Cisco Gigabit Ethernet Switch Module for HP p-Class BladeSystem Software Configuration Guide

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Chapter 3 Assigning the Switch IP Address and Default Gateway

Modifying the Startup Configuration

Controlling Environment Variables

With a normally operating switch, you enter the boot loader mode only through a switch console

connection configured for 9600 bps. Unplug the switch power cord, and press the switch Mode button

while reconnecting the power cord. You can release the Mode button a second or two after the LED

above port 1 turns off. Then the boot loader switch: prompt appears.

The switch bootloader software provides support for nonvolatile environment variables, which can be

used to control how the bootloader, or any other software running on the system, behaves. bootloader

environment variables are similar to environment variables that can be set on UNIX or DOS systems.

Environment variables that have values are stored in flash memory outside of the flash file system.

Each line in these files contains an environment variable name and an equal sign followed by the value

of the variable. A variable has no value if it is not listed in this file; it has a value if it is listed in the file

even if the value is a null string. A variable that is set to a null string (for example, “ ”) is a variable with

a value. Many environment variables are predefined and have default values.

Environment variables store two kinds of data:

• Data that controls code, which does not read the Cisco IOS configuration file. For example, the

name of a bootloader helper file, which extends or patches the functionality of the bootloader can

be stored as an environment variable.

• Data that controls code, which is responsible for reading the Cisco IOS configuration file. For

example, the name of the Cisco IOS configuration file can be stored as an environment variable.

You can change the settings of the environment variables by accessing the bootloader or by using Cisco

IOS commands. Under normal circumstances, it is not necessary to alter the setting of the environment

variables.

Note For complete syntax and usage information for the bootloader commands and environment variables, see

the command reference for this release.