System Overview 1-5
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Halt button. When the halt button is pressed, different results are manifest
depending upon the state of the machine. These states/results follow:
Machine State Result of pressing the Halt button
OpenVMS running/hung
Simple halt. The SRM console
runs.
DIGITAL Unix running/hung
Simple halt. The SRM console runs.
Windows NT running/hung
Ignored.
AlphaBIOS running/hung
Ignored.
SRM Console running
Sets halt assertion flag; the SRM console
continues to run.
SROM (1
st
2 secs. of pwr-up)
Not seen by the SROM firmware.
XSROM power up
Sets halt assertion flag; auto boot ignored
SRM console power-up
Sets halt assertion flag; auto boot ignored
1
A simple halt causes suspension of a system that is hung or running UNIX or
OpenVMS and drops back to the SRM console.
The halt assertion flag is a set in the TOY NVRAM; it is read
and cleared by the console only during powered up or reset.
When the SRM console finds the halt assertion flag set, the
conditions of the environment variables auto_action =
boot/restart and os_type = NT are ignored; the SRM console
runs and prints the following message:
Halt assertion detected
NVRAM power-up script not executed
AUTO_ACTION=BOOT/RESTART and OS_TYPE=NT ignored, if applicable.
P000>>>
Some reasons for using the halt button:
1.
The SRM console can be password protected. If the password is forgotten,
the Halt button can be used to regain control of the console. A new
password can then be set. See the AlphaServer 1200 User’s Guide.
2.
If the NVRAM power-up script becomes corrupt or is inadvertently
modified incorrectly, it can be bypassed and then edited by using the halt
button. See the AlphaServer 1200 User’s Guide.
Halt functions differ when operating the system remotely; see Appendix A
and C.
´
Reset button. Initializes the system.
1
Halt button pressed after the console checks whether to run NVRAM script but before it
checks auto_action results in the NVRAM script running but no operating system is booted.
