Background Concepts

In this section we will discuss the fundamentals of timekeeping in real and virtual machines.

Host Timekeeping

This section will provide a brief overview of timekeeping in stand-alone or host PCs/servers.

todo: add a diagram of a simplified timer showing oscillator, counter, counter input, and interrupt
todo: explain the parts of the diagram

This section will explain why timing is different for guest operating systems.

Discuss what causes the problem in virtual environments. Consider para-virtual and full-virtual architectures.

Discuss the impact of error on a few real-world applications.

Discuss common strategies in VM software and in operating systems to compensate for drift. Discuss what happens when the clock is slow and fast.