|Computer file system providing looped file structure for post-occurrence data collection of asynchronous events
|Avid Technology, Inc.
|March 7, 2000/ April 3, 1997
|Relates to storing video on a hard disk in much the way that the Minidisc "Time machine" recording function works. Interestingly, this patent references Minidisc.org(!), refering to information there about the Sony MDS-503.
|An operating system has a file system which supports writing data to a file in a logical loop of clusters of storage locations. Writing can be performed in looped or unlooped modes, and a transition between looping and non-looped recording may be supported. Recording prior to occurrence of an asynchronous event is performed in a looped mode. After occurrence of the asynchronous event, the data collected in the looped portion is seamlessly merged with subsequently collected data by manipulation of pointers to the clusters by the operating system. By providing such a general structure for use in a file system of a computer, a substantially larger amount of memory is available for looped recording. In fact, several minutes of full motion broadcast quality video may be captured. In addition, by using the file system to handle the storage of data, an application does not need to arrange recorded information on a physical recording medium. Such a file system may be used in any application which collects data for the purpose of capturing the occurrence of an asynchronous event. Such applications include, but are not limited to, motion video recording, surveillance, test data collection, and other types of systems that need to record events that precede some arbitrary "trigger" condition and which may require a large amount of storage.