IBM RS/6000 - Manual (Page 177)

Memory
Processor
There are three levels of testing in Concurrent mode:
The Share-test level tests a resource while it is being shared by programs
running in normal operation. This test is mostly limited to normal commands
that test for the presence of a device or adapter.
The Sub-test level tests a portion of a resource while the remaining part of the
resource is being used in normal operation. For example, this test could test
one port of a multiport device while the other ports are being used in normal
operation.
The full-test level requires the device not be assigned to, or used by, another
operation. This level of test on a disk drive may require the use of
varyoff
operation. The diagnostics display menus allow you to vary off the desired
resource.
Error Log Analysis can be performed in Concurrent mode by selecting the Problem
Determination option on the Diagnostic Mode Selection menu.
To run Online Diagnostics in Concurrent mode, just enter the following command
as root:
diag
After a period of time (up to three minutes), you will be presented with the
diagnostics initial screen.
8.3.2 Service Mode
Running diagnostics in Service mode, provides the most thorough test of the
system resources available with Online Diagnostics. As in the Concurrent mode,
however, there are resources which cannot be tested. These resources are the
SCSI adapter and disks used for paging. Any ISA adapters which have been
configured to the system with AIX can be tested (providing diagnostics support is
installed for the adapters). You can also analyze the error log in this mode by
selecting the Problem Determination option on the Diagnostic Mode Selection
menu.
To access diagnostics from Service mode, perform the following steps:
1. Reboot your system.
2. When the POST icons are displayed, press F6 on the directly attached
keyboard or the number 6 key on the ASCII terminal keyboard, to indicate to
the system that the customized Boot Device Order List is to be used. Normally,
the first boot device in this list is your boot disk, which should also contain the
bos.diag package.
3. Enter any requested password (Power-On or Privileged-Access).
4. Follow any instructions to select a console.
Once diagnostics has loaded, you can follow the instructions given on the console
to test your system. After you have tested your system, you should exit
diagnostics, and follow the instructions displayed to "shut down" AIX. Failure to
shut down AIX could result in damage to data on your disks.
Chapter 8. Diagnostics Support 153