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Re: 1-second kernel



On Sat, Dec 20, 2008 at 11:43 PM, Tim <ignored_mailbox yahoo com au> wrote:
> Tim:
>>> Five seconds is probably ambitious, but I still like how my old Amiga
>>> would COLD BOOT in 13 seconds, warm boot was 11 seconds.  That's from
>>> off, to fully working system.
>
> g:
>> also, think about how much memory you had and was it 8 bit. hard drives?
>
> No, not 8 bits.  ;-)  But there was an efficiency about it that isn't
> around these days:  You didn't make something multi-megabyte unless you
> had to.  You don't run a server unless you have to (right now, or at
> all).  Such as print servers if you don't need them, nor until you
> actually go to print.

Interesting discussion....
There are two places to pay critical attention to first:

  A.  hardware initialization.

For a system to boot all hardware has to be known in advance.
NO probes that time out for this and that...  SCSI timers are LONG...
No probe of USB this and that.

To that end building a kernel with "your" devices built in it
can help. Exclude any driver that you do not have hardware for.....
Keep a vanilla kitchen sink kernel everything kernel as a safety net.
Perhaps on a USB or LiveCD.

  B. Network timers.

Network timers are much longer than we all expect... Ensure that
all name servers and network knowledge that can be "hardwired" is. No DHCP no
discovery of name servers.   Snoop the net (dumb hub, second machine) and
watch for timeouts and other traffic you do not expect.

As others indicated most but not all services can be disabled....
and started later.   "sudo service cups start" can be run long after
you login.

For example X11 takes a lot longer to start than I expect.. in part because the
window manager desktop has all sorts of live buttons and widgets.   Clean up as
much as you can without X11 i.e. login on a simple text window... and
use 'startx'...

It is possible to use 'find' to discover all the files that have been
accessed (opened)
do an audit and find out why for each of them... all libs all programs...

Profile anything that might run prior to a shell prompt you can in isolation.

Simplify all that you can.

-- 
        NiftyFedora
        T o m   M i t c h e l l


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