The core functionality of a Digital Video Recorder (DVR) is to record and playback broadcast multimedia content such as video content (and any audio content corresponding thereto, but collectively referred to hereinafter as “video content” for the sake of brevity). Many DVRs allow time-shift functionality. Time-shift functionality is essentially a rolling buffer of live broadcast content. This allows trick mode operations such as pause, rewind, and fast forward to be used on live broadcast content. A typical time-shift implementation will maintain a buffer of the last 30 minutes of live broadcast content, allowing the user to navigate this buffer with trick modes.
Since the storage of video content requires significant storage space, the video data used for time-shift functionality is usually stored on a hard disk in most implementations. This presents problems because as new data is added to a time-shift recording, old data must be truncated from the end. While most file systems allow efficient insertion of new data at the end of a file, most file systems do not provide an efficient mechanism for truncating data from the beginning of a file. Some DVRs solve this problem by using a specially designed file system that provides for insertion at the end of a file as well as truncation from the beginning of a file. However, the use of a specially designed file system is not with deficiencies including, but not limited to, the integration of such specially designed file systems with the standard file systems that are also used in DVRs.