Poky uses the OpenEmbedded build system and, as such, uses the BitBake tool, a task scheduler written in Python which is forked from Gentoo's Portage tool. You can think of BitBake as the make utility in Yocto. It will parse the configuration and recipe metadata, schedule a task list, and run through it.
BitBake is also the command-line interface to Yocto.
Poky and BitBake are two of the open source projects used by Yocto:
- The Poky project is maintained by the Yocto community. You can download Poky from its Git repository at http://git.yoctoproject.org/cgit/cgit.cgi/poky/.
- Development discussions can be followed and contributed to by visiting the development mailing list at https://lists.yoctoproject.org/listinfo/poky.
- Poky development takes place in the master branch. Before merging submitted patches into the master, maintainers test them in the master-next branch.
- Stable Yocto releases have their own branch. Yocto 2.4 is maintained in the rocko branch, and Yocto releases are tagged in that branch.
- BitBake, on the other hand, is maintained by both the Yocto and OpenEmbedded communities, as the tool is used by both. BitBake can be downloaded from its Git repository at http://git.openembedded.org/bitbake/.
- Development discussions can be followed and contributed to by visiting the development mailing list at http://lists.openembedded.org/mailman/listinfo/bitbake-devel.
- Bitbake also uses master and master-next in the same way, but then creates a new branch per release, for example 1.32, with tags going into the corresponding release branch.
The Poky distribution only supports virtualized QEMU machines for the following architectures:
- ARM (qemuarm, qemuarm64)
- x86 (qemux86)
- x86-64 (qemux86-64)
- PowerPC (qemuppc)
- MIPS (qemumips, qemumips64)
Apart from these, it also supports some reference hardware BSPs, representative of the architectures just listed. These are:
- Texas Instruments BeagleBone (beaglebone)
- Freescale MPC8315E-RDB (mpc8315e-rdb)
- Intel x86-based PCs and devices (genericx86 and genericx86-64)
- Ubiquiti Networks EdgeRouter Lite (edgerouter)
To develop on different hardware, you will need to complement Poky with hardware-specific Yocto layers. This will be covered later on.