According to Samuel Hornus\[Isobel\]:
>
>BTW, what does the boot message `root on wd0a dumps on wd0b'
>means ? (`dumps on'...)
>

If your machine panics it can write a kernel core dump into the dump
device.  Dumps on wd0b means that the kernel core dump will be written
to /dev/wd0b (normally your swap partition), when the machine reboots
a program called savecore will check /dev/wd0b for a kernel core dump
and write this into /var/crash if one exists and you have enough
room.  This can be handy if you are debugging a kernel problem and
want to know why the kernel panic'ed.  Note that your dump device
needs to be at least as big as your physical memory otherwise the
kernel crash dump will not be written to it (I think).

-- 
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Brett Lymn, Computer Systems Administrator, BAE SYSTEMS
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