Specifications

2-20
System Management Software Configuration Guide for Cisco IE 2000U and Connected Grid Switches
Chapter 2 Assigning the Switch IP Address and Default Gateway
Assigning Switch Information
• On a PC running Windows 2000, Ctrl-Break is the break key.
Cisco TAC has tabulated break keys for most common operating systems and provided an alternative
break key sequence for terminal emulators that do not support the break keys. To view this table, see:
http://www.cisco.com/en/US/customer/products/hw/routers/ps133/products_tech_note09186a0080
174a34.shtml
When you enter the break key, the boot loader switch: prompt appears.
The switch boot loader software provides support for nonvolatile environment variables, which can be
used to control how the boot loader, or any other software running on the system, behaves. Boot loader
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 boot loader helper file, which extends or patches the functionality of the boot loader 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 boot loader 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 boot loader commands and environment variables,
see the command reference listed in the “Related Documents” section on page 2-25.