there's a little ring around the outside of original games that are pressed on the discs that the laser goes to read before it boots the game, also there is country code protection which is in the boot sector
IIRC, TyRaNiD told me that the security check is requested from the SH-1 like any other CD function, and that any attempt to read CD data tracks will return garbage data until this is done. This suggests that the master SH-2 doesn't have much control over the check, meaning that something like a patched BIOS could not transparently avoid the protection (though it might be possible to stop the drive to make swapping easier)
The BIOS calls the check during the standard boot process, but if you have a cart such as an Action Replay 4M Plus, the boot process goes to the cart before the security check is done, and you could e.g. upload a program via commslink to verify this info or do other experimentation.
As Skank said, the territory indicator is in the boot area. It should be possible to make a multi-territory disc, but the current converter program doesn't do this. Also, the territory of the Saturn is controlled by jumpers on the system board; it's not hardcoded into the BIOS. Info on a territory mod can be found at http://www.gamesx.com/importmod/saturncon.htm
Well, whoever knows that much about the mechanism probably isn't talking. However, there has to at least be some kind of pattern that the CD reader can pick up. Whether or not it's meaningful in any other way is anyone's guess. By the way, the idea that the protection depends on the ring isn't merely conjecture (as were some of the theories about PSX protection); if you know how to do a double swap and observe the laser's movement, it's clear that the laser is reading that region.
It looks for the ring, wich isn't part of the data track. If the ring were part of the data track (in some way), copying saturn cds would be impossible without special modified equipment wich none of us is able to pay.
In theory, its possible to read and copy the "ring". But you would need to modify your burner (I'm not sure), with the risk to make it unusable in the first try.
On the back of every jewel case in tiny print there are usually 4 or 5 US patent numbers, most of them describing systems for copy protection. Do a numeric search for the number 5,371,792. This number is by far the most telling of the ones listed. It describes where the rings are, how the processors are sequenced, etc. It doesn't describe how the copy protection data is written on the CD-ROM or any other "trade secret," but the info is useful enough in understanding better what happens when the Saturn encounters a CD. If you're really bored, look up the other numbers too. It's kinda amazing the amount of work programmers went/go through in the name protecting intellectual property.
I can't view the images, but I'm pretty sure the patent number you refer to describes a different type of protection, one that is designed to hinder unlicensed development. A scheme along these lines exists on Mega/Sega CD and Dreamcast, and a simpler version is even found in later models of Genesis/Megadrive. Basically, the game media must contain a particular program that is compared to one in the BIOS. If they are the same, the code is executed. This is the code that displays the "Produced by or under license from Sega Enterprises" screen, and also the logo I believe. The point of all this is that the code is (presumably) protected by copyright law, and thus in order to produce a disc that will run on the Saturn, a license must be obtained or the publisher will risk being sued by Sega for copyright infringement. Nintendo uses a similar scheme for Game Boy.
i tried something today, I watched carefully what happened at the time when you're supposed to switch the disk(when the security code is searched) and when i tried with a small backup (about 5 mb) and the laser beam didnt try to scan for the security code at the end of the cd, it searched around the end of the data track...
if u guys have the opportunity plz try this with different backups and tell me your results
Track 01: Total bytes read/written: 909312/909312 (444 sectors).
My Saturn still moves the laser all the way out, assuming that I swap properly. If not, it just spins the disc really fast and fails to read it, but it does that with CD-Rs anyway. This may mean that there's some kind of dummy track on pressed Saturn CDs for the laser to follow that's not in the TOC, but I doubt this somewhat due to the speed at which the laser moves.
Track 01: Total bytes read/written: 700909568/700909568 (342241 sectors).
(80 minute disc, btw )
This is the same ISO as before with 700,000,256 bytes of zero data added on. The laser seems to act a bit more normally with this, checking for a bit (I can tell from the sound that the movement isn't quite the same, so it's not seeing something that it wants to) then dumping to the BIOS screen, which gives the error message "Disc unsuitable for this system." (note that this message is different than "Game disc unsuitable for this system.", which means that the territory did not match).
Anyways, I've been looking around e several places for info, and I came up with a tool that is able to read ANY sector from a cd, even beyond the leadout, the problem is that most cdrom drives don't allow this.. I've been told that some plextor cdrom drives are able to read past the leadout, I don't know this is true, but if anybody has one of these cdroms...
The tool can be found here on the downloads section...