Abstract: A method and apparatus for accessing data in a data base that provides for a minimum of unused storage while preserving easy expandability. A group of accessing keys are used to identify the attributes data that is being sought in a data base. In accordance with the invention, subkeys are extracted from members of the group of data accessing keys and these subkeys are advantageously rearranged to form derived accessing keys. Subkeys are densely populataed if most values of a subkey are used in most systems. One of the derived accessing keys, derived from densely populated subkeys is used for accessing the tables of data attributes that are therefore advantageously densely populated. Another derived accessing key, derived from sparsely populated subkeys, is used for accessing a sparsely populated head table. Derived keys of intermediate population density are used for accessing tables intermediate between the head tables and the tables of data attributes.

Abstract: A method and apparatus for transmitting messages from one processor to a plurality of other processors in a distributed processing system having no hardware message broadcast facilities. The transmitting processor includes a broadcast program process for controlling the transmission of any messages destined for a plurality of other processors. Different client processes in the transmitting processor request the broadcast process to transmit a broadcast message. The single broadcast process controls the number of individual messages which are sent out sequentially to each of the receiving processors in such a way as to ensure that the broadcast messages do not interfere with other message traffic that frequently has tighter delivery time requirements. The broadcast process transmits the broadcast messages to each of the plurality of recipient processors without waiting for acknowledgment response messages from any of these processors.

Abstract: A distributed control switching system where the system control units cooperatively perform the terminating port determination function. Multi-port hunt groups having members that span a number of switching modules each having an associated control entity, are controlled in an efficient manner by assigning, for each multi-port hunt group, one of the switching modules as the group controller for that multi-port group. All calls to a given group necessarily require a control communication with the group controller which maintains the dynamic busy/idle data for the group and performs the hunting function to assign idle group members to calls.

Abstract: A distributed control switching system where the system control units cooperatively perform the terminating port determination function. In particular, the directory number translation function is done in a manner allowing flexibility in assigning directory numbers to switching system ports but minimizing the magnitude of the storage facilities required in each control unit. Each control unit stores the complete directory number translation for certain directory numbers but stores an index referencing other control units for the other directory numbers. Advantageously, the control units referenced are not necessarily the same ones that are associated with the ports defined by those other directory numbers. Thus the call setup sequence frequently involves three control units-the units associated with the originating and terminating ports, and an intermediate unit which stores the directory number translation information for the received directory number.