bootstraps...

not sure if odom and the rest still mention this but booting or rebooting is derived from the idea of bootstraps, or more accurately, pulling oneself up by the bootstraps... the safest way to remember what configuration settings do is to look at the boot field...  the boot field is the last four bits (all the way to the right) that comprise a number in hex normally 0x2  or ox2102 which means to boot from the config file in flash if possible...

if the last number is 0 boot to rommon, if it's 1 boot software contained in rom...

0x2142 means bypass start (config in nvram) and is mostly used in password recovery...

use show version to see the current config-register setting, ie,

Configuration register is 0x2102 (will be 0x2142 at next reload)

show run and show start do NOT show the register setting but will show manually input boot system configuration...


r2620_01#sh run
Building configuration...

Current configuration : 2049 bytes
!
! Last configuration change at 12:51:27 UTC Sat Dec 17 2011
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname r2620_01
!
boot-start-marker
boot system tftp myass 255.255.255.255

my college friends and i used to refer to throwing up, as booting