|The NTP FAQ and HOWTO: Understanding and using the Network Time Protocol (A first try on a non-technical Mini-HOWTO and FAQ on NTP)|
Note: XXX Note from the editor: This part is still incomplete!
Computers are good in adding bits. Therefore time is stored in a number of bits, and adding to these bits makes the time go on. The meaning of the value "zero" has to be defined separately (Usually this is called the epoch).
Using more bits can widen the range of the time value, or it can increase the resolution of the stored time.
Example 2. Range and Resolution
Assume we use 8 bits to store a time stamp. There can be 256 different values then. If we choose to store seconds, our resolution is one second, and the range is from 0 to 255 seconds. If we prefer to store the time in minutes, we can store up to 255 minutes there.
With 64 bits you could have nanosecond resolution while still having a range significantly longer than your life.