Cisco 7604 Configuration Manual page 70

Modifying the Supervisor Engine Startup Configuration
Table 3-2
Bit Number
11 to 12
13
14
15
1. The factory default value for the configuration register is 0x2102.
2. OEM = original equipment manufacturer.
Table 3-3
Boot Field Meaning
00
01
02 to 0F
Modifying the Boot Field and Using the boot Command
The configuration register boot field determines whether or not the router loads an operating system
image, and if so, where it obtains this system image. The following sections describe using and setting
the configuration register boot field, and the tasks you must perform to modify the configuration register
boot field.
Bits 0 through 3 of the software configuration register form the boot field.
The factory default configuration register setting for systems and spares is 0x2102.
Note
When the boot field is set to either 0 or 1 (0-0-0-0 or 0-0-0-1), the system ignores any boot instructions
in the system configuration file and the following occurs:
•
•
•
You can enter the boot command only, or enter the command and include additional boot instructions,
such as the name of a file stored in flash memory, or a file that you specify for booting from a network
server. If you use the boot command without specifying a file or any other boot instructions, the system
boots from the default flash image (the first image in onboard flash memory). Otherwise, you can
instruct the system to boot from a specific flash image (using the boot system flash filename command).
You can also use the boot command to boot images stored in the Flash PC cards located in Flash PC card
slot 0 or slot 1 on the supervisor engine. If you set the boot field to any bit pattern other than 0 or 1, the
system uses the resulting number to form a filename for booting over the network.
You must set the boot field for the boot functions you require.
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
3-22
Software Configuration Register Bit Meaning (continued)
1
Hexadecimal
0x0800 to 0x1000 Console line speed (default is 9600 baud)
0x2000
0x4000
0x8000
Explanation of Boot Field (Configuration Register Bits 00 to 03)
Stays at the system bootstrap prompt
Boots the first system image in onboard flash memory
Specifies a default filename for booting over the network;
enables boot system commands that override the default filename
When the boot field is set to 0, you must boot the operating system manually by entering the boot
command to the system bootstrap program or ROM monitor.
When the boot field is set to 1, the system boots the first image in the onboard bootflash single
in-line memory module (SIMM).
When the entire boot field equals a value between 0-0-1-0 and 1-1-1-1, the router loads the system
image specified by boot system commands in the startup configuration file.
Chapter 3
Meaning
Boot default flash software if network boot fails
IP broadcasts do not have network numbers
Enable diagnostic messages and ignore NVRAM contents
Configuring the Router for the First Time
OL-4266-08