woah, woah, woah... that link isn't so right...

The system disc is a developers tool used to load CD-R's of games in development.

It works like a boot disc. You put the system disc in, wait a few seconds for it to do it's thing, then put the CD-R in and press start. The saturn loads up the CD-R.

There are two different color system discs, one for 1st party development, one for 3rd party development. They're distinguished by their color, red and black (there's also a blue one, but i don't know what that one does). I'm colorblind, so i can never remember which is 1st party and which is third.

I have some more info on system discs (and a whole lot more development tools) on my website. The link is in the sig... I've seen the discs sell for $2 and i've seen them sell for $100, so it all depends on who you're selling to.

BTW, the number written in marker on the disc? That's the serial number. Sega can use that number to trace back the owner of the disc if it were ever sold on the black market (do they care any more? i don't know).