|VC, DV, NV Recorders|
VCR is Video Cassette Recorder
VCR is the oldest type of recorder of the 3 whereas DVR is more recent and NVR is the latest as of 2008. VCR records video images on a tape cassette and the tape runs from one end to the other in a fixed sequence. We will have to go through the beginning to the end to search for a video frame taken at a specific instant.
DVR uses a computer hard disk for recording. Hard disk allows random access (or against serial access) and fast retrieval of specified images. Hard disk is also cheap as it is a standard PC product.
NVR refers to an open standard computer as the recording device instead of a proprietary or closed design box as for DVR. All open standard computers have network interface that is IP compliant. Therefore NVR is normally refer to as part of a full (end to end) IP based surveillance system.