When talking about Digital Video Recorders, three specific brands come to mind. The first producer of these products is TiVo. From 1997 TiVo has been a pioneer in digital video recording services. The next producer is from the Ultimate TV division of Microsoft. With the backing of Microsoft, the Ultimate TV unit has been able to compete with the other producers and offer similar services. The final brand when mentioning DVRs is ReplayTV. ReplayTV comes from the SONICblue Corporation, who also produces products under the Diamond Multimedia name and the Rio handheld MP3 players. .
The best way to describe a digital video recorder is to call it a VCR that doesn't use tapes and provides information that you find in a TV Guide. Although several companies produce different styles of digital video recorders, they all contain some of the same features. The DVR is a small computer with only one task, to digitally record video. Each recorder contains a hard drive ranging in size from 30 GB up to 120 GB, depending on the length of video the recorder holds. Using current video compression technology the recorder can hold roughly 1 hour per GB, using the lowest quality grade. In addition to recording shows like a VCR would be able to do, the DVRs can pause live TV by digitally recording television as it is watched. For example, you would like to get a drink in the middle of a football game. No problems with a DVR, just pause the TV then resume play when you return. You can then catch up with live TV during the commercial breaks. With all these features the viewer can rewind, pause, and fast-forward (up to "live" state) television as they watch.
One of the most noticeable features of each recorder is its software. The TiVo software allows a viewer-selected program to be set on "Season Pass", which means that program will be recorded by TiVo for every episode, even if during the season the date and time slot changes.