Abstract: In a distributed network comprising a plurality of peer (as opposed to master-slave) computers, a method of file shadowing allows each peer computer to maintain copies of data entries originated by the other peer computers in near-real time. Each computer assigns a unique serial number to each entry, and forwards each entry with the serial number and an identification of itself to all the other computers. Each computer informs each other computer of the highest sequential serial number received from it, and each computer resends to each other computer all entries having serial numbers higher than that acknowledged by each other computer.

Abstract: In a distributed computer network having a large number of intercommunicating distributed nodes and a smaller number of control nodes in which each distributed node reports status information to a particular one of the control nodes, a method is provided for guaranteeing that at least one control node receives a status message from a distributed node despite the unavailability of the particular control node to which the distributed node normally sends its status messages. Each distributed node associates a serial number and time stamp and an identification of itself with each message it originates, and each distributed node retains copies of the messages. Should a distributed node be unsuccessful in transmitting to its normal control node it attempts to transmit to other control nodes until it transmits successfully.

Abstract: A personal computer (PC) operating with terminal emulation software as a terminal to mainframe host computer has means for dynamically reordering the programs it runs other than the terminal emulation software. It has provision for receiving program names from the host computer and for running the programs so specified without operator intervention. It may then re-enter the terminal emulation software, again without operator intervention.

Abstract: A data processing unit includes a number of tightly coupled central subsystems, a number of peripheral subsystems, a main memory and a system management facility all coupled in common to a system bus. The system management unit has top priority on the system bus and includes centralized resources which provide apparatus for indicating the status of power and temperature, booting the subsystems, testing the subsystems, timing central subsystem functions, and allowing local and remote maintenance access to the subsystems. The system management facility receives commands from the central subystem to read from and write into the timers as well as to read the status of the overall system. The system management facility generates special commands to the central subsystem to indicate when the timers have decremented to ZERO as well as special commands to aid in hardware and software debugging.

Abstract: The subject invention is directed to a database system for organizing large amounts of data to be accessed by a digital computer. More particularly, a free form type database, in the form of a summarized, multikey tree, is built from files stored on the computer. After a building operation, the user obtains specified information by using the summarized database. Information in the files is divided into three categories; that is, a dimension field which comprises data to be organized, a summary field which comprises a numeric quantity on which calculations can be performed, and a non-summary field which comprises other information associated with an input record. The internal nodes of the tree summarize and organize sets of input records. Methods are provided for reducing the amount of storage space used by cutting off the tree when the size of sets go below a given threshold, and sharing parts of the tree so that each record does not appear n! times in the database.

Abstract: Classification of natural language data wherein the natural language data has an open-ended range of possible values or the data values do not have a relative order. A training database stores training records, wherein each training record includes predictor data fields. Each predictor data field containes a feature, wherein each feature is a natural language term, and a target data field containing a target value representing a classification of the record. Features may also include conjunctions of natural language terms and each feature may also be a member of a category subset of features. The training database stores, for each feature, a probability weight value representing the probability that a record will have the target value contained in the target data field if a feature contained in a corresponding predictor data field occurs in the record.

Abstract: In a data processing system, a data processing unit contains data processing logic including shadowed functional registers for storing the data being processed. The units also include fault monitoring logic, including, for each shadowed functional register, a shadowing copy register connected in parallel from the corresponding shadowed register to receive and store a copy of the data resident in the shadowed register. Test logic is connected from the shadowed and shadowing registers for comparing the data resident in the shadowed and shadowing registers and providing indications of possible faults in the data processing logic. The shadowed and shadowing registers are connected in a serial scan chain through a serial scan data path. The integrity of the fault monitoring logic is tested by serially shifting, or scanning, known test patterns of bits through the serial scan chain comprised of the shadowed registers and shadowing registers.

Abstract: A monitor for selectively detecting and recording conditions at selected points within a system during operation includes trigger logic connected from first selected points and responsive to selected conditions occurring at each of the first points for generating corresponding trigger outputs representing the occurrence of the selected conditions and a silo bank memory having a sub-silo for each second point. Each sub-silo has a first sub-silo segment with data inputs connected from the corresponding second point for recording data from the second point and a second sub-silo segment with data inputs connected from a time stamp generator.

Abstract: Memory retry logic to improve the resilience of system memory operations with respect to system errors or faults which prevent a memory read operation from being completed on a first attempt by allowing the memory to retry the operation once. The memory retry logic detects the occurrence of an improper response from the system element requesting a memory read operation when attempting to initiate the system bus operation for reading the data from memory to the requesting element and, if an improper response indicating that the requesting element is not accepting the bus operation request is detected, stores the memory operation request and the requested data and retries the data transmission on the next available bus cycle. If the memory receives an improper response of a specified type during a bus operation of a memory burst, the memory will terminate the operation and proceed to the next requested operation.

Abstract: A monitor device for selectively detecting and recording conditions at selected points within a system during operation, including a trigger enable memory for storing selectable trigger enabling codes wherein each code corresponds to a trigger signal representing the occurrence of a corresponding condition to be detected, a trigger generation device connected from first selected points and responsive to selected conditions thereupon for generating the trigger signals representing the occurrence of selected conditions, a trigger output device responsive to the enabling codes and the trigger signals for providing trigger outputs upon the occurrence of a trigger signal corresponding to a selected trigger enabling code, and a silo bank memory connected from second selected points and responsive to the trigger outputs for recording conditions present at the second points.

