GCN Why can't you just copy a GC Disk 1:1 ? How does the GC prevent that?

[Der_Blockbuster]

Hello, I've heard that the GC Disk are burned backwards, but I don't think that this makes Copying the games impossible.
How does the GC know that?

 

[Cyan]

That's a myth, the disc is not spinning backward, nor is written in reversed order (side to center).

a very good website (unfortunately not online anymore) explained how the data was written on the disc.
hopefully, you can still read it thanks to web archive
http://web.archive.org/web/20080619172414/http://www.ingenieria-inversa.cl:80/?p=9

having a non standard layout, only one computer DVD drive model could read it without rejecting the disc.


the author (xt5) released a program which applied that structure information to unscramble (re-position/shift) the data in order to allow standard disc reader/writer to understand the data. if you have a burned disc, it has already been "shifted".
real 1:1 disc image are not really 1:1 or they couldn't be understood by the burner program if they were burned right away. 1:1 dump are raw (the first Wii disc were raw and couldn't be burned as ISO).
"1:1" as people know it are in fact restructured to be standard ISO9660.
I'm not sure about GC disc format, but the site is explaining GOD/WOD format as if it was the same.

edit:
the web archive is not properly formating the text, for users who are really interested about the layout structure, here is the correct one :

Spoiler: disc raw layout

DVD-ROM:



   4bytes   2bytes      6bytes                 2048bytes                       4bytes

 -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

|     ID    | IED |     CPR_MAI     |             User Data Frame             |    EDC    |

 -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

          ^                         |         2048bytes cipher stream         |

          ^                          -  -  -  -  -  -  -  -  -  -  -  -  -  -

       scrambling

       seed index



Gamecube/WII Optical Disc:



   4bytes   2bytes                  2048bytes                     6bytes         4bytes

 -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

|     ID    | IED |             User Data Frame             |     unknown     |    EDC    |

 -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

                                    |         2048bytes cipher stream         |

                                     -  -  -  -  -  -  -  -  -  -  -  -  -  -

that website was also later responsible for TruchaSigner (program to decrypt/extract/inject/resign Wii discs, back in 2008) and another program did the same thing and was more known and still used nowadays (Wiiscrubber).

 

[Der_Blockbuster]

That's a myth, the disc is not spinning backward, nor is written in reversed order (side to center).

a very good website (unfortunately not online anymore) explained how the data was written on the disc.
hopefully, you can still read it thanks to web archive
http://web.archive.org/web/20080619172414/http://www.ingenieria-inversa.cl:80/?p=9

having a non standard layout, only one computer DVD drive model could read it without rejecting the disc.


the author (xt5) released a program which applied that structure information to unscramble (re-position/shift) the data in order to allow standard disc reader/writer to understand the data. if you have a burned disc, it has already been "shifted".
real 1:1 disc are not really 1:1 if they can be burned right away. 1:1 dump are raw (the first Wii disc were raw and couldn't be burned as ISO).
I'm not sure about GC disc format, but the site is explaining GOD/WOD format as if it was the same.

edit:
the web archive is not properly formating the text, for users who are really interesting about the technical layout, here is the correct one :

Spoiler: disc raw layout

DVD-ROM:



   4bytes   2bytes      6bytes                 2048bytes             4bytes

 -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

|     ID    | IED |     CPR_MAI     |             User Data Frame             |    EDC    |

 -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

          ^                         |         2048bytes cipher stream         |

          ^                          -  -  -  -  -  -  -  -  -  -  -  -  -  -

       scrambling

       seed index



Gamecube/WII Optical Disc:



   4bytes   2bytes                  2048bytes                     6bytes         4bytes

 -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

|     ID    | IED |             User Data Frame             |     unknown     |    EDC    |

 -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -

                                    |         2048bytes cipher stream         |

                                     -  -  -  -  -  -  -  -  -  -  -  -  -  -

that website was also later responsible for TruchaSigner (program to decrypt/extract/inject/resign Wii discs, back in 2008) and another

Alright thank you, it seems like theres much more behind it then I thought.
Allthough a DVD Drive with the right firmware could be an Idea, but thats just me guessing. If it was that easy, there would be tools ect. already.