How do I do a COLD Reboot on FreeBSD?

[Billy Newsom]

Oliver Leitner wrote:
> I am not completely sure...
> 
> but from what i know bout a COLD Reboot:
> 
> just unplug the power cable.
> 
> that exactly does what a COLD Reboot does.
> 
Yep, you are techically right, but of course, I asked how to do this from the 
operating system, in this case FreeBSD.  Many "diagnostic disks" and ROM 
burning floppy disks do a cold reset from software, just as some examples. 
This code is available, but I need to do this remotely, from 3000 miles away, 
or tell someone how to do it over the phone, or write it on a napkin glued to 
the monitor (aka "sticky note") for a clueless user who happens to be near 
the box, etc.

And personally, I would rather not disengage the power cord.

The target "look and feel" will be to type "rebootme" and see the video card 
BIOS screen, followed by memory counting, etc. and the POST.  Right now, 
typing reboot eventually just crashes the system after the CPU's are halted. 
  I will probably need to hack the kernel source to do the disk syncing and 
other stuff which shutdown/reboot do.

Billy

> On Monday 31 January 2005 15:31, Billy Newsom wrote:
> 
>>I need to do a cold restart.  I've looked through a lot of docs, and I
>>can't seem to find this out.  The computer I am working with seems to no
>>longer enjoy a warm reboot (like "shutdown -r now" or "reboot") but I'm
>>pretty sure it will do cold reboots fine.  Is there a port, or is the
>>shutdown command hackable for this, or what?
>>
>>I remember many computers in bygone years which had this problem. It was
>>pretty common back in the 90's it seems like.  Computers would reboot and
>>act weird using CTRL-ALT-DELETE, but work fine when powered off and on.
>>
>>The computer I've got actually fails a memory test during the warm reboot.
>>This freezes it.  I have to power cycle the machine.  And then, the
>>computer performs a warm restart, bypassing its memory checks!  One more
>>power cycle laster, it will boot normally.  If I don't do this last reboot,
>>the FreeBSD boot loader or the beginning of the kernel boot crashes very
>>early.  It's stable otherwise on a cold reboot.
>>
>>Thanks,
>>Billy