When operators finally get around to deploying next-generation set-top boxes,
they just might be running the Linux OS

Major cable operators have a vision. One where a beefed up, two-way network pumps loads of digital and interactive content to subscribers. The vision also includes a thick, multi-purpose advanced set-top that can receive and process all that valuable content in a flash. This next-gen set-top has the processing power of a PC, an open architecture to connect a host of compatible devices, and an interface that even a toddler can understand and operate.

It's nice to have a dream.

Now, the reality.

For the time being, the thin client set-tops that represent the majority of deployed boxes are the current playing field for interactive TV and other advanced services. Boxes like the ones in Motorola's DCT-2000 and Scientific-Atlanta's Explorer 2000 series weren't designed for interactive services or advanced processing in a two-way environment. Set-tops around the world are being developed with proprietary operating systems; software and middleware developers face the task of designing applications tailored to all of these divergent technical platforms.

In short, the advanced interactive services operators covet are a long time in coming without any unity across the hardware, software and middleware platforms.

"I'd say that a lack of standards across the board is a problem with interactive TV," says Adi Kishore, an analyst with researcher The Yankee Group. "We're looking at fairly lengthy and fairly in-depth integration requirements because systems are different, hardware is different, software is different."

So, with the current situation as it is, where innovative interactive applications aren't really developing because of this lack of standardization, a group of industry heavy-hitters are coalescing to bring some unity to the market. And they're unifying under the Linux operating system.

Back in June, at the National Show in Chicago, a group called the TV Linux Alliance was formally announced, with the stated intention of developing a standards-based Linux environment for the digital set-top market. Members of the Alliance cut across industry lines, but represent the major players trying to bring interactive services to operators: set-top makers Motorola and Pace Micro Technologies; middleware vendors Liberate and OpenTV; chipmakers Broadcom and Conexant; as well as many of the software and service companies that create products for the interactive platform.

In essence, these companies are betting that the next generation of interactive and digital services will only be developed through efforts at standardization, and that current proprietary operating systems are hindering development. That's why Microsoft and Scientific-Atlanta are notably absent from the Alliance—they maintain that their proprietary systems are robust and feature-rich enough to enable the development of these new advanced capabilities.

The market doesn't seem to want to wait, though.

"I think that some of the operating systems that have been in the set-tops for a long time—the proprietary ones—are considered to be a little bit more legacy. It's been a challenge to migrate those forward into the higher end set-top boxes, or even the mid-range ones and lower end ones that are still growing in terms of their features to accommodate more kinds of applications," explains Liberate Technologies' Fran Helms, the chairperson of the new TV Linux Alliance. "Some of those more proprietary systems have just kind of run out of steam."

So far, since the group's formation in June, technical representatives have been working to develop a baseline specification for a device driver API (application programming interface) which would serve as a "plug point" into a Linux operating system from which developers could work backward. The common API is the first logical step in developing a platform that can guarantee interoperability across its many layers.

"What we want to do is create a roadmap for all of the developers, all of the stakeholders who supply technology on the set-top box. What all of these vendors care about is a standardized Linux for the set-top box," says Helms. "The challenge with Linux is that it is so open that it is possible for many different implementations to be developed, unless there is some kind of commitment among the vendor community to standardize across a single API layer for set-top boxes."

Linux's "open" nature is well documented; the kernel source code is freely available to developers around the world, and the developer community has proven that by working together, it can more quickly create patches and fix bugs by community upgrades to the code. Linux has survived because it has continued to evolve in the highly competitive server market, and more recently as it migrates to more peripheral applications like the embedded device and server appliance markets.

"What the (TV Linux Alliance) API is intended to do long-term is to help create a standard API layer for Linux and the set-top box industry to help avoid fragmentation," says Cathleen Collett, a senior product manager with Linux systems provider Lineo Inc. She's also the Alliance's marketing chair.

"There's a perception out there that there are so many different distributions of Linux, that developers don't want to have to write 25 different flavors of one operating system. The API will help bridge that a little bit," Collett adds.

But all of this activity around the Linux operating environment begs the question, "What makes Linux so great?" While the immediate effects might not be terribly convincing, Alliance members support the Linux environment because of what it can do when advanced interactive services truly mature down the road.

