[SunRescue] RE: Prom images for Sparcs :)

[Scott Newell]

>Blank space isn't the only issue you have to deal with.
>
>How much code is there that needs to read various info from the NVRAM
>and wouldn't know how to find it from the prom image?

Assume that you've got a working NVRAM with a dead battery.  It'll fail
checksum test, the MAC address and hostid will be wrong, and it'll go into
the monitor at powerup.  What's the bare minimum interaction required to
boot the OS from disk?  You could 'set-defaults', which would restore some
of the NVRAM.  I think then you could issue the boot command and be up and
running.  Do you even need to do a 'set-defaults'?  (It's been a while
since I've booted a dead NVRAM.)

I'd propose finding a way to add some fcode to the prom that would do just
that--restore the default NVRAM settings and force a boot.  Seems to me the
real trick is figuring out how to patch the existing code to call the new
stuff.  

I've never really messed with Forth, but it looks like there are some tools
built into the monitor that might help

For instance:

ok see startup
: startup
   sp@ saved-sp ! rp@ saved-rp ! hex warning on only forth also definitions
   (ffeb318c) if
      " disk0" (ffeb945c) (ffeb0c28) enable-interrupts (ffea85ac)
      0= if
         (ffeb9508) if
            show-post-results
         then  cr test-memory cr show-sbus cr
      then  (ffeb942c) (ffeb9474) mfg-switch? if
         reset
      then  (ffeb311c) auto-boot? eeprom-invalid 0= and (ffeb9508)
      0= and if
         (ffeb3180)
      then
   then
;


newell