Sun Microsystems Sun Fire V440 Diagnostics And Troubleshooting Manual page 23

Finally, consider the different tasks you expect to perform with your diagnostic
tools:
Isolating faults to a specific replaceable hardware component
Exercising the system to disclose more subtle problems that may or may not be
hardware related
Monitoring the system to catch problems before they become serious enough to
cause unplanned downtime
Not every diagnostic tool can be optimized for all these varied tasks.
Instead of one unified diagnostic tool, Sun provides a palette of tools each of which
has its own specific strengths and applications. To best appreciate how each tool fits
into the larger picture, it is necessary to have some understanding of what happens
when the server starts up, during the so-called boot process. This is discussed in the
next chapter.
Chapter 1 Diagnostic Tools Overview 5