ARM is trying to expand the reach of its low-power processors beyond phones and consumer electronic to mainstream computing. This week it took a critical step toward achieving that goal. ARM and Canonical announced that ARM’s new line of processors will fully support its free Linux-based desktop operating system Ubuntu.

ARM processors are embedded in everything from set-top boxes to digital TVs to car dashboards as well as a good deal of the smartphone and feature phones on the market—its low-power, highly efficient and cheap designs being optimal for devices with lighter processing needs. The traditional computing market, however, has been outside ARM’s purview, dominated instead by the X86 microprocessor architecture produced by Intel. While the X86 architecture has been the workhorse of desktop computing since its creation, a new hybrid computing market has begun to emerge centered on the ultra-mobile PC and the Netbook—inexpensive, wirelessly connected, browser-centric computers that have the same low-power demands of phones and consumer electronics. Meanwhile, ARM has been evolving its architecture to meet that industry’s more stringent processing requirements and is now perfectly positioned to target that hybrid computing space, said Kerry McGuire, ARM director of strategic software alliances.

“Our partners have always understood the importance of power,” McGuire said, referring to the device manufacturers that use the ARM platform. The ARM design incorporates functions such as graphics processing that would normally be separate components in a PC architecture, and unlike standard PC designs which supply constant power to all parts of the chip, the ARM platform powers down functions on the chipset when they aren’t needed, she said. “That saves orders of magnitude of power in those in-between stages,” she said.

Cracking the PC space, however, isn’t as simple a just sticking ARM chips into laptops, though. PCs and their operating systems are designed around the instruction sets of their processors, which has helped create a huge divide between the computer and the mobile device despite the supposed convergence between the two. Smartphone operating system such as RIM’s BlackBerry, Microsoft’s Windows OS, Android and Symbian have tailored their software to work with the ARM set, while PC operating systems such as Windows and the MAC OS are designed for the X86 instruction set. In order for ARM to find it way even into mobile PCs, it must find OS developers willing to optimize their software for ARM’s architecture.