The Yocto Project is an project that intends to provide an OpenSource build system, based on top of Poky and Open Embedded, that enables developers to create their own linux distribution specific to their environment.
To ease this even further, the Yocto Project offers some templates of different sizes (tiny to fullblown), which the developer can adapt (extend or shrink) by the simple means of editing some configuration files. Internally Yocto uses a tool called "bitbake" to perform builds. The instructions for the build are called "recipes". This is similar to Gentoo's ebuild system, so adding new packages or modifying packages is quite easy. When bitbake is then run, it takes care of fetching the sources, compiling, packaging and creating the image, but also provides the developer with a toolchain for cross compilation and a Software Developer Kit (SDK) tailored to his own distribution. Depending on the configuration, the created image can then be deployed directly onto the target hardware or emulated via qemu.
Unfortunately Yocto currently leaves out the bootloader part of the system, "as this should be provided by the board vendor".
A quick overview of Yocto's internal flow can be found here: Yocto Flow (Getting Started Guide)
Yocto intends to work closely with the upstream projects - e.g. updating the kernel at least once every 6 months for regular releases, but also providing the possibility to run the latest git version of the kernel - and tries to be software and vendor agnostic - thus you can e.g. choose which package manager format you intend to use in your embedded linux distribution (deb, rpm, ipkg).
Yocto has also an excellent integration into the Eclipse IDE, and allows you to do most of the necessary steps from within Eclipse.
Here are various FAQs about the Yocto project:
- Robert Day's FAQ based on question's he's gotten about the Yocto Project
- this has a few technical items
- Poky is one sample distribution provided by the Yocto Project, and so understanding how Poky is built and be customized is a good start to understanding Yocto.
- this has overview stuff, not of a technical nature (reading it will likely just confuse you)
Finally, here is my own (Tim Bird's) introduction and overview:
- The Linux Foundation announced the Yocto Project in October, 2010 at
- Version 1.0 was released on April 6, 2011.
- Version 1.1 was released on 21 Oct 2011 and was presented during the ELCE 2011
- Yocto is sponsored by the Linux Foundation.
- Yocto technology derives from Poky Linux, which was a branch of Open Embedded
- Developing Embedded Linux Devices Using the Yocto Project and What's New in 1.1 Talk by David Steward (Intel) at ELCE 2011 Presentations