Abstract: A file system stores data and meta-data in a like fashion. The lowest level of stored file data on disk is a stream, which constitutes a logically contiguous group of bytes. Related streams, such as found in a file, a directory or a subdirectory, are stored in a variable-sized onode data structure. Variable-sized onode data structures are stored in an array of fixed-sized buckets of disk space. Related onode data structures are stored within catalog data structures. The catalog data structures are stored within the array of fixed-sized buckets of disk space. The array of buckets of fixed-sized buckets of disk space is, in turn, stored as a stream.

Abstract: File data is stored in a number of different representations on disk. File data is stored in streams which may assume any of several different representations. Each stream has an associated stream descriptor which describes how the stream is stored on the disk. The representations include storage of a stream in a single extent, storage of a stream in multiple extents and storage of a stream in an associated stream descriptor.

Abstract: A modified buddy system is adopted for managing disk space in a disk storage. The modified buddy system uses a minimal amount of memory space and provides very quick access to extents within the disk space. The modified buddy system utilizes a tree structure of nodes, wherein each node represents an extent of disk space. A bitmap is provided for holding state bits for each of the nodes in the tree structure. The bitmap is organized to preserve locality of reference.

Abstract: A file system provides a hierarchical approach to storage of file data. Logically contiguous bytes of file data are stored in stream data structures, and streams which hold related file data are stored in a variable sized onode data structures on disk. The variable-sized onode data structures are stored in fixed sized buckets, and the buckets are organized into a variable sized array. Thus, the file system provides a combination of variable-sized storage with fixed-sized storage to provide a very efficient approach to storing file data. In addition, indexes may be provided within the structures to allow quick access to onodes and streams.

Abstract: A portion of a first storage stores identifying information of files to be processed by a computer. The files are stored in a second storage, with each file having associated identifying information which identifies the file, and each file including an update sequence value which indicates an order in which the file is to be processed by the computer. A threshold value is provided which is set equal to a largest update sequence value retrieved from the file that have been processed by the computer. In response to a loss of the file identifiers stored in the portion of the first storage, the file identifier for each file whose update sequence value is beyond the threshold value is stored in the portion of the first storage.

Abstract: A modified buddy system is adopted for managing disk space in a disk storage. The modified buddy system uses a minimal amount of memory space and provides very quick access to extents within the disk space. The modified buddy system utilizes a tree structure of nodes, wherein each node represents an extent of disk space. A bitmap is provided for holding state bits for each of the nodes in the tree structure. The bitmap is organized to preserve locality of reference.