fast-booting Debian

[Fabio Fabbri]

> http://www.hoeg.org/blog/2005/07/27/fast-booting-debian/
Nooo, you stole my idea! I had to patent it :)

I'm thinking on a way to implement parallelized boot since the last 
release of my live distro (http://www.llgp.org). I, too, think it could 
be implemented modifying "/etc/init.d/rc".

I think your hack could be improved modifying the "startup" function. 
Actually it looks like:

startup() {
   case "$1" in
	*.sh)
		$debug sh "$@"
		;;
	*)
		$debug "$@"
		;;
   esac
}

but it may become:

startup() {
   DEPENDS=$(getDependencies $1);
   for i in $DEPENDS; do
     isStarted $i
   done
   case "$1" in
	*.sh)
		$debug sh "$@"
		;;
	*)
		$debug "$@"
		;;
   esac
   if [ $? -eq 0 ]
     then
       setStarted $1
     else
       # The script failed, do something!
   fi
}

Where getDependencies is something that writes on the standard output 
all the scripts needed by another script.

isStarted is something that asks to a daemon if a startup script was 
started. It doesn't return until the script is started. The daemon must 
be started before.

setStarted is something that tell to the daemon that this script is 
started and all scripts waiting on isStarted can go on.


Another way to implement a parallelized boot could be replacing 
/etc/init.d/rc with a c program that builds the Directed Acyclic Graph 
of the startup scripts, then it can try to start them with the right 
order. Could it be a better solution? Can we find other better solutions?



I'm going to begin a little project for my live distro (and perhaps 
other distros), and I would call it "bootster". I hope to add this kind 
of initscript, but I will try also to build a good initial ram disk that 
can find hardware and boot the system as fast as possible.


Regards
Fabio