Service manual

Chapter 4 Diagnostics
37
Advantages and Limitations of Hardware Diagnostics
Off-line diagnostic software is useful in making sure that has been eliminated as the cause for possible
system problems. Such diagnostic tools can easily be shipped with a server, and they are relatively easy to
use.
However, off-line diagnostic software should be used only by experienced personnel who can take a wider
view of its limitations, which include:
• booting the server from the diagnostics diskette
• no access to operating system error logs, since the OS is not operating at the same time as the
diagnostic tools
• limited ability to test only a single component at a time
• inability to indicate problems with wrongly configured systems or the network
Event Log Display Utility
This utility shows events logged in the System Event Log (SEL) and provides advisory information. Brief
descriptions of the events are also available through the front panel LCD display. To access this utility, boot
the system with the Navigator CD-ROM in the CD-ROM drive. When the Navigator Main Menu comes up,
select "NetServer Utilities", then "More NetServer Utilities," and then "Event Log Report Utility."
Be patient. The utility may take a while to read the event log from non-volatile memory.
The Event Log Display Utility is also available through DiagTools.
POST Routines
The POSTS executed during startup are:
Test Description
Processor Test
Tests the processor's registers. Test failure causes an error message to be
displayed and the boot process to abort.
System (BIOS) ROM
Test
BIOS ROM chip calculates an eight-bit checksum. Test failure causes an error
code to be displayed and the boot process to abort.
Memory Subsystem
Test
Tests the physical configuration of the memory subsystem. The test checks for
valid memory module combinations. Test failure causes an error code to be
displayed.
RAM Refresh Timer Test
Tests the RAM refresh timer circuitry. Test failure causes an error message to
be displayed and the boot process to abort.
Interrupt RAM Test
This test checks the first 64 K of system RAM used to store data corresponding
to various system interrupt vector addresses. Test failures cause an error
message to be displayed and the boot process to abort.
CMOS RAM Test
Checks the CMOS RAM for start-up power loss, verifies CMOS RAM
checksum. Test failure causes error codes to be displayed.
Cache Memory Test
Tests the processor's internal cache RAM. Test failure causes an error
message to be displayed and the boot process to abort.
Keyboard/Mouse
Controller Test
Checks for proper operation of the Keyboard/Mouse Controller. Test failure
causes an error code to be displayed.
Timer 0/Timer 2 Test
Tests Timer 0 and Timer 2. Test failure causes an error code to be displayed.
DMA Sub-system Test
Checks the DMA controller registers. Test failure causes an error code to be
displayed.