Requirements
The years I’ve spent making ShareTheNet work have taught me many lessons in how to make Linux perform in a very limited environment. After looking at the many “embedded Linux” products available for free or fee today, I felt that a simple, well explained, nuts-and-bolts example of an extremely small Linux toolkit would serve the developer community well. Therefore, I decided to risk even more hours of staring blankly at messages like the following while building the Embedded Linux Workshop:
Kernel panic: No init found. Try passing init= option to kernel.
The workshop doesn’t try to be all things to all people. As I mentioned earlier, I put it together primarily as a teaching aid, but I’ve been using it as the basis of all of my embedded Linux projects. Let’s look in a bit more detail at the requirements for the Embedded Linux Workshop:
It must run on a very common hardware platform, so anyone can use it.
It must be small enough so that someone trying to learn about embedded Linux software systems can understand it completely, with only a few days’ work.
The product of the Embedded Linux Workshop is a single 1.44MB floppy disk that can be used to boot a machine into the embedded application. This is almost certainly not what your final product will actually do, but it gives you a reasonable goal, allowing you to use hardware that’s easily available. If you were to use flash in this project, you probably would have to buy extra hardware before getting started.
It must be very well documented so that none of the pieces are mysterious. None of the binaries should be scraped from someone else’s package, unless complete source is available.
The build environment must not have “hidden steps.” That is, every piece of software that ends up on the floppy must be built from source using instructions that are available as part of the toolkit itself.
Every piece of the toolkit must be available under Open Source license.
The sample applications should be very simple, so they don’t detract from the main point—the code that gets the computer from power-off to running application.