A new generation of Linux-based entertainment appliances will deliver a variety of experiences and content into the home, car, and wireless handheld devices. Their medium may be streaming video, digital radio, interactive gaming, or some new category-smashing concept. Either way, the delivery channel (carrier) and the client devices share a set of core technical requirements: IP networking, WAN and local connectivity bridging, streaming-media support (CODECs and streaming file systems), security, power management, and support for industry-specific peripherals. To meet the required bill-of-materials (BOM) and the market price points for consumer goods, all of these features must come together in a small memory "footprint."

To achieve these goals, many manufacturers of these and other entertainment devices are building on Linux. They hope to leverage its "gold-standard" networking, robust architecture, and high security. Because it's an open-source operating system (OS), they also reduce their cost of goods sold (COGS).

Most people are only familiar with Linux in its enterprise or workstation forms. As a result, they're surprised to see the OS making its way into next-generation entertainment applications. According to developers, some key reasons for this move are Linux networking and the evolving, highly connected nature of next-generation consumer devices.

As a society, we've grown up with a set of distinct, mostly single-function entertainment appliances. They operated as either standalone devices or terminals for uni-directional content delivery. Examples include the car radio, CD player, VCR, and TV set, as well as portable handheld electronic games and tethered video games. Home audio/video equipment processed primarily analog (non-digital) content. For management functions, this equipment became increasingly microprocessor-controlled. Yet these devices still represented classic "toaster-type" embedded applications.

NOW VS. THEN To understand how stark the contrast is between the devices of the past and those of the present, look at the entertainment applications announced at this year's Consumer Electronics Show (CES). Also, check out those being delivered during the next 12 months. New products like the Sony Cocoon and the NEC AX10 Home Server emphasize rich feature sets and high-bandwidth connectivity to other "wired" (and wireless) devices in the home. This means that they have to manage content while supporting integrated connectivity over different physical media. To do this successfully, developers look to the embedded-Linux platform. With IP networking at its core, it boasts multiple options for routing and bridging among media and protocols:

• Physical connections: Ethernet; 802.11 (Wi-Fi); Bluetooth; Universal Serial Bus (USB); IEEE 1394 (Firewire/iLink); Infrared Data Association (IrDA); and various optical and analog audio/video cables
• Protocols and formats: TCP/IP; Microsoft networking; voice over IP (VoIP); Moving Picture Experts Group (MPEG); MP3; many proprietary interfaces; etc.

Linux was already known for bringing flexibility and reliability to enterprise servers, routers, and firewalls. Now, it imbues connected entertainment appliances with "consumer-grade" dependability and security in the increasingly wireless world.

Other motivators also attract entertainment-appliance developers to em-bedded Linux. For instance, it promises lower overall costs. While not all Linux-based CE solutions are royalty-free, the Linux kernel incurs no COGS impact. Moreover, the open nature of Linux is complemented by its full hardware and software toolboxes. This combined offering diminishes the need for expensive source-code purchases, proprietary add-on components, and costly consulting and services.

Developers also gain access to both an independent-software-vendor (ISV) ecosystem and developer communities. Embedded Linux can leverage the hundreds of independent software vendors that service the enterprise space, as well as software from the dozens of CE-oriented ISVs that now target Linux as their top-tier platform. The developer communities stem from the trend by which all types of consumer devices are being marketed as open platforms. Upon these platforms, both ISVs and individual developers build new applications, such as PalmOS. By leveraging the pre-existing Linux community with low-cost development tools, open-source Linux gives these communities an advantage. Examples include the growing communities around the Sharp Zaurus, as well as the hackers who port Linux to popular game systems.

A particularly interesting adoption phenomenon is the affinity that has grown between Linux, gamers, and game developers. For the past year, high-end desktop gamesmiths have been prototyping and shipping their wares on Linux. The open-source OS lets them squeeze every drop of performance out of available central-processing-unit (CPU) and multimedia devices. Unlike closed and proprietary Windows and MacOS platforms, Linux lets them reach out and optimize the underlying code that supports their digital-entertainment products.

The next logical step has been for those same developers to join the worldwide Linux hacker community. Together, they have "cracked" otherwise closed gaming platforms, like the X-Box and Sony PlayStation. They then port versions of Linux to those systems (see http://xbox-linux.sourceforge.net/ and http://playstation2-linux.com/). While targeting these devices with Linux has primarily been an exercise in hacker bravado, it also has succeeded in broadening the pool of game developers. In addition, it has established a grass-roots movement of after-market development.