How Xbox 360 Works

Microsoft released two versions of the Xbox 360 in November 2005: the Xbox 360 Premium Package and Xbox 360 Core System. Since then, the lineup has undergone some changes. The Premium Package is now known simply as the Xbox 360 console. A new Elite system hit store shelves in April 2007. Microsoft announced another new system, the Xbox 360 Arcade, in October 2007.

The Core System is "plug and play" -- in addition to the console, it includes a wired controller and an AV cable. The Xbox 360 comes with a wireless controller, an HD AV cable, an Ethernet connectivity cable, a headset and a removable 20-GB hard drive. Initially, it also included a DVD remote, but this is no longer available as part of the package.

The Xbox 360 Elite is similar to the main Xbox 360, with a black case, matching wireless controller and headset. It also includes a larger 120-GB hard drive and an HDMI cable.

To combat Nintendo's surprise powerhouse, the Wii, Microsoft announced the Xbox 360 Arcade in October 2007. Aimed at casual gamers, the console will come with between three and five Xbox LIVE Arcade games and will probably include "Pac-Man," "Uno" and "Luxor 2."

Microsoft has also prepared subtle variations of the console for marketing tie-ins. To commemorate the release of "The Simpsons Movie," Microsoft created a run of 100 limited-edition Simpsons Xbox 360s, which were given away in promotions. Fans of Bungie's "Halo" game series can purchase the "Halo 3" limited edition Xbox 360, which comes in "Spartan green and gold" and features a matching controller.

On the next page we will see what makes the Xbox 360 tick -- the central processing unit, or CPU.

As with any computer, the CPU is the heart of the Xbox 360. Microsoft has outfitted the 360 with a 165-million transistor, multi-core processor running three 3.2-GHz PowerPC cores.

Each core on the chip functions as a separate processor. Recently, hardware manufacturers have started combining several cores, or processors, onto one chip. This is a multi-core processor. Multi-core processors offer a combination of tremendous computing capabilities and efficient power consumption. They split

heavy work loads over multiple powerful processors rather than giving all the work to one super-powerful processor.

The other interesting thing to note about the Xbox 360 CPU is that each core is capable of processing two threads simultaneously. Think of a thread as a set of instructions for a program's job. The core processes these instructions and does the heavy lifting to get the job done. A conventional processor can run a single execution thread. Because the Xbox 360 cores can each handle two threads at a time, the 360 CPU is the equivalent of having six conventional processors in one machine.

What this means when you are playing video games is that the Xbox 360 can dedicate one core entirely to producing sound, while another may run the game's collision and physics engine. The system may allocate an entire processor just to rendering hi-def graphics. It's really up to the game developers how the system's considerable resources are used. With a multi-core processor, the system is powerful enough to pull off the computational demands needed for an amazing gaming experience without even breaking a sweat.

The graphics processor unit, or GPU, is responsible for the heavy-lifting for the console's beautiful, high-resolution images. Read more about it on the next page.

Another powerful asset in the Xbox 360 is the Graphics Processor Unit (GPU). The Xbox 360 boasts the new, custom-built 500-MHz ATI Graphics Processor card with 10 MB of embedded DRAM. While the 500-MHZ graphics processor is powerful, and 10 MB of DRAM provides ample memory for the GPU to do its job, the most innovative thing about this card is that it is built on unified shader architecture.

Shaders are computer programs that determine the final look of what you see on the screen when you're looking at computer animation. Shaders take rendered 3-D objects built on polygons (the building blocks of 3-D animation) and make them look more realistic. There are two types of shaders: pixel shaders and vertex shaders.

Pixel shaders alter the lighting, color and surface of each pixel. This in turn affects the overall color, texture and shape of 3-D objects built from these pixels. Pixel shaders help "smooth out" 3-D objects, giving them a more organic texture. To learn more about pixel shaders, see nVidia: Pixel Shaders.

Vertex shaders work by manipulating an object's position in 3-D space. "Vertex" refers to the intersection of two coordinates in space. The machine maps the position of an animated object in 3-D space by giving it a value. These values are the x, y and z coordinates. By manipulating these variables, a vertex shader creates realistic animation and special effects such as "morphing." To read more about vertex shaders, see What are Gouraud shading and texture mapping in 3-D video games?

In real-time graphics, like the kind you see in video games, shaders work with the graphics processor. The shaders make billions of computations every second to perform their specific tasks. These computations are performed in steps through a series of computational components. Think of an assembly line. In the world of hardware, these assembly lines are called pipelines.

