Saw this recently.
5-second Linux boots on low-powered hardware.
They used multiple techniques to achieve such a fast boot. A couple of them were modifying the init process that runs at Linux startup time, and modifying a read-ahead process. The article says that they've submitted the read-ahead patch to Moblin.org - which could mean the speedup will get incorporated into Netbooks and other MIDs (Mobile Internet Devices) that use Moblin.
Vasudev Ram - Dancing Bison Enterprises.