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Re: Debian boot system

Eyal Lotem <eyal@hyperroll.com> writes:

> Hello,
>   I've been pondering a new way to boot a Unix system,  and I was hoping to 
> hear your oppinion about it or if anyone has already attempted to implement 
> it.
>   The problem with current booting systems, is that the booting is 
> sequential, and each element of the boot process waits for the former 
> element, although most of those elements are not dependant on all former 
> elements.

sequential output is needed, so you nee to buffer all output from
processes and arrange them in a sequential order. Have fun getting
make to do this. Another way would be to put the source of the output
in front of eah line, but that would be a bit messy with "make -j100".

>   A simple solution to this problem,  is to describe the boot process with a 
> simple Makefile, which is more powerful in its description of dependencies, 
> and could even make management of the boot system simpler.   This Makefile 
> will also make the booting system easily parallel, using the -j feature of 
> GNU make.

Nice idea, so you probe for the number of cpus, add one and use that
as the argument for -j :)

>   The last advantage of this system, is the fact it should increase error 
> tolerance, increase the booting speed, and thus lower downtime.

Hmm, my alpha needs about 5 minutes to boot, 4 minutes until the
kernel gets started and another 45 second until init gets
started. After that it takes 14 seconds to mount the filesystems and
1 second for the rest. (that roughly how it feels).

Making that boot faster is pretty much useless. Most of the time is
wasted on parts not affected.

>   Was this system ever considered?  Should I create a draft Makefile to boot 
> the system?

I would love to see that, but it will be pretty hard.

1. you need the runlevels
2. you want to mount filesystems as soon as they are checked
3. you want to start demons as soon as their needed filesystems are
4. How do you know what filesystems are needed? Happy scanning.
   ( My squid need /mnt/raid to be present since /var/cache links to

I would realy like have xdm start as soon as /usr and /home are
present and have /mnt/raid still being checked in the
background. There is actaully no big reason not to allow users to
login just because the data grvae isn't present yet.
Only problem is that people might do cd /mnt/raid and not find what
they seek, but then again I'm the user and I will hear the fsck.

May the Source be with you.

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