forums.ps2dev.org

NeoCloud · Joined: 22 May 2004 Posts: 6

I have two ideas that I would like to do.
I would like to know if these ideas have already been done.

1st: I want to be a able to get a hdd (not neccarily an official sony ps2 hdd) and store memcard info on it, so I can access this info from games. I would also like to have linux on it at the same time. I know about the Official linux kit, which isn't bad. But sony says that the entire drive will be formatted for linux and you couldn't use it for anything else. Is this true? Can you not even have multiple partitions?

2nd: I want a better ps1 emulator. Is it possible to write a new one for the ps2 and replace "PlayStation(R) Driver 1.11" with say "MyPS1 Driver 2.0" (I know this would probably require writing a whole new bios or something). Or even a ps1 emulator for linux on the ps2 hdd.
When I say better I mean, it is able to display at higher resolutions and enhance the textures and graphics more. Like epsxe with the various graphics and sound plugins, you have some very nice result, but sometimes certain parts of a game don't work right and you have to tweek the settings. And for epsxe there are no plugin/setting combonations that work for all games. If a better ps emulator for ps2 where made, it would be easier to get everything working nicely without having to mess with setting for each game.

dagamer34 · Joined: 24 Jan 2004 Posts: 35

NeoCloud · Joined: 22 May 2004 Posts: 6

Somewhere I got the idea that the ps2 does emulate the ps1. I assummed that the ps2 hardware was different from the ps1. Is the ps2 cpu, and other hardware backward compatible with the ps1, similar to how the pentium2 instruction set is a superset of the pentium1 instruction set? And in fact the ps2 does not emulate the p1?

Also you said "you would need to know the complete ins-and-outs of a system, something almost all homebrewers can do and few professionals have the time and resources to do" ?

pixel · Joined: 30 Jan 2004 Posts: 791

The PS1 is mainly composed of (please correct me if I'm wrong, and I sure will do mistakes there)

-) A main mips r3000 CPU with 2MB of memory
-) a cop0 (System Control Coproccessor)
-) a cop2, which is the GTE, the Geometry Transformation Engine
-) a GPU, linked to the main CPU with a DMA bus
-) some various IO things, like the CD, MC, SPU, etc, controlled by the main cpu.

For the PS2, it is composed of:

-) A main mips r5900 CPU, called the emotion engine, EE, with 32MB of memory.
-) A secondary "IO" processor, a mips r3000 CPU, with 4MB of memory, called IOP
-) Several VUs processors, all linked to the ee, and the first one is linked to the IOP, as its cop2.
-) basically, all the above hardware, linked together using the same basic scheme, with various enhancements.

Now, when booting, the PS2 bios is copied to the EE and the IOP, which will quickly detects the current running processor, and jump to its dedicated location. Then, if the detected CD is a PS1 game, the IOP will act as the PS1 r3000 processor, and all the linked hardware around will more or less act as the basic PS1 architecture.

That's the basic idea of "how the PS2 runs PS1 games", minus all the various mistakes I could have done.
_________________
pixel: A mischievous magical spirit associated with screen displays. The computer industry has frequently borrowed from mythology. Witness the sprites in computer graphics, the demons in artificial intelligence and the trolls in the marketing department.

KaylaKaze · Joined: 05 May 2004 Posts: 75 Location: NC, USA

I'm working on a HDD/MC transfer program. As for actually making the PS2 think it's saving to a memvard but actually saving to the HD, it's iffy bu may be possible. If I manage to get the program do all I want though, you won't notice much difference between direct HD write and MC write.