In this example, each of the maps listed is a system. In a systems audit, you take one or more maps and follow them through. A registration audit will sample every major system and most sub-systems.
Note that in a system audit, you will be looking at sub-systems. These may be called processes or procedures. Typically, procedures describe processes. The size and complexity of the company will determine how complex an issue this will be. In smaller companies, a system may provide all the information necessary while in larger companies there is extensive complexity.
An example of a document control system in a small company, for example, may be addressed in a single process map . If you start talking a Motorola sized business, the document control system is going to be quite complex, as you can imagine.
This becomes very important in planning an audit and in considering sample size. But - more about that later.
ISO 19011 - Quality and Environmental Management Systems Auditing Forum Discussions