Informational: An interesting DRM invention in the PS1, was the "bounce" that all PS1 discs had at the beginning of the read.

The lazer would follow the read path of the disc, and watch for a specific wobble. If the wobble was there, the DRM passed, and the disc would load.

You would often hear people touting that you could place a ps1 disc in the tray to get it started (with the "lid-closed" pin held down with tape), then swap out the disc to a burned one to play it. This would work because of that drm system :D