Custom embedded Linux images
The Yocto Project (Yocto) www.yoctoproject.org is a system that uses the Linux kernel and packages contributed from the OpenEmbedded software team. The Yocto team points out that its product is not a Linux distribution, but instead builds custom distributions; nevertheless, it can still can be extremely useful for creating a custom image.
The main contribution of the Yocto developers is a build system called BitBake. It fetches code from a variety of sources, can manage all kinds of compilation processes and can also take care of exporting the results in a ready-to-burn format.
A Yocto-based system consists of recipes and configuration files. Configuration files have a .conf suffix and contribute attributes which govern the build process. .BB files are called recipes, and are responsible for creating the actual components of the distribution; ultimately, running a recipe leads to the creation of a package.
Yocto differs from other embedded systems in that it divides its software stack into a set of layers. Images are created by combining layers, with Bitbake determining the compilation process. This approach might sound exotic, but it works well. For example, adding a new software stack such as Qt to an existing Yocto project can be accomplished by adding a reference to the file to the configuration.
