Cisco Systems Cisco 12008 manual Default Boot Filenames Computed from Boot Field Bits

					Performing Other Configuration Tasks
Table 4-5	Default Boot Filenames Computed from Boot Field Bits
Action/File Name		Bit 3	Bit 2	Bit 1	Bit 0
Bootstrap mode		0	0	0	0
Default software		0	0	0	1
cisco2-grp or cisco2-prp		0	0	1	0
cisco3-grp or cisco3-prp		0	0	1	1
cisco4-grp or cisco4-prp		0	1	0	0
cisco5-grp or cisco5-prp		0	1	0	1
cisco6-grp or cisco6-prp		0	1	1	0
cisco7-grp or cisco7-prp		0	1	1	1
cisco10-grp or cisco10-prp		1	0	0	0
cisco11-grp or cisco11-prp		1	0	0	1
cisco12-grp or cisco12-prp		1	0	1	0
cisco13-grp or cisco13-prp		1	0	1	1
cisco14-grp or cisco14-prp		1	1	0	0
cisco15-grp or cisco15-prp		1	1	0	1
cisco16-grp or cisco16-prp		1	1	1	0
cisco17-grp or cisco17-prp		1	1	1	1

The significance of other important bits in the software configuration register is described in the following paragraphs.

Bit 8 of the software configuration register controls the console Break function key. Setting bit 8 (the factory default) causes the system to ignore the console Break key. Conversely, clearing bit 8 causes the system to interpret activation of the Break key as a command, forcing the system into the ROM monitor mode (rommon>) and halting normal system operation. Regardless of the setting of the break enable bit in the software configuration register, activation of the Break key causes a return to the ROM monitor prompt during approximately the first 5 seconds of booting.

Observing System Startup and Performing a Basic Configuration 4-41