Abstract: A means for ascertaining the health, or basic operational status, of a system unit. A "health check" provides an indication of either "yes", the system unit is operational, or "no", the system unit is either inoperative or there is a question as to whether the system is operational. The test is performed by requesting that the system unit perform a high priority "short" operation and noting the response provided to the request; the actual execution of the request is unimportant and it is the response of the unit under test to the receipt of the request for a bus operation that is the actual indicator of the status of the unit being tested. The requested operation is not directed at the unit whose operational status is to be determined, but instead at a bus interface unit which performs bus operations for the unit to be tested and whose responses to requests for bus operations are effected by the operational status of the unit that is to be tested.

Abstract: A monitoring means for selectively detecting and recording signals representing at selected points within a system, includes trigger generation logic responsive to selected bus signals for generating trigger signals representing the occurrence of selected conditions, and a recording memory for recording the conditions thereupon, a trigger selection logic for selecting trigger outputs corresponding to the trigger signals. The trigger selection logic includes a trigger enabling memory for storing selectable trigger enabling codes, wherein each enabling code corresponds to a trigger signal, and trigger output logic responsive to the trigger enabling codes and to the trigger signals for providing trigger outputs. The trigger enabling codes include bus enabling codes representing selected conditions on a bus of the system, trigger sequence enabling codes corresponding to sequential combinations of trigger signals and external trigger enabling codes corresponding to triggers external to the system.

Abstract: A method and apparatus for resetting memory state when power is applied to the system. The memory has memory elements, a refresh clock and a refresh counter for counting refresh cycles and providing refresh signals to the memory elements, the memory elements and refresh means being connected from the power system and from a battery back-up means. A state detection means is connected from the refresh counter for detecting a change in state of the refresh counter to a state equivalent to the reset state of the refresh counter and asserting a state change signal. A means responsive to the state change signal and to the occurrence of the reset signal provides a memory controller reset signal, so that the memory controller reset signal occurs in synchronization with the change of state of the refresh counter to a state equivalent to the refresh counter reset state.

Abstract: A data processing system includes at least one modem connected from a communications link to the remote devices and at least one modem controller. A modem adaptor stores scripts for directing modem control related operation, each script being a sequence of links and each link directing a modem control related operation, a library of modem control subroutines, each subroutine corresponding to a link, and a link table relating each link to the corresponding subroutine. There is a set of scripts for each type of modem connected to the system.

Abstract: A prefix index tree structure for locating data records stored through keys related to information stored in data records. Each node includes a prefix field for a prefix string of length p of the longest string of key characters shared by all subtrees of the node and a data record field for a reference to a data record whose key is completed by the prefix string. A node may include one or more branch fields when the prefix string is a prefix of keys stored in at least one subtree of the node, with a branch field for each distinct p+1.sup.st key character in the keys, wherein each p+1.sup.st key character is a branch character. Each branch field includes a branch character and a branch pointer field for a reference to a node containing at least one key whose p+1.sup.st character is the branch character. Each node further includes a field for storing the number of key characters in the prefix string and a field for storing the number of branch fields in the node.

Abstract: A data processing system includes cache memories for storing instructions and operands. An execution unit stores instructions in an instruction FIFO, operands in a data FIFO and offsets in an offset FIFO. Offsets indicate the location of operands relative to a memory word boundary. Instructions read from the instruction FIFO are applied to a control store subsystem which reads out a firmware word. Specified firmware bits condition multiplexers in the data path to align the operands on the fly during the execution of the instruction.

Abstract: A parallel computer comprised of a plurality of identical processors, each processor having control and data inputs and outputs for communication with the host computers and separate interprocessor inputs and outputs for communication between the processors. The processors are permanently interconnected through interprocessor communications routers into a first, single n-cube array for purposes of interprocessor communication. The data and control inputs and outputs of the processors are separately connected in parallel to the host computers through a resource allocation means to divide the first, single n-cube array of processors into a multiplicity of smaller second arrays controlled by selected ones of the host computers.

Abstract: A method for performing initial testing of a system wherein, in response to power on of the system, the control store of a central subsystem is loaded with a testing microinstruction program for internal testing of the central subsystem and the testing program executed. Upon completion of the testing program, the central subsystem operating programs are loaded into the control store, and control of the data processing system is transferred to the system programs.

Abstract: A monitor for selectively detecting and recording conditions at selected points within a system includes a trigger memory for storing patterns of trigger signals, wherein each pattern of trigger signals corresponds to a selected condition to be detected on first points of the system. The trigger memory includes a first port having a read address input connected from the first points and a data output connected to trigger output logic for providing patterns of trigger signals corresponding to the conditions to be detected. Each pattern of trigger signals is stored in the trigger memory location whose address corresponds to a pattern of signals from the first points representing the corresponding condition to be detected. The trigger memory is a dual port memory having a second port with a write address input and a data input for receiving trigger patterns to be stored therein.

Abstract: A dust containment cap for use in a printing device to be supplied with finely pulverized toner which is susceptible of becoming airborne and contaminating surrounding areas employs two brushes arranged in the toner supply opening such that they completely fill the opening but permit the insertion of the neck of a toner bottle to be inserted through them for depositing new toner. Toner that becomes airborne below the brushes is impeded by the brushes from escaping from the opening. The brushes may be installed at downward angles so that together they form a "V"; toner inadvertently spilled on the tops of the brushes gravitates to the bottom of the "V" whence it may be dropped through by agitating the bristles.