eli5: If game console CDs just tell the game console “yeah they own this game” what was stopping people from just copying the data to other CDs and giving it to people?


(besides legally)

In: 6

5 Answers

Anonymous 0 Comments

Burnable CDs are marked as such on the disc, indicating their types, safe write speeds, and other data. Console discs are usually in some way off-spec that the console can detect to validate the disc is legit. So it can tell copied games and legit games, and would refuse the wrong type.

Hacks existed, from swapping discs with the lid open at the right moment after the disc was accepted, to firmware hacking the CD drive itself to send bogus data to the game console, but as is, game consoles can tell real CDs.

Anonymous 0 Comments

Disk Formats. On the disk is just ones and zeros, and we depend on standards to determine how to read that data in a standard disk drive. The game company doesn’t tell you how the disks are formatted, so it might not be readable unless you use the required software

Software/encryption. The data get disguised in such a way that unless you know the associated key code, the game will refuse to play. You might remember older games had activation codes with them for this purpose. Nowadays, the game might have an embedded code that gets read behind the scenes (like when you’re required to connect it to your online account). Same general idea though.

Most of this technology falls under the umbrella of Digital Rights Management (DRM), which is constantly growing more and more sophisticated

Anonymous 0 Comments

Firstly, that’s not all CDs do (usually).

Older systems read the game straight from the cd. If you didn’t have the cd the computer couldn’t read anything to play.

More modern systems often download the game from the cd to the console (or sometimes from the internet to the console), and it uses the cd as a kind of permission. So you still need the cd in the first place. After that, you’re right it could technically be replaced, but there is all sorts of piracy protection.

For a start modern consoles don’t use cd, they use discs with a different storage technology that both allows for much more data (GBs compared to a cd with 700mb) and is more difficult (expensive) to replicate. Then on top of just the expense of replicating there’s almost certainly various encryption systems that the console needs to authorise making it more difficult.

If you can bypass those encryption systems then by all means you can write your own discs. That’s generally known as piracy and is frowned upon with varying intensities depending on who you are.

Anonymous 0 Comments

1. They can usually detect you are using a different type of disc.

2. Each disc may use a unique code and require the system to use a network connection to validate periodically.

Anonymous 0 Comments

Each console has a slightly different way of constructing a disc that is impossible to be replicated with fidelity with consumer equipment, sometimes even professional replication towers.

Taking Xbox DVDs for example.

The disc have decoy information in the inner rim lead-in section and first few megabytes of the data section, pretending to be a DVD-9 movie of a few megabytes. The real metadata for the disc is at the outer rim.

There are gaps of absolutely nothing between the DVD movie partition and real game data partition.

The above two prevents any consumer DVD drives, which respects limitation parameters in the lead-in section, from moving the laser past the gap, therefore not possible to read any actual game data.

The lead-in information of a burnable disc already contained something else, therefore it is not possible to pose a burnable disc as a genuine game disc without hacking the drive.

Then there are various security sectors created in a way to be non-compliant according to official DVD standards, like altered pit length modulation, altered error correction scheme, wrong physical sector numbers, specifically crafted tracks with wobbles, overlapping destroyed tracks by burning the area twice.

These sectors will either be unreadable or be read as something else according to error correction schemes of a standard DVD, or impossible to be recreated even with industrial grade mastering equipment because physical tolerances always create a unique result each time a disc is mastered.

Then the angular distance of certain data sectors will be measured and compared, because consumer burners and even professional mastering equipment will not be able to accurately reproduce this feature either. Consumer burnable discs are already pre-indexed and will have a different angle, professionally mastered discs will always have a slightly different angle due to speed variances when mastering.

Create, measure and record those parameters to create a unique disc signature, which can easily be measured by console drives, but impossible to fake, therefore the discs can never be faked without hacking the drive to lie about the measurement results.