The discs - roughly seven or eight per system - can hold much more information than the old hard drives did.

This disc holds some very important, top secret information.

The disc holds an hour per side at its low-quality setting, but that is too low to bother with.

This disc could hold an hour of analog video along with digital audio on both sides.

Each disc can hold slightly over 90 minutes of sound, so longer films will require a second disc.

Each disc holds one region's worth of maps and information.

Depending on the camcorder's settings, a disc can hold 30 minutes to two hours of video.

The new discs will hold four to five times the digital video and audio data of those currently on the market.

Yet this disc holds much more than local or specialist interest.

A 10-inch 78-rpm disc could hold about 3 minutes of music per side.