So the poor field lost to value determines how the writer will boot
that consists of four binary bits which are either set on or off a value of 0 means Romanova to a value
of 1 means boot into our boot.
In the old days all today means boot using the first operating system in Flash.
Setting it to two or a great number such as F or e.
In other words anything from 2 to F means normal boot.
So this value is set to 2 or greater means normal boot.
So in other words enables default booting from flash memory you can override that by using the boot
system commands in the running config of a router.
So on a radio you could use the boot system command to specify that a different operating system is
used as an example.
So the router would boot from a TFT server as an example.
So in other words on the router you could use a command such as pooched system and tell the router to
boot its operating system off a TFT piece of war and peace over as an example rather than puting the
operating system from flash when I wrote it boots up it goes through a series of steps which include
loading the Cisco Iowa software from Flash or if specified from somewhere else such as a nifty piece
of into the ram of the router.
The router will also load the configuration stored in startup config and apply that and use it as the
running config.
So here are the steps that it takes when booting up the first thing it does is perform the power on
self test or post.
This is a series of hardware tests that verify that all the components of a Cisco Rodolf functional
during the test.
The rod also determines which hardware is present.
This executes from microcode that is stored in the system from.
So he has a router and his APC are going to do an immediate reboot on the router
so you can see the rod is booting up and then is loading the operating system.
Now its going to do a power on self-test but thats not very clear on this router.
So what Im going to do is show you the power on self tests on a Cisco switch so I'll do a reboot on
the Cisco switch.
And you can see the 29 50 bootloader is being used.
It's now loading the operating system from flash.
And what I'd like to show you here is notice the power on self tests that are shown on the switch so
you can see clearly back power on self tests have been passed on the switch.
And then the switch boots up and the interfaces come up.
So scrolling back noticed power on self-test power on self-test can see the operating system is loaded
and then the switches ready to start.
Now something similar is taking place on a router.
We just don't see it as clearly in the output.
But here's the output.
When I reloaded the router you can see run monitors initialized the program loads are taking place.
The operating system is being decompressed and loaded.
So the first step on a router is to perform a power on self-test.
The router then loads and runs the bootstrap code which is used to perform subsequent events such as
locating the Cecka Iowa software loading it into RAM and running it off to the Cisco Iowas software
is loaded and running the bootstrap code is not used until the next time the rod he's reloaded will
power cycled on this 1041 router.
We can see that the bootstrap code is loading the operating system.
And here we can see which version of operating system has been loaded into RAM.