Whats going on while a Psone game is executed?

[legion2000]

Hey Guys, im new here and im not into this "PS2 hightech stuff", i just have some questions which burned under my nails for too long.

Well here we go.
1. If i pop in a Psone game, the I/O processor is used as the Main procesor right? If so, what does the Emotion Engine at that time the Psone code ist running? Or is the EE used as the Main Processor?
What about the GS? is there a Psone Graphics Processor too or does the GS do the work?

2. Ive heard about this homebrew stuff. Its not possible just to put in a USB stick and copy data to memory card while in PS2 bios right?
but, is it possible to copy this homebrew codes on a USB stick and transfer it to the memory card with commercial software so that the code on the Memcard would be executed every time i switch on the PS2? i mean all without a modchip.

okay, thats all, i would apreciate some good answers,
bye

[J.F.]

Hey Guys, im new here and im not into this "PS2 hightech stuff", i just have some questions which burned under my nails for too long.

Well here we go.
1. If i pop in a Psone game, the I/O processor is used as the Main procesor right? If so, what does the Emotion Engine at that time the Psone code ist running? Or is the EE used as the Main Processor?
What about the GS? is there a Psone Graphics Processor too or does the GS do the work?

The IOP has all the PS1 hardware except for the video. The video in the PS1 was handled via DMA, so the EE intercepts that DMA stream and emulates the PS1 video. That's why the PS1 games look better on the PS2. The EE/GS is much better at rendering than the PS1 graphics chip. You'll see the difference in things like King's Field or Kileak the DNA Imperative where you had noticeable "fish-eye" effect on close walls.

2. Ive heard about this homebrew stuff. Its not possible just to put in a USB stick and copy data to memory card while in PS2 bios right?
but, is it possible to copy this homebrew codes on a USB stick and transfer it to the memory card with commercial software so that the code on the Memcard would be executed every time i switch on the PS2? i mean all without a modchip.

Right, not possible, and no, not possible. You CAN put a specially modified file on the memcard so that when you put in a certain PS1 disc, it runs a program on the card. That is called the Independence Day Exploit. If you do a search, you'll find many threads about it here. There is a file on ps2dev that also has many PS1 titles in it already to trigger the exploit. I think it's called Exploit Made Easy or something like that. Just search the forum now that I've given you something to search for. :)

[cory1492]

I never had any luck getting one of those multi title files to work, even when the games I tried were correctly listed ...

[J.F.]

There are reports that the exploit was fixed on recent PS2s. Up through 50K series seems to work from reports. I have a 30K1 which works fine. I use a PS1 football game disc since I can't stand sports games.

[legion2000]

Ah Thanks, so the GS is handling all the Video of ther Psone game right?
And the EE all the CPU power, okay thanks.

I saw some "commercial" USB sticks which come with special PS2 software, so I can transfer this Exploit to MC using this stick right?
And then i Install this exploit, what can I do with it? Is it possible to put some "self-booting" files on the Memcard so i dont have to put in a PS1 game at all? (I dont thinks so but give it a chance) :)

I dont see any useful things with this exploit, or is there some "media player" which is used with this exploit?

Okay thanks :)

[cory1492]

Youll need a ps1 game to use the exploit, or a mod with dev mode so you dont need the ps1 game (I think mods dev mode is based loosely on the exploit, but havent really looked into it)

ARmax Evo can be gotten with a memory stick (usb) which you can then compile your own game save for (or download one, Im sure Ive seen it) that contains the files that are needed for the exploit, then from the usb stick you can use ARMax to "restore" your custom game save which actually contains the exploit and whatever app/s that you have in there.

LaunchElf, keylauncher or ps2menu are good places to boot to.

Hrmm, I wonder if you can have more than one file to launch to and toggle them with different ps1 games. OK, now Im gonna go look for the exploit stuff myself.

exploit made easy - ps2dev
xploits for newbs - ps2scene - you will probably have to sign up for this one

[J.F.]

Ah Thanks, so the GS is handling all the Video of ther Psone game right? And the EE all the CPU power, okay thanks.

Not quite. The IOP is the PS1 CPU. The EE doesn't run any PS1 code at all.

The EE and the GS together draw the PS1 display. The EE converts PS1 graphics DMA into something the GS can handle.

Is it possible to put some "self-booting" files on the Memcard so i dont have to put in a PS1 game at all? (I dont thinks so but give it a chance) :)

Only if you get Sony to sign it for you. :D

Code can only run off the memcard automatically if it has the proper Sony encryption. We don't mess with that here.

[legion2000]

allright thanks, thats what i was looking for, thanks mate :)
So the EE sends teh code to GS...now it seems logical.
man this PS2 hardware is really exotic, pure madness but thats what I like about console hardware except the Xbox, boring Hardware.

Okay my question was answered, thanks again. Hmmm but what about this mysterious Sony encryption. You mean the Magic Gate? What does that stand for anyway and why does the PS2 support that but i cAnt "see" it anywhere? Whats the purpose?

:)

[J.F.]

To avoid piracy, Sony encrypts code which runs from the memory card. This is hardware encryption which isn't documented. It's also not needed for homebrew, so we don't bother with it here.

Yes, I like exotic console architectures as well. The finest example was the SEGA 32X CD.
32X:
2 SH2 CPUS
32bit VDP
PWM audio

CD:
MC68000 CPU
PCM audio processor
16bit GPU for scrolling and scaling
CD controller

Genesis:
MC68000 CPU
Z80 CPU
FM synthesizer
16bit/8bit VDP

All working together... an amazing feat. Which is why it'll be some time until a PS2 emulation of it is done. You can get a PS2 Genesis emulator - PGen. Any more than that will require some good assembly programming to get enough speed.

[legion2000]

But the fact that it is possible to run the code straight from the MC without needing a CD is amazing and worth dealing with. Or am I wrong? i thought of something like homebrew Minigames which can fit on a MC and you can play them straight from the Browser for example or a small Media or Mp3 player so you dont need to Disc swap....

Hmm about Exotic Hardware:
I think the most curious Konsole was the Sega saturn with its
3 CPU's
2GPU's
2 Sound Processors yehaw! :D
Man that was hard to program, but i also like the N64 Hardware... okay enough!

cu :)

[J.F.]

There's too much chance of piracy to mess with direct MC programs. People here will probably only ever do that if Sony releases a program to encrypt file for MC usage. Otherwise, forget about it.

The Saturn was very similar to the 32X.
2 SH2 CPUs clocked slightly faster than the ones in the 32X.
1 SH1 CPU to control the CD. However, it's hardcoded for specific CD routines which cannot be changed, so you cannot count this CPU as it might as well be a standard CD controller chip.
1 Yamaha 68000 for controlling the sound chip. The sound chip is more of a DSP than a CPU.
1 32bit VDP split by function into two chips. One chip did the 2D scrolling, scaling, and rotation, and the second chip did the texture mapping for 3D.

It's nowhere near as complex as the 32X/CD, but then it isn't a combination of 3 separate systems either. :)

The ORIGINAL Saturn prototype was just the SH1, the sound DSP, and the 2D VDP. When SEGA saw the PSX, they threw on the two SH2s, added the 68K to the sound, and added the 3D texture mapper.