It's just XP Pro in legobrick form, really... how long it
takes to boot depends on what you include. The less that's
there the less time it takes to boot, generally. That's
not always the case, as leaving some things out slows it
down, but generally less is faster.
Try leaving out network support, USB, etc if you don't need them.
Remove all unnecesary services.
Base your image on Minlogon.
On P4-2400@800MHz FSB with 2x400 DDR memory I was able to make our
application start in 15 seconds. If I disable our storage driver then it is
14 seconds.
What do you mean by 'least components'? What size was your
final image? I can't say I've tested mine for boot time,
but I do remember when I was trimming the image down that
when I removed some components that boot time went up,
presumably because the unit was looking for something that
wasn't there.
Ah, well you can get a smaller image by removing the
devices you don't need before you start resolving
dependencies, and your image may still do what you want
even without a lot of the components the dependency check
brings in. Working out which ones is usually a matter of
trial and error, however.