Synchronisation: How Do Separate Processes Stay Aligned in Time?

Synchronisation does not make two processes do the same thing at every moment. It keeps their timing relationship within the tolerance required by a task. Two clocks may show the same reading now but gradually drift apart because they run at slightly different rates. Continuing synchronisation requires periodic comparison with a shared time signal and correction.

Three conditions are involved: the processes can change independently, they have a common reference that can be compared, and some mechanism adjusts detected drift. The adjustment need not reduce the difference to zero. A video call can tolerate a tiny offset between sound and image as long as it remains below the point where understanding suffers. In an ensemble, the parts need not play the same notes, but they must preserve shared beats and intended sequences.

Synchronisation differs from simultaneity: two events that happen together once may never align again. It is also narrower than coordination, which can organise roles, space and resources. Synchronisation specifically concerns temporal relationships. What matters is not perfect agreement at one instant, but whether divergence can be detected and corrected so the relationship remains usable.