how does ps2 recognize cdrs?

[Jejunum]

btw mods dont ban me for this i am not advocating piracy;

Perhaps not highly technical but all the same its an interesting question
i just wanna know how the ps2 knows that a cd is a cdr
also how do the anti copy schemes work ?

ive seen articles regarding pc but not on ps2/ps1.

thnx guys

mods lock this thread if it offends u...

 

[Pinski]

Hmm yes interesting, *bump*

 

[DaLeroy]

<< btw mods dont ban me for this i am not advocating piracy;

Perhaps not highly technical but all the same its an interesting question
i just wanna know how the ps2 knows that a cd is a cdr
also how do the anti copy schemes work ?

ive seen articles regarding pc but not on ps2/ps1.

thnx guys

mods lock this thread if it offends u... >>



Original Playstation cd's have got data written on parts of the cd that normal writers can't access/write to. This area contains the boot information. When a copied game is put in, the playstation checks for the boot info from this section, can't find it and tells you it's not a game/legit disc etc.

Mod chips simply supply this information to the machine, so that it doesn't check the copy for the boot information.

Hope this helps

 

[Mday]

"pre-groove"

 

[Buzzman151]

Are there any CDRW's that can acually replicate this by "going the exra distance" Or what about duplicating machines? I know some of them have higher quality cd burners.

 

[Buzzman151]

anybody?

 

[0x7a69]

actually there's more to the ps1 copy protection than that. otherwise something like clonecd would prolly be able to copy them. their solution (which i consider to be almost as clever as the gamecube's protection of simply making cdrs not fit) is to write some number of sectors as all 0s. (it's been a while since i've read up on this, so some things may not be 100% but it will give you an idea). since data cds are written with parity checks to the sectors, a sector containing all 0s fails the check and burners will automatically "correct" the data. the only way around this is with a hacked up burner or using a mod chip.

 

[Noriaki]

<< actually there's more to the ps1 copy protection than that. otherwise something like clonecd would prolly be able to copy them. their solution (which i consider to be almost as clever as the gamecube's protection of simply making cdrs not fit) is to write some number of sectors as all 0s. (it's been a while since i've read up on this, so some things may not be 100% but it will give you an idea). since data cds are written with parity checks to the sectors, a sector containing all 0s fails the check and burners will automatically "correct" the data. the only way around this is with a hacked up burner or using a mod chip. >>

No because there are copy programs that will do bit by bit copying ignoring parity and error checking.




<< Are there any CDRW's that can acually replicate this by "going the exra distance" Or what about duplicating machines? I know some of them have higher quality cd burners. >>

It's not an issue of quality.

Sony makes playstation CDRoms that can read closer to the center of the disc than standard CD roms.

For exmaple (made up numbers), a regular CDRom has a center area of 20mm diamater. That 20mm area is just nothing, it's the mounting area for the motor. No data can be written to or read from that area.

You could pay many thousands of dollars for a proffesional CD stamper like Microsoft uses to Cut Windows XP CDs, but it still won't write data to that 20mm circle that CD readers can't read from.


Now, on the playstation CDroms, Sony decided this 20mm circle would only be 18 or 19mm instead of 20. Then they have a slight area where no standard CD Recording or Reading equipment can Write or Read.

Then since your CDRW is not physically capable of writing to this area since on a normal CD it doesn't exist.

Sony uses this bit to encode boot data, if it's missing it goes to the CD play screen rather than playing the game. It's not so much how it tells a real game from a CDRW game.
It's how it tells a game from anything else, so it knows whether to run the game, or go to the Music Player program.


I'm not 100% sure if this is accurate, but that's the best description I've managed to gather.

 

[Barnaby W. Füi]

finally noriaki clears up the babble, he is the <correct> one here

the ONLY (read: ONLY) burners that will burn to that area of a disc are the ones that sony uses/rents/sells/licenses to other companies for making psx discs.

 

[0x7a69]

yeah, i stand corrected. apparently the bad block/sector stuff is just a neverending rumor. sorry about that...

 

[Jejunum]

cool thnx guys; i can rest easy at night now!

 

[CTho9305]

hmmm.... someone needs to find a buffer over-run error for the CD-player so you can run "arbitrary code" (a game launcher ) and boot (legal) backup copies without modding the playstation

on that note... anyone know where the CD-player software is stored physically?

