Yocto is an organization consisting of many vendors to provide tools and infrastructure which enables customers to build their own Linux distribution from source code. Since an embedded Linux system consists of mainly open source software, the source code is directly fetched from the individual projects. Building the whole stack from source allows higher configurability and reproducability, however it comes with the cost of some configure effort and build time.
Namely the Yocto project provide infrastructure such as
There are other open source tools which are developed under the umbrella of Yocto, see the Internal Projects page of Yocto.
Toradex makes use of the main infrastructure of Yocto, namely:
We provide our BSP as an own OpenEmbedded layer called meta-toradex, available at http://git.toradex.com. We do not make use of the Poky reference distribution by default due to its limited desktop capabilities. Instead, we opted to use the Yocto compatible Ångström distribution with a LXDE desktop environment. This allows Toradex to provide a similar user experience to Windows CE.
Toradex also recommends to use Qt to build appealing user interfaces, which are possible to run with or without Desktop environment (see How to set up Qt Creator to cross compile for embedded Linux). With some configuration effort it is also possible to use the Yocto reference distribution Sato, if preferred.