Virtual Configuration Register Settings
5
Hardware Installation Guide
B-5
Hardware User’s Guide
B.1.2 Virtual Configuration Register Bit Meanings
The lowest four bits of the virtual configuration register (bits 3, 2, 1, and 0) form
the boot field. (See Table B-2.) The boot field specifies a number in binary. If you
set the boot field value to 0, you must boot the operating system manually by
entering the b command at the bootstrap prompt as follows:
>
b [tftp] flash filename
Definitions of the various b command options follow:
•
b—Boots the default system software from ROM
•
b flash—Boots the first file in Flash memory
•
b filename [host]—Netboots using TFTP
•
b flash [filename]—Boots the file (filename) from Flash memory
For more information about the b [tftp] flash filename command, refer to
Cabletron Systems’ CRM-DOC Set, a compilation of Cisco Systems
®
Router
Products Configuration and Reference Guides.
If you set the boot field value to a value of 0x2 through 0xF, and there is a valid
system boot command stored in the configuration file, then the CRBRIM-W/E
boots the system software as directed by that value. If you set the boot field to any
other bit pattern, the CRBRIM-W/E uses the resulting number to form a default
boot filename for netbooting. (See Table B-3.)
In the following example, the virtual configuration register is set to boot the
CRBRIM-W/E from Flash memory and to ignore Break at the next reboot of the
CRBRIM-W/E:
Router#
conf term
Enter configuration commands, one per line.
Edit with DELETE, CTRL/W, and CTRL/U; end with CTRL/Z
config-register 0x102
boot system flash
[filename]
^Z
Router#
The server creates a default boot filename as part of the automatic configuration
processes. To form the boot filename, the server starts with cisco and links the
octal equivalent of the boot field number, a dash, and the processor-type name.
Table B-3 lists the default boot filenames or actions for the processor.