 

[Jejunum]

<< hmmm.... someone needs to find a buffer over-run error for the CD-player so you can run "arbitrary code" (a game launcher ) and boot (legal) backup copies without modding the playstation >>



is it actaully possible; or are u just speculating? that would be "wicked keen" if it was possible!

 

[CTho9305]

well, there are billions of ways to do it for MS outlook, and various MS applications, but I doubt that the playstation's cd player has bugs like that, unfortunately . doesn't mean it is bug free... maybe someone could find a way

 

[Maniac9127]

There's a way to fool the playstation into thinking it has a real playstation game using a demo disk. I forget the way it works, but it goes something like: start the playstation with the demo disk, and when the screen blacks out to load (after the startup screen) the game switch to your copied CD and supposedly it'll load. I know it works because I saw my cousin's play games like this, but I'm not sure of the exact way to do it.

 

[Jejunum]

on a sorta seperate note what does this mean for the linux kit?

how will one use regular cdroms when in linux (grrr if u cant). maybe by installing the linux kit its like an external mod chip by sony? Also are u booting linux off the cd or the included 40 gig hd?

 

[CTho9305]

i think you can write a disc that boots, and after that you dont need special CDs any more.

 

[Jerboy]

<< btw mods dont ban me for this i am not advocating piracy;

Perhaps not highly technical but all the same its an interesting question
i just wanna know how the ps2 knows that a cd is a cdr
also how do the anti copy schemes work ?

ive seen articles regarding pc but not on ps2/ps1.

thnx guys

mods lock this thread if it offends u... >>



Who honestly wants to back up games LEGALLY?

If the software companies started offering replacement disc for $1 under the condition you send them in the damaged disc, will the demand for PSX copying scheme go down close to zero?
prolly not.

 

[crypticlogin]

<< i think you can write a disc that boots, and after that you dont need special CDs any more. >>



That's highly unlikely. As with the PSX discs, the PS2 discs also use a bit of proprietary space in the inner track so making your own bootable PS2 disc will probably be impossible with those special burners that Sony licenses, and if you did, might be a patent infringement. I think the linux kit uses a boot disc then uses the hard drive for the rest of the init so without that boot disc, you're still floating without a paddle.

Slashdot's discussion forums on bootable PS2 discs, especially the Linux kit

 

[Jejunum]

so u think that one of these days someones gonna hack the linux kit so u use the boot up disk then a burnt cd?

 

[crypticlogin]

<< so u think that one of these days someones gonna hack the linux kit so u use the boot up disk then a burnt cd? >>



If you mean a burnt CD like a game, I guess that's a possibility but the game will probably have chunks of the original (like some copied DC games) and wouldn't make the whole PS2 gaming experience worthwhile. If you mean a burnt CD as in an entire linux distribution, I guess someone might be able to but you have the hard drive so why bother?

My original meaning was that I didn't think a hacked linux boot disk, for whatever reason, would be possible since again, the boot info is stored proprietarily and proven impossible to create without the right machines.

 

[CTho9305]

<<

<< i think you can write a disc that boots, and after that you dont need special CDs any more. >>



That's highly unlikely. As with the PSX discs, the PS2 discs also use a bit of proprietary space in the inner track so making your own bootable PS2 disc will probably be impossible with those special burners that Sony licenses, and if you did, might be a patent infringement. I think the linux kit uses a boot disc then uses the hard drive for the rest of the init so without that boot disc, you're still floating without a paddle.

Slashdot's discussion forums on bootable PS2 discs, especially the Linux kit >>



sorry, let me clarify. You always need a proprietary disk to boot from. However, once you're booted, you could eject the disc and read from a standard CD-R if you want.

 

[Jejunum]

<< you could eject the disc and read from a standard CD-R if you want. >>



sweet linux kit is gonna rock then; think of all the neato stuff we will be able to do w/ ps2!

 

[Mday]

when i bought the total annihilation bundle, with both expansions, i read the booklet, and it was some $5 plus shipping to get the each of the CDs replaced
there were 4 CDs, and i paid $14 for it. so basically...

 

[Jejunum]

BUMPING THIS!

too see if anyone has any interesting discussion of what they think anandtech gurus will be doing w/ the linux kit; or what others will be doing...slashdot discussion is garbage!