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Re: ping reply without OS

>    Having read that the interface card is capable to reply to icmp echo
>  requests, my next question should be this: Why does does the card assume 
>  that we are using the internet protocols? (On a side note, this does
>  no good to those who ping the machine and conclude that everything is well
>  with the ip layer of the halted machine, when in fact it should be dead.) 

I believe this is incorrect. Ping replies do depend on the kernel
being alive, but a shutdown (as opposed to reboot) will take the
system to single user mode, where the kernel is still running.
However, you cannot use any other services because the appropriate
daemons are not running to handle them.

>     My real complain is when I read "System halted", my assumption has
>  always been that the cpu has executed the x86 HALT instruction . Why 
>  not, it consumes a lot less enery in this state.

Huh? Linux will issue HLT instructions when not doing anything else.
However, HLT does not really halt the machine, like when you're finished
using it, but only until the next interrupt. Yes, HLT does lower
power consumption. On a Cyrix 6x86 CPU, with suspend on HLT enabled,
power consumption changes from 24W to 0.3W. This is enough to hear
a difference in CPU fan speed. (I am running this hardware here.)


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