Information pool: GameCube discs

[Killbat]

I don't know if anyone else cares, but I do at least. Please post here anything you know or have heard (even rumors, but please make that clear) about the format of the GameCube discs. Pool information and feed it to the curious, ya know?

I know very little at this point...
They are described by many as mini-DVDs, meaning I assume the same physical track form as DVDs, only smaller in diameter.
I tried to read some with my PC's DVD drive. The drive recognized them, but neither Windows XP nor any CDR software recognized the format. To me this indicates that the mini-DVD description is accurate, that is, a normal DVD drive can read them at the simplest level because the track is the correct size/spacing and spirals from the inside-out like normal discs (Xbox is reversed to protect the discs).
There are no obvious features in the data area of the disc (like the different density zones on Dreamcast discs that show up as rings), but on closer inspection, there is something at the center that is strange. It looks like a long, complex barcode around the innermost data area. It's not printed directly, it only shows up when looking at it from certain angles. It extends well within the readable area of the disc, so this must be part of a copy-protection scheme, not to prevent reading the disc on other systems, but for the GameCube to certify authentic game discs.
In summary

• physical tracks seem to be normal DVD format
• file system is not normal ISO (a la Playstation), no normal TOC is recognized by common PC software
• strange "barcode" is written in a ring over innermost data area, contains a massive string of data which may or may not vary from game to game (comparison is difficult, the code is very fine)

I'm interested in what other people have heard or found out!

 

[Mday]

if you look at a CD, you will notice the same kind of "writing" on it.

 

[Killbat]

No, not the markings in the spindle area, though the GCN discs have those, too. This code actually juts into the data area. It should be readable by the laser.

 

[Agent004]

Could the code be a region check, so that only the designated GCN/region can play the game?

 

[Killbat]

Ya think? I would expect that information to be contained in the actual game data somewhere, but that may be something.
I really think it's some kind of authentication so the console can tell if the disc is legal, but region checking could easily be a part of that.

How have previous disc-based systems region-checked?

 

[vash]

<< Ya think? I would expect that information to be contained in the actual game data somewhere, but that may be something. I really think it's some kind of authentication so the console can tell if the disc is legal, but region checking could easily be a part of that. How have previous disc-based systems region-checked? >>

Yes, all CD based systems in the past have been region coded (Sega CD, Saturn, PSX, PS2, Dreamcast and even GC). However, Nintendo usually make a physical difference for a region versus a software one for the games. With the SNES, all a a US user would have to do is break two tabs in the cartridge slot to accept an import game. With the GC, there is a simple switch you could make by soldering two leads in the GC. Most import shops are making a toggle switch or a plain switch to allow import games to run on US hardware, etc. Heck, even Nintendo spilled the beans when the GC hit the US shores. Sega and Sony are big on region coding, I am hopeful the Xbox won't be.

vash