Abstract: A method of performing set operations on ordered sets includes the steps of receiving a first ordered set and a second ordered set. A set operation request between the first ordered set and the second ordered set is received. A modified binary search is performed between the first ordered set and the second ordered set to find an intersection set.

Abstract: A computer having both volatile and nonvolatile memory, and which is operative in response to a system program and an application program, is protected against an interruption of a primary power source by a momentary introduction of power from a backup source, and by a freezing of data and program instructions in effect at the time of the power interruption. A backup region is designated within the nonvolatile storage medium for receipt of data and instructions present in the nonvolatile memory upon the occurrence of a power interruption. Circuitry is provided for sensing the interruption, the circuitry including the implementation of a computer program which directs cessation of further operation of the application program followed by a transfer of data and instructions from the volatile memory to the nonvolatile memory. This transfer is done under backup power. Thereupon, the backup power is discontinued and the computer is shut down.

Abstract: Digital data storage methods and apparatus in which the addresses or records stored in a storage memory are themselves stored in corresponding entries in a catalog memory, each entry in the catalog memory also includes a confirmer derived from a key extracted from the corresponding record in the storage memory, and a limited number of the entries in the catalog memory are enchained with chainhead entries.