Software Configuration Register - Cisco 7000 Series Hardware Installation And Maintenance Manual

Note
Flash Memory Write Protection
The Flash memory write-protection option protects the contents of Flash memory against accidental
erasure or reprogramming. The factory default, with a jumper installed on J2, is to allow
programming (writing) to Flash memory. To protect the contents, remove the jumper from J2. You
can later replace the jumper to enable Flash memory programming. The location of J2 is shown in
Figure 5-4.

Software Configuration Register

This section describes the software (virtual) configuration register that is used with the RP in a
system running Cisco Internetwork Operating System (Cisco IOS) Release 10.0 or later. Its
functions are identical to the hardware configuration register except the settings are changed through
the command line interface.
Following is the information included in this section:
•
Software configuration register settings
•
Explanation of boot field
•
Changing configuration register settings
•
Software configuration register bit meanings
•
Default boot filenames
•
Software configuration register settings for broadcast address destination
•
System console terminal baud-rate settings
•
Enabling booting from Flash
•
Copying to Flash
Software Configuration Register Settings
Settings for the 16-bit software configuration register are written into the NVRAM. Following are
some reasons for changing the software configuration register settings:
•
Force the system into the bootstrap program.
•
Select a boot source and default boot filename.
•
Enable or disable the Break function.
•
Control broadcast addresses.
•
Set the console terminal baud rate.
•
Load operating software from ROM.
•
Enable booting from a Trivial File Transfer Protocol (TFTP) server.
Table 5-4 lists the meaning of each of the software configuration memory bits, and Table 5-5 defines
the boot field.
Configuration register setting changes take effect when the system restarts.
Installing and Configuring Processor Modules
Maintenance 5-17