During the boot process the Saturn would check the drive for an authentic disc. Once the check passed, the drive paused and prepared to boot the game.
At this point of pause you could swap the authentic disc to a completely different pirated game (one burned onto a normal CD-R that would fail the first boot check).. Timing the swap correctly, the Saturn would play the pirated game.
The Pseudo Saturn Action reply hack to circumvent disc checks was only within recent years released.
(Also, someone had downvoted you, which I disagree with completely. If I'm wrong, I'm wrong. So, here's an upvote to balance it out.)
I also jumped on the XBMC and Xecutor modchip for the original Xbox when that came out. Another mind blowing time in computer gaming.
Consumer CD Burners didn’t have firmware (or maybe even the physical capability) to reproduce these “errors”.
Imagine a vinyl record where the start of the track has a groove that isn’t perfectly tracing the perimeter, but is actually a low amplitude sine wave of a certain frequency, waving in to the center and out to the perimeter. Any record player could trace the groove correctly, despite the fact that there is a low amplitude sine wave, and you’d hear the audio correctly (error correction). But a special record player could even detect the sine wave and reject records that don’t have it. I’m hand-waving away the fact that you’d get a little bit of wow and flutter from the sine wave, but you get the idea.
Afaik Wobble is pre molded in polycarbonate layer and cant be altered by CD Writer no matter the firmware.
I don't know about CDs / BluRays but similar to what user jaywalk answered: back in the floppy disks days some copy-protection relied on physical differences created on purpose on the original game. It could be something as "simple" as damaging a track on purpose, by punching a hole in it. Then the game would try to read the data, any data, from that track. And the read command had to fail. A dumb block level copy wouldn't work: it could of course not physically punch a hole in a floppy disk.
So pirate groups would crack the game and ship a version of the game without the copy protection and these could be copied at will.
for x = 1 to 10:
total += (read $DAMAGED_BLOCK) mod 2
assert total > 2 and total < 8
Plain English explanation of the above code would be read a sector multiple times, make sure it is never always just even or just odd, but instead varies.
Usually perfection in digital media is what you strive for, but strategically introducing imperfections has a long history in authenticating “genuine” products.
One of the original methods used as copy protection used a special industrial writer write a invalid block, data was ok but the error correction would say it's something different, and check because the consumer hardware wouldn't read or write these blocks.
Do you just have a Blu-Ray optical burner? Burned discs are typically simple to distinguish from pressed discs, so you can't make an exact copy.
Some early CD systems were made before CD-Rs were common (or maybe even contemplated) and didn't have mechanisms to check media type, but modern consoles know about these things.