Service manual

Examples 2-1
Chapter 2
Examples
Online addition and replacement of CPUs is used to expand capacity, upgrade
components, and replace failed components, while the operating system
continues to run.
Following are the steps required to replace a CPU. Step 3 is the physical
replacement of the CPU; the other steps are performed at the operating system
level.
1. Take the CPU offline.
2. Remove power from the CPU. When power is removed, the yellow LED on
the CPU module lights indicating that the CPU module may be safely
removed.
3. Physically remove the CPU and insert another CPU module.
4. Restore power to the CPU. Self-test begins and lasts 7–10 seconds. The
yellow LED on the CPU goes out and the green LED lights.
5. Put the CPU online so that the operating system can use it.
Section 2.1 shows how to handle the CPU modules. Examples of the procedure
for each operating system are given in the following sections.