Disk driver cluster management of time shift buffer with file allocation table structure
View Patent ↗A file allocation system for a hard disk drive includes a memory with driver logic and a processor configured with the driver logic to receive a request to allocate hard disk space of a defined size for a buffer file. In some embodiments, the processor is configured with the driver logic to allocate clusters for the buffer file from a plurality of clusters on the hard disk, wherein the clusters for the buffer file store media content instances. In some embodiments, the processor is configured with the driver logic to designate a portion of the clusters of the buffer file for at least one non-buffer file such that the non-buffer file is permitted to share the portion of the clusters of the buffer file with the buffer file.
1. A computer readable medium having a file allocation table encoded thereon, said table comprising:
a first data structure comprising file list entries for files, wherein the file list entries include clusters allocated for each of the files; and
a second data structure comprising cluster list entries for the clusters, wherein the cluster list entries identify the clusters and a quantity of the files that simultaneously share each one of the clusters, wherein a quantity value is at least two, and wherein a quantity value greater than one indicates that the cluster not be deleted.
2. The computer readable medium of claim 1 , wherein the file list entries further include a filename for each of the files and a starting and ending sector of each of the files.
3. The computer readable medium of claim 1 , wherein the quantity of the files that share each one of the clusters is tracked in a file sharing counter.
4. The computer readable medium of claim 3 , wherein the file sharing counter can have values of zero to signify that a corresponding cluster is available to be written to, values of one to signify that a corresponding cluster is used for a buffer file, and values greater than one to signify that corresponding clusters are to be used for permanent recordings.
5. The computer readable medium of claim 1 , wherein the cluster list is updated such that a buffer file of clusters is limited to a substantially constant buffer file size, such that when the buffer file approaches a full status, the cluster storing the oldest media content is first deallocated from the buffer file a new cluster is correspondingly allocated to the buffer file.
6. The computer readable medium of claim 1 , wherein said files are buffer files or non-buffer files.
7. The computer readable medium of claim 6 , wherein the non-buffer file is a permanently recorded file that can be deleted.
8. The computer readable medium of claim 1 , wherein file allocation table data can be updated at the request of an application or based on pre-programmed timer events initiated by an application.
9. The computer readable medium of claim 6 , wherein a normal play time value is provided to track a current write and read location when writing media content instances to the clusters of the buffer or non-buffer file.
10. The computer readable medium of claim 6 , wherein replacement clusters replace the portion of clusters that are shared by the buffer file and the non-buffer file in order to maintain a defined size of disk space for the buffer file as substantially constant.