[nsp] cat6k, msfc2; boot-details

Greenhalgh, John JGreenhalgh at newskies.com
Tue Aug 19 01:30:58 EDT 2003

Hi Jochen,

Concerning your problem that it loads the boot loader instead of the IOS,
are you sure your ata-disk is visible from the MSFC? We had huge problems
getting them to work and in the end we gave up. To test that the ATA disk is
working from MSFC do the following:

In CatOs, copy a file on the disk:

copy config disk0:test

And then in MSFC IOS do

copy sup-slot0:test bootflash:test
copy sup-disk0:test bootflash:test

Note that doing dir sup-slot0: or dir sup-disk0: never works, even if the
card is visible.

If one of the above works, then you know you can see the disk. If not, then
you need to try upgrading Supervisor rommon and supervisor code, although it
got so messy we gave up and are currently attempting to field upgrade MSFC
bootflash from 16Mb to 32Mb (which is free (in the UK)).

Cisco do not recommend loading IOS from a flash card or disk because the
MSFC effectively views it as a network drive, like a TFTP server.

Let me know how you get on - we're on a mission to try and understand how
these things boot as well, and I agree there are surprisingly few docs on


-----Original Message-----
From: Jochen Kaiser [mailto:Jochen.Kaiser at rrze.uni-erlangen.de]
Sent: 17 August 2003 14:38
To: cisco-nsp at puck.nether.net
Subject: [nsp] cat6k, msfc2; boot-details


After reading some documents and doing some practise, I try to dive
in a more deeply into the boot process of the cat6k and msfc2
in hybrid mode. (After having to use disaster recovery via
xmodem last week, I'd appreciate any answers helping understand
the procedure)

I did not find a doc on CCO which 'really' makes it clear.

I understand, that there are 4 mechanisms on the msfc2:

1. config register
2. BOOT variable (???)
3. BOOTLDR for helper image
4. 'boot system' statement in nvram config

I assume, that there are 3 image types:

1. ROM Monitor		-> loaded when all fails

2. a c6msfc2-boot image -> loaded when other image fails

   (that's what I've read, but I watched, that it is booted
    each time, also when a loadable normal image is reachable
    on bootflash)

3. a c6msfc2 		-> regular image 

Now we have different situations:

a) an image is defined in nvram config 'boot system'
   and the image is on the bootflash
   -> image loads
   my q:
   (is it correct, that the boot image isn't booted when 
    the main image is reachable?)

b) an image is defined in nvram and residing on an ata-disk 
   and there is an 'boot' image on bootflash
   -> since image cannot be found, the boot-image boots
   -> it reads the nvram-config and boots second image on ata-disk

   my q:
   - is the position of the boot image of any relevance?
     I heard, that it is important, that it is the 1st 
     file on the bootflash. Is this right?
   - does this just happen, when the config register has
     the appropriate value of 0x2000 ?

c) no image defined, config register 0x102
   and boot image is on bootflash
   -> ????

   my q:
   - What happens?

d) an image is defined in the 'BOOT'-variable
   -> ????
    my q: 
    - what is the sense of the boot-variable? 
      (Is it just a status variable for the nvram boot system command?)
    - how is it set when I don't want to use 'write mem'?
    - what happens, if it is not set? is it fully replacable
      by the 'boot system' residing in nvram?

tia & greetings,

Jochen Kaiser

Dipl. Inf. Jochen Kaiser, GPG 0x3C93A870, phone +49 9131 85-28681
Network Administration  mailto:jochen.kaiser at rrze.uni-erlangen.de
Regionales Rechenzentrum Universitaet Erlangen-Nuernberg, Germany
Homepage and PublicKey: http://ipv6.rrze.uni-erlangen.de/~unrz111 
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