Never mind DMCA, what about copyright law (Score 1)

If Microsoft were smart about this, there's any easy solution to make sure that people don't produce games without buying a licence.

All you need to do is check that there is a unique key at the start of the disc, along the lines of "This game uses code licensed from Micro$oft, (c) 2001 Micro$oft and can only be used by paying large $ums of money". If the disc doesn't have exactly that text then the OS can easily refuse to run it.

No need for digital signing, encryption, etc... If someone produces a disc containing that text, the Microsoft can argue that as it contains a copyright message assigning copyright of some portion of it to them, that they have right to a licence fee for the use of that. It doesn't matter that it's just a piece of text, it would still be covered under copyright.

The only way I see around this is someone producing a patch for the OS to remove such a check.

Ralf.