Extending cluster allocations in an extensible file system
An extensible file system format for portable storage media is provided. The extensible file system format includes the specification of primary and secondary directory entry types that may be custom defined. The primary and secondary directory entry types can be further classified as critical and benign directory entries. The directory entry types can define whether a cluster chain corresponding to a file can be contiguously allocated.
1. A computer-readable storage medium on which computer-readable components for storing data are stored, the computer-readable components comprising:
a file allocation table component for defining a file allocation table associated with a file system; and
a primary directory entry for specifying data in a directory of the file system, wherein the primary directory entry includes a flag corresponding to an indication of whether the data corresponding to the primary directory entry is stored in a contiguous cluster chain.
2. The computer-readable medium of claim 1 , wherein when the flag indicates the data is stored in a contiguous cluster chain, the file allocation table is not traversed to identify the data by the file system.
3. The computer-readable medium of claim 2 , wherein the primary directory entry includes starting cluster information and a cluster chain size for the contiguous cluster chain.
4. The computer-readable medium of claim 1 , wherein when the flag indicates the data is not stored in a contiguous cluster chain, the file allocation table is traversed to identify the data by the file system.
5. The computer-readable medium of claim 1 , wherein the computer-readable components further comprise:
a secondary directory entry corresponding to the primary directory entry and defining meta data associated with the primary directory entry.
6. The computer-readable medium of claim 1 , the computer-readable components further comprising:
a boot parameters component for specifying boot parameters for the file system.
7. A computer-readable storage medium on which computer-readable components for storing data are stored, the computer-readable components comprising:
a file allocation table component for defining a file allocation table associated with a file system; and
means for specifying contiguous clusters of data in a directory of the file system.
8. The computer-readable medium as recited in claim 7 wherein the means for specifying contiguous clusters of data in a directory of the file system includes a contiguous allocation flag indicative of a contiguous allocation of data clusters.
9. The computer-readable medium recited in claim 7 wherein the means for specifying contiguous clusters of data in a directory of the file system includes a primary directory entry for specifying data in a directory of the file system, wherein the primary directory entry includes a flag indicating whether the data corresponding to the primary directory entry is stored in a contiguous cluster chain.
10. The computer-readable medium recited in claim 9 wherein when the flag indicates the data is stored in a contiguous cluster chain, the file allocation table is not traversed to identify the data by the file system.
11. The computer-readable medium recited in claim 9 wherein when the flag indicates the data is not stored in a contiguous cluster chain, the file allocation table is traversed to identify the data by the file system.
12. The computer-readable medium recited in claim 7 wherein the means for specifying contiguous clusters of data in a directory of the file system includes a secondary directory entry for specifying data in a directory of the file system, wherein the secondary directory entry includes a flag indicating when the data corresponding to the secondary directory entry is stored in a contiguous cluster chain.
13. The computer-readable medium of claim 7 , the computer-readable components further comprising:
a boot parameters component for specifying boot parameters for the file system.
14. A computing device comprising a computer readable storage medium including computer readable components, the computer readable components comprising:
a file allocation table component for defining a file allocation table associated with a file system; and
a primary directory entry for specifying data of the file system, wherein the primary directory entry includes an indicator indicating whether the data corresponding to the primary directory entry is stored in a contiguous cluster chain.
15. The computing device of claim 14 wherein when the indicator indicates the data is stored in a contiguous cluster chain, the file allocation table is not traversed to identify the data by the file system.
16. The computing device of claim 15 wherein the primary directory entry component includes starting cluster information and a cluster chain size for the contiguous cluster chain.
17. The computing device of claim 16 wherein the computer-readable components further comprise:
another primary directory entry corresponding to an allocation bitmap defining cluster availability within a storage media, the file system using the starting cluster information and the cluster chain size to identify the data via the allocation bitmap.
18. The computing device of claim 14 wherein when the indicator indicates the data is not stored in a contiguous cluster chain, the file allocation table is traversed to identify the data by the file system.
19. The computing device of claim 14 , the computer readable components further comprising:
a boot parameters component for specifying boot parameters for the file system.
20. A computer-readable storage medium on which computer-readable components for storing data are stored, the computer-readable components comprising:
a file allocation table component for defining a file allocation table associated with a file system; and
a primary directory entry for specifying data in a directory of the file system, wherein the primary directory entry includes:
a flag that indicates whether the data corresponding to the primary directory entry is stored in a contiguous cluster chain; and
other information that specifies a starting cluster of a first contiguous cluster chain and information concerning a size of the first contiguous cluster chain when the flag indicates the data corresponding to the primary directory entry is stored contiguously, the other information enabling identification of each cluster in the first contiguous cluster chain without having to traverse the file allocation table.
21. The computer-readable storage medium of claim 20 , wherein when the flag indicates the data is not stored in a contiguous cluster chain, the file allocation table is traversed to identify the data by the file system.
22. The computer-readable storage medium of claim 20 , wherein the computer-readable components further comprise:
a secondary directory entry corresponding to the primary directory entry and defining meta data associated with the primary directory entry.
23. The computer-readable storage medium of claim 22 , wherein the secondary directory entry includes:
a flag that indicates whether the data corresponding to the secondary directory entry is stored in a contiguous cluster chain; and
other information that specifies a starting cluster of a second contiguous cluster chain and information concerning a size of the second contiguous cluster chain when the flag indicates the data corresponding to the secondary directory entry is stored contiguously, the other information enabling identification of each cluster in the second contiguous cluster chain without having to traverse the file allocation table.
24. The computer-readable storage medium of claim 20 , the computer-readable components further comprising:
a boot parameters component for specifying boot parameters for the file system.