Digital video recorders' or 'DVRs' for short are stand alone devices which feature a hard disk for storing recorded digital data. Some manufacturers have combined DVRs with DVD recorders. This means that users have two options, they can record straight onto DVD, or to a hard disk.

Furthermore, they can use the stored data on the hard disk to record onto a DVD at a later date. This offers increased convenience in comparison to directly recorded DVD recorders.

A combined DVR/DVD Recorder avoids the possibility of recording something you don't like onto a one time recordable DVD, and wasting the cost of the DVD into the bargain.

DVRs are sometimes referred to as plus boxes in the UK, this is due to the astounding success of BSKYB's sky+ box.

However, this is just one example of a DVR box, it was not the original, and companies such as Virgin Media have released a V+ box to compete with Sky. The Sky+ box has been commended for its simplicity.

DVRs are easier to use videoplus+, which required a paper TV guide to locate the relevant recording code. Sky and Virgin provide a free daily digital menu of programme listings. All that's required is for a user to select the programme and press the record button.

A drawback to DVRs is the time restraints in the digital menu. It's not as easy to record programmes a day or a week in advance. Advertising revenue may also be impacted, as users can begin their viewing schedule later, and forward through the advertisements.

However, this has not stopped cable and satellite companies following BSKYB's lead and incorporating a DVR feature into their set top box.

The United States regulatory body for broadcasting has recently stipulated that cable companies must provide third party manufacturers the opportunity to incorporate DVR technology into existing receivers.