Traditionally, pixel shaders and vertex shaders have dedicated pipelines because each one has very specific and differing needs. As we learned before, the new ATI graphics card in the Xbox 360 has unified shader architecture. What that means is that now, both shader types share the same pipelines. ATI figured out a way at the hardware level to address the needs of both types of shaders using the same pipeline.

The apparent advantage of sharing pipelines is to add more assembly lines, making computation that much faster. ATI claims that this unified shader architecture allows for 48 billion shader operations per second. The Xbox 360 is the first device to use this type of architecture.

On the next page, we'll learn about how the Xbox 360 fits in with your home entertainment system.

Input/Output

The Xbox 360 supports up to four wireless controllers at once. It also has three USB 2.0 jacks, two in the front and one in the back that can be used to plug in wired controllers for play or wireless controllers when they need to be charged. The USB jacks can also be used to connect devices like digital cameras, MP3 players and computer keyboards to the 360 (but the keyboard can only be used for text entry, not game play).

Online

The Xbox 360 has an Ethernet port to hook up to a broadband connection, as well as a slot for a WiFi card. The 360 is WiFi-ready "out of the box" and the bundle includes a connectivity Ethernet cable.

TV Connections

The Xbox 360 comes standard with both composite and component video connections to hook up to a TV. There are also optional connections for S-Video and VGA, and the console supports some SCART-type adapters used in Europe. The Xbox 360 Core System includes a standard-definition AV cable, while the other Xbox 360 bundles come with an AV HD cable and a media remote.

Audio

The Xbox 360 has multi-channel surround sound that supports 256 channels of 48 KHz, 16-bit digital audio. The 32-bit audio processing is handled by the CPU. One of the most talked about new audio features of the Xbox 360 is customizable soundtracks. No matter what video game you are playing, you can play or stream your music during game play.

Removable Hard Drive and Storage

The original Xbox was quite innovative in that it had an 8-GB hard drive built into the console. The 360 takes the hard-drive concept one step further: The Xbox 360 includes a removable 20-GB hard drive, and the Xbox 360 Elite has a removable 120-GB hard drive. The Xbox 360 also supports up to two 64-MB memory cards at one time.

The Disc Drive

In keeping with the idea that the Xbox 360 is a full media center, it sports a 12x dual-layer DVD-ROM that can read DVD-Video, DVD-ROM, DVD-R/RW, DVD+R/RW, CD-DA, CD-ROM, CD-R, CD-RW, WMA CD, MP3 CD and JPEG Photo CD. You can buy an external HD-DVD player for the Xbox 360. The 360 does not, however, support Blu-ray.

Cooling

The original Xbox took a lot of criticism for how large it was. The cooling system that kept the Xbox's rather hefty processor cool was the single greatest factor that contributed to the console's robust size. Microsoft changed all this for the Xbox 360.

In order to fit all that hardware into the stylish and slim form factor of the Xbox 360, Microsoft devised a cooling system that combines a small, vacuum-sealed, liquid-cooled system with fans to maintain a comfortable temperature inside the 360. The system regulates the temperature of the cores and adjusts the flow of liquid and fan speed accordingly. Additionally, the cooling system monitors the core's workload: If one or more cores are not needed for the job at hand (for instance, if you are using the Xbox 360 to watch a DVD), then the unused cores are automatically turned off.

Other Accessories

There are dozens of accessories on the market for the Xbox 360, including headsets, wireless controllers, cooling systems, rechargeable batteries and more. You can play compatible Xbox 360 games on your Windows computer with the Wireless Gaming Receiver for Windows. The Live Vision Camera allows players to create an in-game version of themselves in select games. The Xbox 360 Wireless Racing Wheel is a force-feedback steering wheel controller with standard gamepad buttons and floor-mounted accelerator and brake pedals. The Messenger Kit attaches to Xbox 360 controllers and features a keyboard to message other players.

In the next section, we'll take a look at the Xbox 360 controller and how it has evolved from the original Xbox controller.

The design for the Xbox 360 controller is based largely on the one used for the original Xbox -- the Controller S.

The most noticeable difference in the Xbox 360 controllers from those for the original Xbox is that most of them are wireless. Microsoft created a proprietary technology to deal with some of the latency and bandwidth issues that can be a problem for some wireless controllers. The Xbox 360 can support up to four wireless controllers at one time.

The wireless controller comes with all Xbox 360 bundles except for the Core system, which includes a wired controller with a nine-foot cable. Everything else about the design is the same. Of course, wireless controllers are available separately if you choose to upgrade.

