Self-Test
When the machine first powers up, the boot ROM gets control. Before transferring control to a
system by booting it, the boot ROM has several responsibilities.
Hardware Initialization Support.
Some hardware must be initialized as soon as possible after power-up to prevent improper
operation. Exaulples are display initialization and floating RAM positioning, neither of which
can wait for an OS to be loaded.
Assembly Self-Test Support.
Self-Tests have about 95% confidence that a tested logic assembly is functioning properly. The
reason for these tests is to tell the user that the computer is okay. This consists of indicating all
installed accessories in the computer (and bus expander, if connected) and reporting all detected
failures.
Boot ROM self-test routines may not identify and indicate all hardware failures correctly. Several
things contribute to this. They include hardware design and the fact that testing for 100% of
all failure types is virtually impossible.
Several
UNEXPECTED
failures that can be displayed on the monitor are explained in Chapter 4.
These messages have the following format:
Boot Rom Functions
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