Technical data

Starting Up and Shutting Down the System
4.4 Booting in an Emergency
4.4.1 Booting with Default System Parameters
If the current values stored in the parameter file have been incorrectly modified,
these incorrect values might cause the system to become unbootable. With a
conversational boot operation, you can reset the active values for all system
parameters to the default value.
Note that in most cases, Compaq recommends that you use AUTOGEN to modify
system parameters. In special cases, however, you can use a conversational
boot to modify a parameter value temporarily. To change a parameter value
permanently, you must edit MODPARAMS.DAT and run AUTOGEN. For
instructions, see Section 15.5.)
How to Perform This Task
1. Perform a conversational boot by following the instructions in one of the
following manuals:
• On VAX systems, refer to the most recent versions of the OpenVMS
VAX Upgrade and Installation Manual and the upgrade and installation
supplement for your VAX computer.
• On Alpha systems, refer to the most recent version of the OpenVMS
Alpha Upgrade and Installation Manual.
2. At the SYSBOOT> prompt, enter the following command:
SYSBOOT> USE DEFAULT
This command specifies that default values should be used for all parameters.
3. To avoid starting all layered products on a system that is not tuned for them,
possibly causing the system to hang, set the STARTUP_P1 system parameter
as follows:
SYSBOOT> SET STARTUP_P1 "MIN"
4. Enter the CONTINUE command to continue booting:
SYSBOOT> CONTINUE
5. When the system finishes booting, determine which changed parameter
caused the problem, and reset the parameter value. If you specified the value
for the parameter in the AUTOGEN parameter file MODPARAMS.DAT, fix
the value in that file and run AUTOGEN. For more information, see Section
15.5.
6. Shut down and reboot the system.
Example
SYSBOOT> USE DEFAULT
SYSBOOT> SET STARTUP_P1 "MIN"
SYSBOOT> CONTINUE
Username: SYSTEM
Password:
Starting Up and Shutting Down the System 4–9