...

/

A Practical Perspective

A Practical Perspective

Let's look into the practical perspective of clocks and time in distributed systems.

The clocks used in real systems are what we usually call physical clocks.

Physical clock

A physical clockC. Dyreson, “Physical Clock,” Encyclopedia of Database Systems, 2009. is a physical process coupled with a method of measuring that process to record the passage of time.

Most physical clocks are based on cyclic processes. Below are some examples of such devices:

Sundial

A sundial is one of the most basic and easy-to-understand devices. It tells the time of the day by using a gnomon and tracking the shadow created by the sun.

Press + to interact

Hourglass

An hourglass is also a basic and easy-to-understand device. It measures time by the regulated flow of sand through a bulb.

Press + to interact

Pendulum clock

A pendulum clock is a common clock device that uses an oscillating weight as its timekeeping element.

Press + to interact

Quartz clock

A quartz clock is an electronic version of the pendulum clock and is used in software systems. This device makes use of a crystal, called quartz ...