DEC 4000 AXP Service Manual page 21

ROM-Based Diagnostics (RBDs)
ROM-based diagnostics have significant advantages:
• There is no load time.
• The boot path is more reliable.
• Diagnosis is done in console mode.
RECOMMENDED USE: The ROM-based diagnostic facility is the primary
means of console environment testing and diagnosis of the CPU, memory,
Ethernet, Futurebus+, and SCSI and DSSI subsystems. Use ROM-based
diagnostics in the acceptance test procedures when you install a system,
add a memory module, or replace the following: CPU module, memory
module, backplane, I/O module, Futurebus+ device, or storage device. Refer
to Section 3.1 for information on running ROM-based diagnostics.
Loopback Tests
Internal and external loopback tests are used to isolate a failure by testing
segments of a particular control or data path. The loopback tests are a subset
of the ROM-based diagnostics.
RECOMMENDED USE: Use loopback tests to isolate problems with the
auxiliary console port and Ethernet controllers. Refer to Section 3.1.12 for
instructions on performing loopback tests.
Firmware Console Commands
Console commands are used to set and examine environment variables and
device parameters. For example, the
and commands are used to examine the configuration; the
show device
(bootdef_dev, auto_action, and boot_osflags) commands are used to set
set
environment variables; and the
parameters.
RECOMMENDED USE: Use console commands to set and examine
environment variables and device parameters. Refer to Section 6.2 for
information on firmware commands and utilities.
,
show memory show configuration
cdp command is used to configure DSSI
System Maintenance Strategy 1–9
,