Linux From Scratch

A few years ago, I posted a how-to on building your own bootable Linux flash disk. At the time, I was a little peeved about how much buying a pre-built Linux disk cost and how little it did, so I basically wrote out a recipe to pare down Slackware, swap in BusyBox, and arrive at a ~32MB Linux image.

Overall I've been quite pleased with the results-it's proven to be quite reliable. Unfortunately it's also frozen in time-it's very difficult to add or update system software, or even to update the kernel for that matter. So with that in mind, I started looking at the Linux From Scratch project to really do it right this time around. If you're curious, here's how to do it:

1. Get yourself an external hard drive, and start reading Linux From Scratch. Do everything on the external hard drive-you're effectively building yourself a development environment for later use.
   
2. Get yourself a boot device (Compact Flash card, another hard drive, etc.) that you'll use for your embedded project. Install your newly-minted Linux distribution on it.
3. Add features and functionality with Beyond Linux From Scratch.

And that's about it-of course I've leaving out steps like shrinking the final image and so on, but this is the general outline of what to do. If you're curious I can post the full recipe.

My end product came out quite nicely-although it's much larger than the original Linux image I made way back when (167 MB compared to 32 MB for a minimal install), it is a much better engineered product and has a lot more functionality. What you end up with is an image to be installed on your embedded device, plus that external hard drive of yours ends up being a portable development environment-you just chroot in from any Linux machine, compile your software, and it'll directly port to your embedded device.

All in all I can definitely recommend LFS as probably the best place to go for the DIY crowd. I'd have to say that it's also given me a deeper appreciation for the reasoning behind the GNU/Linux vs. Linux nomenclature debate. You really begin to realize as you progress through LFS and BLFS that the Linux kernel is really just one part of a much larger system that makes the complete OS. I don't know if I'm ready to adopt the GNU/Linux label just yet, but I do understand now where its proponents are coming from.