Linux in just a sec

by Andy Oram

Karim Yaghmour, author of

Building Embedded Linux Systems
,
told me he saw a demo of a Linux system that went from power-on to a GUI playing sound and displaying images in a little more than one
second.
This is, of course, a requirement for many consumer
electronic devices such as palmtops, and it was at the
CE Linux
forum a couple months ago that he saw the demo.



There were several tricks, some of them fairly simple, that permitted
the quick boot. First, the device ran the kernel from the FLASH card
where it resided instead of loading it into memory. Another trick was
to avoid the time-consuming countdown that a standard kernel uses to
figure out the approximate speed of the CPU. Since an embedded
developer knows what device the kernel is going to run on, it can be
hard-coded with the CPU speed.



There are certainly devices for which Linux is not suited, but it
proves pretty adaptable and is becoming mainstream in embedded
systems, as elsewhere.