"The Summit covered a wide range of topics from low level kernel details, to best community practices, but the ARM netbook support sessions were particularly interesting. At this UDS, the Ubuntu ARM developers set out to enable support for many ARM machines in a single distribution, a difficult task due to the lack of a standard firmware interface on ARM systems; a familiar problem to embedded developers. This report covers the solutions debated at UDS — including Kexec bootloaders and the flattened device tree — and the choices made for the next Ubuntu release.
"Ubuntu has supported the ARM architecture since the 2008 Intrepid Ibex (8.10) release, but the relative lack of consumer hardware has effectively made it interesting only to developers. During the Lucid cycle we can expect that to change as Canonical is working with ARM netbook OEMs to provide full support for the new devices that are widely anticipated to appear on the market in the new year.
"However, support for a wide range of ARM devices is complicated by the absence of any form of a firmware interface standard for ARM systems. The vast majority of ARM designs are embedded systems with no expectation that the end user will install their own software. General purpose ARM computers are historical rarities; the notable exceptions being the original Archimedes, and the Corel Netwinder. As such, unlike the x86 architecture where an IBM PC-type BIOS is mostly a given, device manufactures can (and do!) implement whatever firmware interface best meets their needs. Every device has a different method for booting the OS. Additionally, since firmware provides little if any information about the hardware, the kernel must be hard coded with device addresses and configuration information."
