[nsp] cat6k, msfc2; boot-details

[Jochen Kaiser]

Hello,

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