The Importance of Time and Synchronisation in Computing

Computers are now part and parcel of our daily lives and we often take them for granted. Whether we are starting our car, loading the washing machine or taking cash out of the bank, a computer is behind it.

We are also used to computers talking to each other, necessary when we are booking online tickets or drawing cash from the bank. Computers communicate by the way of timestamps, most computer transactions from sending and receiving emails to saving documents are reliant on a time stamp. Timestamps are merely the time the process commenced, next time you receive an email, check the time it was sent, it is quite possible the email was sent after you had received it, this is because the time on each machine is not synchronised.

For some transactions it is necessary for computers to be perfectly synchronised, even a few seconds difference between machines can have serious effects, such as finding an airline ticket you had booked had been sold moments later to another customer or you could draw your savings out of a cash machine and when your account is empty you could quickly going to another machine and withdraw it all again.

If machines were not synchronised then many time sensitive transactions could not happen so it is important that computers tell the same time. However, what time is best to synchronise to and how to all machines know the correct time?

Clocks and watches are everywhere but if you check the time on more than one device, chances are they are telling time differently. It may be a matter of seconds but as we have seen, seconds can make all the difference.

Fortunately there is an international standard time called UTC (Universal Coordinated Time), and the exact UTC time is broadcast by special radio transmissions or by the GPS network as a time code.

Computers can receive this time code by using a time server. Normally these servers use NTP (Network Time Protocol) which converts the time to a language the computer understands. NTP servers allow computers to synchronise to the exact same time no matter where they are in the world.

Without NTP time servers, computers would be unable to carry out task that we now take for granted such as online shopping, trading on the stock exchange or even drawing money from a cash machine.