The Reason Why There is No PS2 Emulator In FW 3.0

We do a little digging and uncover a few reasons.
By Dustin Rudzinski - August 21, 2009
Print    Email


Some of you may remember how we reported on rumors of the exact date and time Sony would be revealing PS3 Slim, cutting the price to $299, detailing firmware 3.0 (with a video showcase of it's features), and adding a new look and features for PSN (which was part of FW 3.0). We also mentioned that PSP GO would get a price cut, which was likely a mistaken interpretation of PSP GO getting added value to it's current price. However, that was UK only and only a week long promotion, so the price cut could still come. There is some evidence of this out there... We managed to get that information to you almost 2 weeks before the actual conference. Besides the one minor mistake, we hit the nail pretty much right on the head.

We had also heard before the conference that it was very likely that PS2 backwards compatibility would be included in the update, but that it was not a sure thing since our sources were not sure of how far along testing for the software emulator was. They did know it has been in testing for about a year now, however. After we did not hear anything about PS2 b/c in the firmware 3.0 update, we decided to try to find out exactly how far along it is and/or why Sony did not include it. This is what we found.

1. Most of the games need patching to make them run properly on PS3 hardware (bear in mind PS3 has no embedded EDRAM like PS2 did). Sony devs are saying it is not an easy task to make these patches.

2. PS2 is still selling good. Third party developers who are still releasing games on PS2 know that their games will sell better if PS2 is a separate console, as most people with a PS3 are going to primarily focus on buying PS3 games, which has a lot more games being released and therefore much more competition (even from the same publisher).

3. How to put games on PSN - Many PS2 games are discontinued right now, and it isn't easy for Sony to get copies of some games. Some games only have master copies available, which do not play on retail units and are not able to have the iso ripped from them. So, a retail disc must be re-authored in those cases. This is easier said than done, as many PS2 disc manufacturing systems have been taken down to make way for PS3 Blu-Ray manufacturing systems.

4. Memory card utility - Sony is not interested in producing many of them due to high cost of PS1/PS2 memory card slot. Apparently it's a low profit hassle that also (for the reasons listed in reason number 2) slows down the sales of third party PS2 games.

Also, one of our long time staff members who also happens to be a game developer (we call him cpiasminc) gave us a little more insight into why it is so difficult to emulate PS2 games:

Edit: Please note, to clarify, Cpiasminc made the following statement ONLY. The statements listed above come from another source who wishes to remain unidentified.

"I have my doubts as to whether it can ever really happen per se. This is a case where technical hurdles are every bit as large as the financial hurdles.

I mean, that eDRAM framebuffer and texture cache allowed you to have not only extremely high bandwidth, but also extremely low latency, and in turn meant that one render pass was extremely fast. Many times more so than any chip made today where the focus of the architecture is towards doing more work per pixel in a single pass (but in turn making the drawing of a single pixel many times slower and more complicated than it was on the GS). There is quite simply more framebuffer and texture bandwidth on the PS2 than the PS3 has. And even the eDRAM of something like Xenos doesn't really help here because the latency is higher and it's explicitly a transient state holding buffer, rather than a final output field. GS not only allowed you to work in eDRAM, but that was the main VRAM itself... it stored the front and back buffer as well as working textures in there. On current chips, the backbuffer and frontbuffer have to go through a resolve step and are always stored in main VRAM. All these sorts of things are exploited rather explicitly in the vast majority of PS2 games.

Even aside from the peculiarities of the GS, there are peculiarities of the interaction between the EE and GS. For instance, it's quite common to have the render loop be in a race condition against the GPU. We'll issue a display list to the GS which tells it to start processing from a vertex list... except that vertex list hasn't been filled at this point. Instead, the VU will go through the equivalent of a vertex shader and actually fill vertex data into that list while the GS is reading the stream. The timing is just so that the VU stays constantly a few clock cycles ahead of the GS. That kind of tight timing resolution and synchronicity is 100% impossible on all current architectures because there is just not that kind of relationship between the components, nor is there quite so much constant predictability to the operating performance of any component (i.e. nothing ever *always* takes up x # of cycles anymore). Also, synchronization primitives for modern bus architectures are actually very strict, so some of these types of things which were perfectly valid on a PS2 would actually not work at all because the bus would detect that a memory page is dirty and therefore wait for a cache write from the CPU before it does anything. This is of course done because it makes for a machine that is infinitely more stable, but that wasn't really the case for the PS2 which was more of a pure console. This sort of restriction means codependent read-write operations must wait for the CPU to finish -- a delay of many hundreds of thousands of clock cycles, while the PS2 only had to wait about 5 or 6 clock cycles."

So, all in all it just does not make much business sense for Sony to bother with PS2 backwards compatibility yet. They are focusing on making PS3 better right now anyway, trying to get things like cross game voice chat worked out and such. When they finally discontinue the PS2, we might see backwards compatibility included for PS3 then (though probably on a limited per-game basis). Until then, PS2 is still selling.

If you would like to learn more about the technical hurdles present with PS2 software emulation on PS3, including even more developer commentary from our very own cpiasminc, you may visit the thread in our forums. Sign up, post away. Who knows, you might even make a friend or two in the process.



View Comments (0)