The new Xbox 360 wireless controllers can be powered by either a pair of traditional AA batteries or a rechargeable battery pack. The battery pack can be "flash charged" in a charger or "trickle charged" via a USB connection to the console, and it alerts the user when its charge is running low.

The Xbox 360 controller has a Guide button in the center of its face that provides a new functionality. This button is divided into four quadrants that light up to provide gamers with different types of information during game play. (Incidentally, the "ring of light" power button on the console also provides this function.) For instance, during a split screen multiplayer match, a particular quadrant will light up to indicate to a player which part of the screen he or she is playing on at that time. The Guide button can also light up to let a player know he has received a message from another gamer. In this case, when the user pushes the button, he or she visits the Xbox dashboard (the equivalent of a PC's desktop). The dashboard provides access to features like messaging friends, downloading content, voice chat and customizing soundtracks, all while staying in the game. The controller has a standard headphone jack on the back so that the user can plug in a headset for voice communication during game play. Some wireless headsets will also work with the Xbox 360.

The new Xbox 360 controller has the same basic familiar button layout as the Controller S except that a few of the auxiliary buttons have been moved. The "back" and "start" buttons have been moved to a more central position on the face of the controller, and the "white" and "black" buttons have been removed and replaced with two new shoulder buttons that are positioned over the analog triggers on the back of the controller.

One of the great features of Xbox 360 is its ability to let players compete against one another online. Learn about Xbox LIVE on the next page.

Xbox LIVE is an online subscription service that allows Xbox gamers to play video games together and download additional game content using the Internet. Once online, gamers can play one another over the Internet and talk to each other in real-time using the headset (included in the bundle). Xbox LIVE has created a huge online community of gamers challenging one another worldwide. The Xbox 360 will also usher in the next generation of online game play and online community with the new, revamped Xbox LIVE.

The new Xbox LIVE has enhanced matchmaking and feedback systems as well as voice chat and video conferencing. It has a new, more seamless interface and is a generally more robust system for communicating during online gaming. Xbox LIVE on the 360 is divided into two services: Xbox LIVE Silver and Xbox LIVE Gold.

Xbox LIVE Silver is a free service that ships with all Xbox 360s and allows any Xbox 360 user with a broadband connection to get online and create a gamer tag as well as a new ID type called a gamer card. The gamer card is a profile that displays a gamer's interests, skill level, competitiveness and gaming accomplishments. In addition, gamers can use Xbox LIVE Silver to chat, download content and play certain games. Xbox LIVE Silver allows gamers to access most of the features of Xbox LIVE. The one key feature missing from the free service is the ability to play multiplayer games online.

In order to play in multiplayer matches online, you must upgrade to the subscription service known as Xbox LIVE Gold. The Gold service has all the functionality of Silver plus the ability to play multiplayer games. Additionally, Xbox LIVE Gold has exclusive content, tournaments and events.

For more information on this service, see How Xbox LIVE Works.

Serious gamers know the Xbox 360 has a great slate of games available for it. Learn more about Xbox 360 games on the next page.

As history has shown time and again, the latest and greatest console is nothing without great games. Microsoft has set out to create a series of blockbuster titles in-house for the Xbox 360 as well as make deals with as many third-party developers as possible. Game developers are attracted to the prospect of creating games on such a powerful canvas, and in the years to come they will find new ways to build games that push the potential of the Xbox 360.

One game franchise more than any other has defined the success of the Xbox and Xbox 360: "Halo." Microsoft acquired game developer Bungie Studios in 2000 to bring the game to the original Xbox. The game took off and spawned a sequel. Then, on September 25, 2007, came "Halo 3." In 12 days, it had already surpassed the biggest-selling game in 2007, "Wii Play," selling 3.3 million copies and pushing the Xbox 360 ahead of the Wii in numbers of consoles sold for the month [source: Casamassina]. Microsoft even released a special "Halo"-themed Xbox 360 console for hard-core fans.

The game even seems to have affected the motion picture industry. Ticket sales for the October 5, 2007, weekend only totaled $80 million, a 27 percent decrease from the same weekend the year before [source: Brodesser-Akner, Claude]. Some movie executives blame Bungie and Microsoft for stealing their sales.

Below is a list of games that released with the Xbox 360. For a complete list of current and upcoming games, check out Xbox.com Games.

For more information on the Xbox 360 and related topics, check out the links on the next page.