IBM RS/6000 - Manual (Page 94)

one of the icons will be the memory icon. During the display of this icon, an 8-digit
error code will be displayed if the L2 cache is not fully functional.
The remainder of memory is also tested, and if a failure is detected, an 8-digit error
code is posted. This error indicates which Dual Inline Memory Module (DIMM) slot
is at fault. The basic algorithm for the system memory configuration is as follows:
1. Query each memory slot to see if there is a memory DIMM installed.
If yes, determine its size. Identify each DIMM as IBM or non-IBM, ECC or
parity. This is done by querying special identification registers in the
DIMMs themselves.
If the DIMM could not be identified, display the memory slot number as well
as a warning saying that a DIMM could not be identified. Proceed with the
next DIMM.
2. Test the DIMM.
If this is an IBM DIMM and it passes the test, make it available and add its
size to the “available memory” quantity. If it doesn't pass the test, keep the
DIMM out of the system configuration, and display a warning on the screen
reporting the faulty DIMM slot number.
If this is a non-IBM DIMM and passes the test, make it available, and add
its size to the “available memory” quantity. In addition, display a message
on the screen reporting that a non-supported, non-IBM memory DIMM has
been found, tested and correctly configured. If the DIMM doesn't pass the
test, display a warning on the screen reporting that a non-IBM memory
module was found and failed to pass the test.
3. Proceed with the next DIMM.
At the end of this process, the system will have available all the memory it could
configure (IBM or not).
4.4.5.3 Graphics Adapter POST
The firmware does test the graphics adapter but not the display. The system will
give a speaker beep sequence when the graphics adapter is found to be
non-functional. The beep sequence is a one long beep, followed by one short
beep. The error is logged, and the system boot continues.
4.4.5.4 Keyboard and Mouse Controller POST
The keyboard/mouse controller has a built-in Power-On Self Test, and the firmware
checks the result. If an error is detected, an 8-digit error code is displayed; the
error is written to the Error Log, and the system continues.
4.4.5.5 SCSI Subsystem POST
The SCSI POST opens the adapter and runs several test scripts which check and
exercise the various functions related to the chips on the integrated SCSI adapter,
such as DMA, simulate mailbox commands, and so on. If an error is detected, an
8-digit error code is displayed; the error is written to the Error Log, and the system
continues.
70 Introduction to PCI-Based RS/6000 Servers