Power On Self-Test; Post Overview - Sun Microsystems Sun Blade 1000 Service Manual

3
C H A P T E R

Power On Self-Test

This chapter describes how to initiate power on self-test (POST) diagnostics. POST is
a firmware program used to determine workstation failures. POST verifies the core
functionality of the workstation, including operation of the CPU module(s),
motherboard, memory, and some on-board I/O devices. POST can be run even if the
workstation is unable to boot.
This chapter contains the following topics:
Section 3.1, "POST Overview" on page 3-1
Section 3.2, "Pre-POST Preparation" on page 3-2
Section 3.3, "Setting Up POST to Run in an OpenBoot PROM Environment" on
page 3-4
Section 3.4, "Maximum and Minimum Levels of POST" on page 3-5
3.1

POST Overview

POST detects most workstation faults and is located in the motherboard OpenBoot
PROM. POST is invoked optionally at power up by the OpenBoot program, and
depends on the setting of two environment variables; diag-switch? and diag-
level. The values for diag-switch? and diag-level are stored in nonvolatile
RAM (NVRAM).
Note – POST diagnostic and error message reports are displayed on a console
terminal.
3-1