What is it?
Linux on mobile devices has followed a similar path to desktop Linux. This time last year, six different consortia and companies were working on Linux for mobile phones, and far from offering any prospect of convergence, their approaches were actually taking them further apart.
Big suppliers are beginning to consolidate around certain initiatives. In April, Intel announced that it wanted to offer Linux as an alternative operating system for its next generation of mobile internet devices, which are due to arrive in 2008.
Analyst firm Gartner said, "Although the consumer is unlikely to care what operating system is running on the mobile internet device, the device cannot succeed without attracting a development community to create a robust platform at an affordable price point." Intel would therefore be setting out to create a "strong Linux ecosystem".
In June, the Linux Phone Standards consortium announced a key part of its 1.0 specification. The consortium includes companies such as Trolltech and MontaVista, the supplier of the version of Linux used by phone maker Motorola, among many others.
Motorola in turn is a member of the LiMo Foundation, along with NEC, Panasonic, Samsung, DoCoMo and Vodafone, which aims to establish a set of interfaces and standard reference components to increase the number of third-party developers for mobile devices.
Motorola has also joined the Eclipse Foundation as a strategic developer member, and it is helping to kick off an Eclipse Tools for Mobile Linux project to provide the extensible frameworks and tools for developing C++ applications for mobile devices.
Where did it originate?
Linus Torvalds first asked for help with his free operating system kernel in 1991. Since then it has grown from a small number of C files to about 40Mbytes of source code under the GNU General Public Licence. Embedded Linux started to take off in 2003.
What's it for?
Embedded Linux uses the Linux kernel with a limited set of software utilities.
The creators of the Debian Linux distribution described the process of creating its embedded version, Emdebian: "This is essentially standard Debian optimised for size translations are split into dedicated packages rather than forcing all translations on to all users, documentation and examples and similar extraneous guff is left out, and library dependencies are reduced as far as possible."
Many of the Linux distributions have an embedded counterpart for example, Red Hat's Embedded Linux, MontaVista's Hard Hat Linux, Embedded Gentoo, and a forthcoming version of Ubuntu for embedded and mobile devices, which will be tailored for Intel's mobile internet device.
What makes it special?
The new generation of phones such as Motorola's RIZR Z6 will be able to run Linux on a single-processor architecture. Previous phones had to have a dual processor, with one running a real-time operating system while the other acted as an applications processor. Montavista's Mobilinux now supports single-processor architectures.
How difficult is it to master?
If you already have Linux skills, you can learn Embedded Linux on a three-day course. Developers need to learn how to get the maximum performance from limited resources, writing closer to the hardware than they will be used to.
What's coming up?