For starters, Linux has proven to be stable, high performance and robust in the environments it's been applied in. With set-tops, like any other consumer device, it has to work and work well. It cannot consistently crash if bugs are discovered within the code. Any number of vendors need to be able to go in and fix that code, rather than waiting on a proprietary OS vendor to supply some sort of fix, which may or may not be a high priority for it. Linux has proven stable, and its open source nature makes the proprietary issue a moot one.

Another reason that Linux is such an attractive option for the set-top environment is its extensible nature, and its proven ability to support a broad and rapidly growing feature set. As box makers look to develop new thick client set-tops that can handle advanced data-rich applications, an OS that can adapt and accept this richer set of features is proving to be a necessity.

"As we look at the set-top roadmaps out there, set-tops are becoming much more complicated with next-generation versions," says Liberate's Helms. "Companies are talking about including features like PVR, incorporating hard drives, more sophisticated peripheral access—and Linux offers a really solid path to additional driver development to port those devices."

Along those same lines, the group has gravitated to Linux because of its proven ability to work in an Internet environment—an essential feature, as the applications coming down the road will certainly need gold standard Internet support to be truly maximized. Linux has inherent sophisticated networking built-in from the ground up, which should make it easier to layer on applications that require two-way capability.

However, even as the TV Linux Alliance is working to nail down a common Linux platform, Linux as an OS is still evolving from its traditional place in the corporate server arena down to the more feature-specific embedded device market—for consumer products like PDAs, cell phones, and of course, set-top boxes. Operating systems for consumer devices like these need to get slimmer and physically smaller, and must encompass fewer operating requirements. And the limited tasks you ask the OS to complete in an embedded environment become critical form factors in the design of any device system.

"Especially with video, you've got huge amounts of data that's coming through, so you've got to have real-time processing of all the data that's coming in," explains Daya Nadamuni, a technical software analyst with Gartner Dataquest. "Linux can probably do that, but it's going to take a while before it gets to that point."

When one talks about standardization of an interactive services platform, though, it's important to note that the standardization movement is working on two separate levels. At its lowest level, the TV Linux Alliance is working to standardize basement-level driver APIs. That work is complementary to other industry efforts at the content format level, like the Multimedia Home Platform (MHP) effort in Europe, and the slowly developing OCAP effort here in North America through CableLabs.

Companies in the space have already developed some initial products that incorporate Linux as an OS and interface with some of these newly-established content format standards. Notably, middleware developer OpenTV has created some satellite-based technology that works across these platforms, according to OpenTV's Chief Technical Officer Vincent Dureau. He says that the company has developed a satellite digital TV set-top box that uses Linux as an operating system, uses OpenTV software as middleware, and has MHP-compliant application software on top of that. It also incorporates the DeviceMosaic Web browser in the mix as well, providing a glimpse at what might be possible as the Linux OS and standards like MHP and OCAP begin to be integrated.

So, the Linux platform looks to be taking its initial shape. The TV Linux Alliance should go a long way in bringing standards to the fore so developers can get to work on tomorrow's interactive applications.

And part of that initial shape includes getting Linux into the mainstream set-top market, and that has already begun to happen in a few select instances. Recently, founding alliance member Motorola announced that it was making Linux an available OS option in its DCT-5000 family of advanced interactive digital set-top terminals. Available in Q1 of next year, Motorola will incorporate the Embeddix Digital Media core from Lineo (also a founding member of the Alliance) as an optional OS for its next-generation line of set-top boxes.

"I believe in giving as many choices as we can to operators...We'll now have multiple choices in terms of operating software," says Bernadette Vernon, director of strategic marketing for Motorola's DigiCable group. "It gives greater flexibility to the MSOs, and that's what we want to provide them."

For now, operators will need assurances that Linux can work as an OS in the interactive sphere. Even as Linux begins migrating to the set-top with a few select makers, the TV Linux Alliance is likely the group that can have the most impact on the growth of Linux in the market; if it can unify and standardize the platform, development of applications could snowball from there.

But in the immediate term, the Alliance has been working head-down to have an initial API delivered publicly by the end of the year, according to Alliance chairperson Helms. Look for the Alliance to meet its goal and announce something publicly by the end of the year, perhaps in time for this year's Western Cable Show. The group will likely announce the creative support from other non-founding Alliance members in time as well.

But for now, the TV Linux Alliance is working to take the first steps in getting the Linux snowball truly rolling.