Sun Microsystems SPARCstation 20, Руководство по обслуживанию

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12 SPARCstation 20 Service Manual • July 1996
OpenBoot PROM Diagnostics
On-board diagnostics are executed from the
ok
prompt. If there is a problem with
the operating system, the system will default to the
ok
prompt. The
ok
prompt can
also be accessed by shutting down the operating system.
TABLE 2-3
describes selected OpenBoot PROM diagnostic tests and what must occur
before each test can be executed. Some of the tests verify the proper operation of the
network controller, while other tests verify the diskette drive system, memory, and
system clock. Appendix E provides a detailed description of each test.
TABLE 2-2
Autoboot and Diagnostic Switch Settings
Autoboot Switch Diagnostic Switch Result
False Either true or false
ok
prompt (OpenBoot PROM commands)
True False Boot operating system from disk (default)
True True Boot operating system from network
(default)
TABLE 2-3
OpenBoot PROM Diagnostic Tests
Type of Test Description Preparation
test screen
Tests the video graphics hardware and
monitor The
diag-switch?
NVRAM parameter must
be set to true.
test floppy
Tests the diskette drive response to
commands Insert a formatted diskette into the drive.
test scsi
Tests the system board SCSI interface
logic The
diag-switch?
NVRAM parameter must
be set to true.
test net-aui
Performs an internal and external
loopback test on the AUI (Thick)
Ethernet interface A cable must be connected between the rear
panel AUI Ethernet port and the Ethernet
transceiver.
test net-tpe
Performs an internal and external
loopback test on the TPE interface A cable must be connected between the rear
panel TPE port and a TPE hub. If the
tpe-
link-test?
parameter is false (disabled), the
external loopback test will appear to pass even
if a cable is not connected.
test net
Performs an internal and external
loopback test on the auto-selected
system Ethernet interface A cable must be connected between the system
and the Ethernet transceiver or hub.