Picture-in-picture the screen. Televisions at the time were still analog format, and earlier versions of the PiP implemented in analog were too costly. New digital technology allowed the second video signal to be digitized and saved in a digital memory chip then replayed in a mini version. While the new technology was not good enough for color or full-screen viewing, it did provide a low-cost PiP feature. The Blu-ray Disc and HD DVD specifications included picture in picture, allowing viewers to see, say, the director's comment on a film they are watching. All of the Blu-ray Disc titles in 2006 and
Optical disc drive inexpensive, are suitable where read/write capability is required. Disc recording is restricted to storing files playable on consumer appliances (films, music, etc.), relatively small volumes of data (e.g. a standard DVD holds 4.7 gigabytes) for local use, and data for distribution, but only on a small scale; mass-producing large numbers of identical discs is cheaper and faster than individual recording. Optical discs are used to back up relatively small volumes of data, but backing up of entire hard drives, which typically contain many hundreds of gigabytes or even multiple terabytes, is less practical. Large backups are often instead made on