Motorola's first Linux phone for the U.S. market will feature a single-core, ARM11-based chipset, according to a story at MobileBurn. If true, that could make it the first available phone to run an “open” OS of any kind on a single-processor architecture.

Traditionally, mobile phones based on “open” operating systems such as Linux, Symbian, and Windows Mobile have had a dual-processor architecture. The “baseband” processor — typically an ARM7 or other low-powered microcontroller — runs an RTOS (real-time operating system) such as VRTX that handles modem control and signal processing. The “applications” processor — typically an ARM9 — runs the complex open OS.

Dividing “control” and “data” functions between two separate processors is typical in networking applications of all kinds, from chassis-based telecom infrastructure equipment to set-top boxes. However, for low-cost, high-volume, mobile devices such as phones, a dual-processor architecture adds complexity, increases materials costs, and reduces battery life — the more so, since each processor needs its own memory and other subsystems.

For that reason, MontaVista, Motorola's longtime Linux supplier for phones, has been working for several years to add sufficient real-time determinism to its Mobilinux software stack to enable single-processor phone designs — data-oriented functions, such as voice processing and modem control, have critical timing requirements that Linux has traditionally fallen short of.

Meanwhile, VirtualLogix (formerly Jaluna), Trango, and FSMLabs/Infineon have taken a different approach, developing platform virtualization software and real-time overlays aimed at divvying up a mobile phone's physical resources between multiple operating systems. However, none of these approaches have been used in shipping products, as far as we know.

The MotoRizr Z6 — expected to ship by mid-year, but already being demonstrated at the CES show this week in Las Vegas — is probably based on a Freescale i.MX31. For one thing, Freescale spun out from Motorola, so the companies are closely related; additionally, the i.MX31 is among the first available SoCs (system-on-chip processors) based on an ARM11 core.

Other techie tidbits to be gleaned from MobileBurn's coverage include:

• Full QVGA (240×320) color display
• Reworked d-pad controller, compared to the earlier, non-Linux-based Z3
• A new user interface (UI), said to run “much faster” than Mot's earlier UIs for Linux phones

Motorola announced the MotoRizr Z6 on Jan. 8. The phone is expected to be the first of Motorola's phones for the mainstream U.S. market to be based on Linux.

The full two-page MobileBurn story includes a photo gallery, and can be found here.

 
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