Internal Affairs

In the nearly 30 years between the launch of the Fairchild Channel F and the Microsoft Xbox 360, console owners didn't have to worry about hardware compatibility issues. You bought a system, looked for the name of your system on the software box, and hoped that the manufacturer would support the system long enough to justify your purchase.

There have been a few re-designs along the way, almost all of which resulted in a smaller (i.e. cheaper to manufacture) console such as the Atari 2600jr, the top-loading NES, the Genesis 3, the PS One and the slimline PS2. While there were a few software issues, for the most part none of these re-designs fundamentally changed the system's architecture.

Not so with the latest generation of consoles, which now include multiple SKUs from both Microsoft and Sony.

On the Xbox 360 side, you have the Core, the Pro, and the Elite, with the Arcade bundle soon to replace the Core. Hardware variations range from wired to wireless controllers, component A/V or HDMI output, and the inclusion or exclusion of a hard drive. The latter is not only important for consumers who wish to download content such as games and movies, but for those who wish to continue playing their original Xbox software. Since backwards compatibility is achieved through software emulation, original Xbox games will only work on 360 consoles with a hard drive.

To date, PS3 hardware variations have eliminated flash memory card readers, Wi-Fi, the PS2 Emotion Engine chip, and the chrome trim, but have never sacrificed the hard drive. In fact, since the system uses a standard 2.5" SATA drive, tech-savvy consumers can even upgrade it on their own.

Three separate changes have been made with the new 40GB PS3.

First is the loss of SACD playback. If you had to do a Google search for "SACD" just now, it isn't surprising that this is probably the least noticeable change. SACD is a high-fidelity audio optical disc format that differs from standard audio CDs. Most SACDs are hybrids, compatible with existing players, but you won't be able to play the SACD part of the disc in your 40GB PS3.

The second change is the elimination of two of the console's four USB ports. Unlike the Xbox 360, all PlayStation 3 models have wireless controllers that only require the USB ports for charging. PS3 owners can also use the ports for keyboards and headsets, for charging Warhawk's Bluetooth headset, and for attaching the PS One/PS2 memory card reader.

Other peripherals that have required USB ports in the past include Singstar karaoke microphones, Buzz quiz controllers, and the Eye Toy. No PS2 game ever required the use of more than the two standard USB ports, however, and it is hard to imagine a situation where all four of the PS3's USB ports would be needed simultaneously. But even if such an unlikely situation arose, USB hubs are cheap and widely available.

The third change, the elimination of the Graphics Synthesizer chip, is currently the most talked-about, as it prevents PS2 games from being played on the new system.

It is important to understand that backwards compatibility has been made possible through different combinations of hardware and software.

"The 20GB and 60GB PS3 models launched in Japan and the US were equipped with both the PS2 Emotion Engine and Graphics Synthesizer chips and we could therefore guarantee over 90 per cent backwards compatibility for PS2 titles," SCEE's Nick Sharples told GamesIndustry.biz

"The 60GB model launched in Europe, like the 80GB model launched simultaneously in the US, contains only a modified version of the Graphics Synthesizer chip and not the complete PS2 Emotion Engine chip."

The European 60GB and North American 80GB consoles therefore used a combination of software and hardware to deliver PS2 backwards compatibility.

The new 40GB model, announced for Europe and Japan, is not equipped with any of the semi-conductors from the PS2. Backwards compatibility would therefore need to be achieved by software emulation alone, and sources say that some design features of the GS chip cannot be easily emulated.

So why do PS One titles continue to work?

None of the PS3 consoles have ever included the CPU or GPU used in the original PlayStation. Backwards compatibility with those titles has always been done through software emulation, and thus it has remained no matter how many times the PS3 hardware has been changed. Although it could be eliminated, there would be no cost savings in doing so.

Sharples concedes that it would be hypothetically possible to provide support for individual PS2 games if there was enough of a demand for it. Sony could, for example, support individual titles such as God of War in future software updates...either free of charge, or for a small fee via the PlayStation Network.

Consider also that the storage capacity of a Blu-ray disc, approximately 25GB for a single-layer, is about the same capacity as five DVDs. It would theoretically be possible to fit the data from multiple PS2 games, and the emulation software needed to run them, on a single PS3 disc. Backwards compatibility problem solved!

For the moment, however, Sony has decided not to take a piecemeal approach to backwards compatibility. It is an all or nothing proposition...nothing, in the case of the new 40GB model.

"The sheer number of PS2 titles available, together with the increased complexity of using a software-only solution for each and every title means that ensuring accurate software emulation would be technically challenging, time consuming, and costly," Sony has said in a statement.

Sony has pointed out that US gamers who consider backwards compatibility to be important are still able to purchase the existing 80GB or 60GB units...at least, while supplies last.

Even so, there is likely to be more than a little confusion over the four different PS3 consoles that have been, or soon will be, available in the US market. One can imagine a situation where the same PS2 title will work, may or may not work, or definitely won't work on a PlayStation 3 due to the different hardware configurations.

As long as hardware manufacturers continue to add expensive new technology to their consoles, and remove it in an attempt to re-position themselves in the market, the recent phenomena of multiple SKUs is likely to continue.