Checksum error at bootup

[Joe Smith]

In article <2293 at brchh104.bnr.ca> dynasys!hbmc!jessea at rutgers.edu (Jesse W. Asher) writes:
>I've had this happen to me a couple of times so I thought I'd better find
>out what's causing it.  I've got a Sparcstaton 1+ running 4.1 and a couple
>of times when I've tried to boot the system from the PROM monitor prompt,
>I've gotten an error message like: 
>        checksun xxxxxxxxx != xxxxxxxxxx 
>        Trying to boot anyway.
>At least one time after I got this message, I then got a "memory out of
>alignment" or some such error and it refused to boot. 

The message means that someone overwrote /boot and did not run
mdec/installboot.

The boot PROM does not know how to read Unix filesystem directories,
therefore it cannot locate the /boot file by name.  Instead, it reads in
the first block of the disk, knowing that the executable code there has
pointers to the blocks of /boot imbedded in it.  The installboot program
(found in /usr/kvm/mdec in recent SunOS releases) calculates and stores
these pointers.

Anytime the /boot file is overwritten (deliberatly or accidently), you
must re-run installboot.  Otherwise the PROM may load random garbage and
die the next time you try to reboot.

Joe Smith (408)922-6220 | SMTP: jms at tardis.tymnet.com or jms at gemini.tymnet.com
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