Datasheet

59
OL-17436-01
Additional Configuration and Maintenance Tasks
Additional Configuration and Maintenance Tasks
This section contains information on the following additional configuration, maintenance, and upgrade
tasks:
• Understanding the Cisco IOS Software Configuration Register, page 59
• Understanding the Cisco IOS XR Software Configuration Register, page 63
• Using Flash Disks in the PRP, page 67
• Removing and Installing a Compact Flash Disk, page 71
• Removing and Installing a Hard Disk Drive, page 72
• Recovering a Lost Password For IOS, page 74
• Recovering Password for IOS XR, page 76
• Upgrading PRP Memory, page 78
Understanding the Cisco IOS Software Configuration Register
Configuring the software configuration register is described in the following sections:
• Description of the Software Configuration Register, page 59
• Boot Field Settings, page 61
• Configuring the Software Configuration Register, page 61
• Bits in the Software Configuration Register, page 62
Description of the Software Configuration Register
The software configuration register is a 16-bit register in NVRAM that you use to define specific system
parameters. You can set or change the contents of this register to accomplish the following tasks:
• Define the source for the default Cisco IOS software. You can specify any of the following:
– Flash memory card inserted in PCMCIA slot 0
– TFTP server on the network
– Flash memory SIMM (NVRAM) on the RP
– Boot image stored within the operating environment, which you access by using an appropriate
form of the boot command entered at the ROM monitor prompt (
rommon>)
• Define a default boot filename.
• Enable or disable the Break function.
• Control broadcast addresses.
• Set the console terminal baud rate.
• Recover a lost password.
• Force an automatic boot using a boot image.
When you first power on the router, a boot image called the RP ROM monitor is executed, resulting
in the display of the ROM monitor prompt (
Rommon>). At this prompt, you have access to a limited
set of commands that enable you to set values in the software configuration register and to perform
a number of other tasks.