Question about low-level ps2 programming

[Omega_Weapon]

Can anyone help me with these question?

1. what is rom0:UDNL used for? and how? what are parameters I need to put into?

2. what is rom0:OSDSYS used for? and how? what are parameters I need to put into? (there are using this fiile in Xenosaga and its parameter is "BootBrowser" or something like this but I did not know what is it used for?)

3. Is it possible to locate some part of execute file in 0x0 - 0xfffff memory space. If it is possible, why it is possible because as far as I know that is the memory space used for OS Kernel? (I saw some part of execute file of Action Replay locate at 0xc0000 or 0xd0000 I can't remember)

4. I noticed that the execute files of Action Replay or Code Breaker (another cheat game system) locates at the sector no. 12322 and system.cnf at the sector no. 12321 (there is a big dummy file in front of these files that size about 20-30MB), Is it important? why?

I am building a Action Replay Clone for my university project. That's why I asked all of these questions? and your answer would help me a lot.

Thanks

[Omega_Weapon]

No one answers me at all !!!!!!

WHYYYY?

Now, I have finished my project already. You guys do not need to give me the answer anymore. I have figured out all of these questions by myself already. (If someone helped me, it would have been easier)

Thanks for nothing. (I'm sorry if I say something you don't like)

#PS: Thanks to mr.brown (your project help me a lot) :-) Good job, man!
It is quite impossible to finish my project (Action Replay Clone) without his library.

[Arceles]

I cant answer the first, but i cant tell you why there is a big dummy file, the answer is because gameshark on loads an that lba, before of that lba the system.cnf will simply not load anything, this is only in gameshark, with chip there is no problem.