Sun Microsystems Sun Fire X4140, Service Manual

Page: 133 / 168

B-1
A P P E N D I X
B
BIOS Power-On Self-Test (POST)
Codes
The system BIOS provides a basic power-on self-test (POST), during which the BIOS
checks the basic devices required for the server to operate. The progress of the self-
test is indicated by a series of POST codes. This chapter explains the BIOS POST
testing, provides an alternate method for viewing the codes, describes how to change
POST options, and lists the POST codes.
This chapter contains the following sections:
■
Section B.1, “Introduction” on page B-1
■
Section B.2, “How BIOS POST Memory Testing Works” on page B-2
■
Section B.3, “Redirecting Console Output” on page B-2
■
Section B.4, “Changing POST Options” on page B-3
■
Section B.5, “POST Codes” on page B-4
B.1 Introduction
The POST is a systematic check of basic system devices. As the testing progresses, the
BIOS displays codes that you can use to interpret the status of your server. The codes
appear at the bottom right corner of the system’s VGA screen, after the self-test has
progressed far enough to initialize the video monitor. Because the codes might scroll
off of the screen too quickly to be read, an alternate method of displaying POST
codes is to redirect the output of the console to a serial port (see
Section B.3,
“Redirecting Console Output” on page B-2 ).