Configuring The Software Configuration Register - Cisco 7604 Configuration Manual

Chapter 3 Configuring the Router for the First Time
The ROM monitor has these features:
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Configuring the Software Configuration Register

The router uses a 16-bit software configuration register, which allows you to set specific system
parameters. Settings for the software configuration register are written into NVRAM.
Following are some reasons for changing the software configuration register settings:
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Table 3-2
boot field.
The recommended configuration register setting is 0x2102. If you configure a setting that leaves break
Caution
enabled and you send a break sequence over a console connection, the router drops into ROMMON.
Table 3-2
Bit Number
00 to 03
06
07
08
09
10
OL-4266-08
Power-on confidence test
Hardware initialization
Boot capability (manual boot and autoboot)
Debug utility and crash analysis
Monitor call interface (EMT calls—the ROM monitor provides information and some functionality
to the running software images through EMT calls)
File system (the ROM monitor knows the simple file system and supports the newly developed file
system through the dynamic linked file system library [MONLIB])
Exception handling
To select a boot source and default boot filename.
To enable or disable the Break function.
To control broadcast addresses.
To set the console terminal baud rate.
To load operating software from flash memory.
To recover a lost password.
To allow you to manually boot the system using the boot command at the bootstrap program prompt.
To force an automatic boot from the system bootstrap software (boot image) or from a default system
image in onboard flash memory, and read any boot system commands that are stored in the
configuration file in NVRAM.
lists the meaning of each of the software configuration memory bits, and
Software Configuration Register Bit Meaning
1
Hexadecimal
0x0000 to 0x000F Boot field (see
0x0040
0x0080
0x0100
0x0200
0x0400
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
Modifying the Supervisor Engine Startup Configuration
Meaning
Table 3-3)
Causes system software to ignore NVRAM contents
2
OEM bit enabled
Break disabled
Use secondary bootstrap
Internet Protocol (IP) broadcast with all zeros
Table 3-3 defines the
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