This has been floating around for a couple of weeks now, but it is a good read.
At the Linux Plumbers Conference a few weeks back, two Linux developers employed by Intel demonstrated an Eee PC with GNU/Linux which had been modified to boot, to a full graphical environment, in five seconds:
They had to hold up the EEE PC for the audience, since the time required to finish booting was less than the time needed for the projector to sync.
The LWN writeup contains many details of their talk and includes quite a few interesting tidbits. (X runs a C preprocessor and compiler every time it boots? Seriously?) The two engineers conclude that the culprit for poor boot time is scores of components providing power and flexibility which only a few people use but everyone has to pay for, like the following:
[Ubuntu] spends 12 seconds running modprobe running a shell running modprobe, which ends up loading a single module. The tool for adding license-restricted drivers takes 2.5 seconds— on a system with no restricted drivers needed.
This is also a good example of the kind of innovation that simply cannot happen on proprietary systems. Information about the entire Linux/GNU/services/X stack is freely available and modifiable, and one consequence of this is that it is very easy to build on the progress of others. It then becomes strikingly clear that all of us is smarter than any one of us, and substantially more creative.
Moreover, the experience obtained here is actually being used to help improve future versions of our operating systems, rather than being confined to the backwater of hacks that appear on Slashdot and are never heard from again.