are computer clocks so inaccurate?
The National Institute of Standards and Technology — the keeper of the atomic clock — has found that computer clocks are inaccurate due to the design limitations of the first PCs. The problem arises from the use of two time keeping systems in every computer. One resides in the computer’s hardware, the other is maintained by the operating system’s software. The hardware clock runs continuously, but is often inaccurate because of design limitations, temperatures changes, and diminished battery voltage. The software clock starts as the computer is booted and is set from the hardware clock. While the software clock is more accurate, it relies on the hardware clock (which can be off several minutes each day) for its initial and periodic settings.
