User`s guide

As shown in Figure 3-1, the sequence of events is essentially the same for all actions initiating a cold start.
The sequence of events for each action
is outlined in the following paragraphs.
o Power-Up Cold Start Sequence - A power-up cold start of the operating system causes the
console subsystem to perform the following sequence of events:
o
• Execute the self-test, load the console program (Chapter 2), and check the setting of the
AUTO/RESTART switch. If the switch is set to the OFF position, the CPU enters the
console
I/O mode wait loop. However, if the switch is set to the ON position, the console
subsystem prints the message
ATTEMPTING SYSTEM BOOT on the console terminal.
• Examine the cold start flag. If the flag is set, indicating a cold start has previously been
attempted, the message
SYSTEM BOOT FAILED is printed on the console terminal. The
CPU then enters the console I/O mode wait loop. However, if the cold start flag is not set,
indicating
that a cold start has not been attempted, the console subsystem sets the cold
start flag.
• Execute the indirect command file (XXXBOO.CMD) associated with the type of cold
start to be performed. This file executes the functions necessary to cold start the operating
system.
Warm Start Failure Cold Start Sequence - The failure of a warm start causes the console
subsystem to perform the following sequence
of events:
• Check the setting of the AUTO/RESTART switch. If the switch is set to the OFF
position, the console I/O mode wait loop is entered. However, if the switch is set to the ON
position the console subsystem prints the message ATTEMPTING SYSTEM BOOT on
the console terminal.
• Examine the cold start flag. If the flag is set, indicating a cold start has previously been
attempted, the message
SYSTEM BOOT FAILED is printed on the console terminal. The
CPU then enters the console I/O mode wait loop. However, if the cold start flag is not set,
indicating
that a cold start has not been attempted, the console subsystem sets the cold
start flag.
• Execute the indirect command file (XXXBOO.CMD) associated with the type of cold
start to be performed. This file executes the functions necessary to cold
start the operating
system.
'
e Console I/O Mode BOOT Command Sequence - Typing the BOOT command at the console
terminal while the
CPU is in the console I/O mode wait loop causes the console subsystem to
perform the following sequence
of events:
• Set the cold start flag.
• Execute the indirect command file (XXXBOO.CMD) associated with the type of cold
start to be performed. This file executes the functions necessary to cold start the operating
system.
3-3