Just exactly how does Swap Magic work?

I've heard that you "remove the CD without the system realizing it", but what does this mean?
Is it even possible to have the system keep reading something that isn't even there?
How do you change the discs, anyway?

I've not any knowledge of Swap Magic, but with the Swap Trick, you put a spring on the button that tells the system the tray is closed, meaning it will tell the system it's still reading a disc.

The system reads the disc in multiple stages. Checking for the country and if it's a real disc comes first. After that's done, put in another disc, and it will read it. Like, it used a real game as a fake I.D.

I have Swap Magic. What you do is put the Swap Magic DVD/CD into the PS2, it will boot up with some options.

Basically, depending on what PS2 you have, you can install a flip top or use a slide card tool. This will enable you to open up the DVD/CD tray without the PS2 knowing you have (there's a switch that is changed when you use the above methods). Then you insert the game you want to boot up (import or backup), and it will bypass the code that would initially reject it.

All you really need to know is that it will allow you to play imported and backed up games on your PS2 without the installation of a mod-chip. You shouldn't really worry about the ins and outs of how it works.

Note: Use Breaker Pro to play PS1 games.

Note: This would be better in the help forum.

An original PS2 disc is not burnt - it's pressed. That means that they can put stuff onto the disc that can't be put on by burning. Specifically, a burst cutting area, or BCA can be pressed. It can be fairly easily seen on the disc, as a slightly differently coloured ring around the innermost radius of the reflective data surface.

Essentially, the BCA is like a long barcode that goes around the disc, which the PS2 uses to identify the disc as authentic. Swap Magic discs are pressed with a real BCA, so the PS2 thinks it's an authentic disc when it loads. It stops loading after the BCA verification, so when you remove the disc to put in a burnt one the PS2 jumps straight to the game data payload of the disc and loads like normal. That's why you need to use a slide card or fliptop lid with the old PS2s and that little spring with the new ones to make sure the console doesn't realize you have opened the tray/lid.