NonStop Operations Guide for H-Series and J-Series RVUs

Writing Efficient Startup and Shutdown Command Files
TACL and by many subsystems support command files. Command files for startup or shutdown
contain a series of commands that automatically execute when the file is executed. To automate
and reduce the time required to start and stop your applications, devices, and processes:
• Include commands in one or more command files that you invoke from either a TACL prompt
or another file.
• Write efficient startup and shutdown command files.
Use command file syntax that executes quickly.◦
◦ Avoid manual intervention to ensure that command files execute quickly
◦ Use parallel processing to distribute startup and shutdown processes across multiple
processors.
◦ Investigate and use product-specific techniques for fast startup and shutdown.
Command File Syntax
The syntax in command files affects the time it takes for them to execute. To ensure that your
command files execute quickly:
• Avoid using wild-card characters in command files
A wild card is a character—typically an asterisk (*) or a question mark (?)—used to match
any character or series of characters. When you use wild-card characters in your command
files, execution time is increased because the system must look up names in a table. By using
explicit names instead of wild-card characters, you shorten execution time and allow for
commands to execute in parallel.
This PATHCOM START command uses a wild-card character to start all of the TERM objects
defined in the PATHMON configuration file:
= START TERM *
This PATHCOM START command uses explicit names to start all of the TERM objects defined
in the PATHMON configuration file:
= START TERM (TERM1, TERM2, TERM3, TERM4, TERM5, TERM6)
NOTE: When using explicit names, you must revise your command files whenever a
configuration change occurs. Therefore, you should balance the time it takes to update
configuration files against the savings in startup or shutdown time.
• Use single-line commands instead of multiple-line commands. Multiple-line commands in a
command file increase execution time.
Avoid Manual Intervention
Write startup and shutdown files so that they execute correctly without requiring manual intervention.
Any time an operator must intervene, startup and shutdown time increase and the possibility of
human error increases.
Use Parallel Processing
Parallel processing decreases the time required to start up or shut down your system or application
because startup and shutdown processes are distributed throughout the processors in your system.
For example, this SCF command file uses parallel processing in four processors to start several
206 Creating Startup and Shutdown Files