How TIVO Can Stop and Start Live TV

For many people, their first encounter with a TIVO system is like watching real magic happen. Live television stops and starts on cue. This ability means no more missing key plays or funny lines during programs. You can actually stop the action and go to the bathroom. When you return, you will have missed nothing. This wonderful device can change how you watch television forever. However, it might very well cause you to miss sleep worrying about how it works.

A DVR is a relatively simple device. It does not require a PhD or other sophisticated education to really have a grasp of how it does its work. Inside the DVR is a hard drive just like the one sitting inside your home computer. The storage capacity can vary from machine to machine with most being between 40 and 150 hours of video storage possible. This hard drive is the key to the device's magic.

Inside the hard drive is one or more disc's. These are accessed by read and write heads in the same way that the heads on your old tape recorder accessed the magnetic information on the tape. Instead of the tape sliding over the heads, the heads fly just thousandths of an inch above the surface of the top and bottom of the discs as the the discs spin. They are able to write to the media and read it back.

The first step to making this work is to insert multiple heads inside the hard drive. A digital video recorder has three or more heads available to be used. Three is the usual number. They are divided up as two write heads and one read head. Since no television that is readily available for the general public can broadcast two channels simultaneously, only one read head is necessary. In order to be able to record two programs at the same time, two write heads are needed. By having this, you can watch a pre-recorded program from the disc with the read head while recording up to two more programs on the disc with the write heads.