In 2007, a team of Google engineers needed more accurate time for servers. Time is especially useful for synchronising data, and especially transactional data. Technologies like Cassandra depend on accurate time between database servers to be able to reconstruct the order-of-events on a database. The end goal is to be sure about the “State-of-Data”.
NTP (network time protocol) is what unix servers and internet machines use to synchronise time. Due to network delays or processing delays, a computer’s time can easily get out of sync with its peers. The margin of error has been minor, and the demand for high accuracy has been crucial. But for a large computing company like Google, keeping thousands of system accurate was important for them to create “Spanner“.
Spanner is the new time keeping platform that Google has constructed using GPS and an atomic clock. Fortunately the distances we have to cover is at most the span of the earth. I am sure the folks in NASA and other space faring agencies will have to consider time differences spanning larger quantums of space.
This is all in the effort to maintain the “State-of-Data”.