Abstract: In a data processing system having an electronic mail system for sending documents from a first user to a recipient user and, for each user, a means for creating and editing documents, the documents having differing formats, a method for converting a document having a first format into a document having a second format preferred by the recipient user, using a table of user document format preferences and a document format conversion facility. The user preference table contains, for each user, an entry specifying the document format preferred by the user, and appended to each document to be sent to a recipient user is a tag which includes a field specifying the user to receive the document, and a field specifying the first format of the document.

Abstract: A virtual memory unit (VMU) includes a state machine for controlling its operations in response to commands received from another unit. The state machine includes a plurality of programmable array logic (PAL) devices which are connected to gather status from the different sections of the unit. The outputs of the PAL devices connect in common and supply a first address input to an addressable state memory. The state memory includes a plurality of locations, each of which stores a binary code defining a different machine state. The state memory locations are accessed as a function of the status signals and current state and used in turn to generate the required subcommands for executing the received commands. The state machine makes it possible to easily classify the received commands to their complexity and urgency in terms of their effect on overall system performance.

Abstract: A queue manager for controlling the execution of requests for the transport of messages from users to destinations. Each request includes a message and an identification of a destination. The queue manager includes a queue for storing pending requests and a dispatcher task for creating a worker task to execute each request and provides a method for adapting the execution of requests to constraints and characteristics of destinations and communications links.

Abstract: In a distributed, multi-node system for communicating between a plurality of distributed terminals and one or more central computers, some of which specify command and control information to the nodes, intelligent means are provided in the nodes to enable the nodes to test their internal communication channels and the communication channels to their associated distributed terminals independently of the central computers, and to reconfigure themselves independently of the central computers, substituting spare channels for identified malfunctioning ones. Conditions detectable by or within the node may initiate such testing. This means comprises a script interpreter which causes the node to execute scripts previously provided to it. New scripts may be provided to the nodes from a central computer.

Abstract: A protection mechanism includes means for taking an input binary value and generating a unique key value as well as performing the reverse operation of taking a key value and generating an input binary value. The mechanism includes a scrambler which includes an array having a number of multibit container locations for storing a unique sequence of random numbers. The scrambler forms another binary value by rearranging the bits of the input binary value as a function of the random number values in addition to altering the states of such bits as a function of the random number values and the numeric bit position values of sources of the input binary bits. The resulting binary value is applied to an alphanumeric encoder which converts the binary value into a series of alphanumeric characters containing a valid key value.

Abstract: The arithmetic processor of a digital computer system has means for performing, on its output operands while they are in transit to memory for storage, such manipulations as operand alignment, conversions between packed and zoned format, insertion of signs, and insertion of predetermined characters for edit functions. Two registers are provided, each having a capacity equal to that of a memory word. Each register is provided with segmented input selection means for selecting from among calculation results, residual data retained from operand fetching, signs, and constants. The two registers are OR'd together to produce desired words for storage in the system's memory.

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 system includes a number of subsystems coupled in common to a system bus. The subsystems communicate with each other by sending commands to each other via the system bus. Channel numbers identify the subsystems. One subsystem includes apparatus for receiving commands requiring a priority interrupt by storing vectors in a random access memory. These vectors which are addressed by the channel number of the interrupting subsystem indicate the offset to be added to the base address of an exception vector table. The exception vector stores the starting address in a memory of the requested interrupt routine.

Abstract: In a distributed data system in which processes running in trusted systems whose results may be proprietary or sensitive in nature may be invoked by operators at remote, untrusted workstations, and in which said processes are provided with locks which do not permit proprietary or sensitive actions unless a request includes a key matching the lock, a method of associating keys with operators is based on each operator's presenting his ID and a valid password at the workstation at the time he logs on to the system, verifying his password in a trusted system, correlating his ID with a role or group of roles he is authorized to fulfill, and retrieving and storing in the memory of the trusted system, associated with the operator's ID, a list of keys (a "keyring") for each of those roles. The operator's ID is appended to every request he invokes, a process containing a lock interrogates the stored list and will not grant a proprietary action unless the stored list contains a key matching the lock.

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: In a distributed data system serving a large geographical area and having several network management systems, each for managing system components in a portion of the geographical area, the system including a number of workstations at which administrative commands for configuring or monitoring the network may be entered, each network management system and each workstation hosting a number of software processes, a method is provided of routing messages to processes as a function of the process name and the portion of the geographical area in which it has effect. This method facilitates reconfiguring network management systems to take over the functions of a failed network management system in a manner transparent to operators and administrators at workstations.

Abstract: Electrophotographic developing apparatus including a carrier of latent image formed on a photoconductive layer superposed to a conductive layer, a carrier of developing material juxtaposed to the latent image carrier at a developing zone for transferring the developing material on the photoconductive layer in a configuration corresponding to the latent image and a transfer station in which a printing support is brought in contact with the photoconductive layer for transferring the developing material from the photoconductive layer to the printing support, the distribution of the developing material on the photoconductive layer being enhanced by subjecting the photoconductive layer, in a zone extending between the developing zone and the transfer station, to an alternating electrical field which enables migration of developing material particles from the outside of the latent image to the inside of the latent image.

Abstract: A multiprocessor system has distributed shared resources and dynamic global data replication in which a plurality of processors communicate each with the other through a system bus. Each CPU is provided with a local memory for storing data used locally and global data shareable by a plurality of processes operative in different CPUs and therefore replicated in the local memory of each CPU. Global data replication is performed at page level only when a global data page is effectively needed by a plurality of processes operative in different CPUs so that memory space required for replication is minimized as well as traffic on the system bus for global data replication and global data writes required for ensuring global data consistency.

Abstract: In a multiprocessor system having global data replication in each of the local memories, each associated with one of the processors, the global data allocation in the several local memories is performed by translating global data logical addresses into addresses conventionally defined as real, the translation being performed by a first translation unit associated with and managed by the processor which generates the global data. The first translation is followed by the translation of the real address into a physical address generally differing for each local memory and performed by a plurality of translation units, each associated with one of the local memories and managed by the processor associated with that local memory.

Abstract: A multiprocessor system includes a plurality of central subsystem (CSS) units, a plurality of memory units and input/output units which connect in common to a system bus for transferring requests between a pair of units on a priority basis defined by a distributed bus priority network included as part of the system bus. A private bus (P bus) connects all of the CSS units and memory units in common for high speed block data transfers. Each CSS unit includes input circuits which couple to the priority network for detecting when the system bus is in an idle state. P bus logic circuits couple to the P bus and generate a transfer request in response to a request from its CSS unit only when the P bus is detected to be in an idle state. The idle signals from both buses are used to generate a system bus request for P bus access only when both buses are in an idle state so as to eliminate the need to contend for system bus use.

Abstract: A method and apparatus pertaining to a firmware control unit for detecting when such control unit is not behaving properly. The control unit is organized to include in each location of the unit's control store, to which control is not expected to transfer, a predetermined type of pattern containing an address specifying the address of that location, a suitable tag identifying the probable reason for the unexplained jump, and a transfer of control to the appropriate entry point in a reporting firmware routine within the control store. The reporting firmware routine has a number of entry points for collecting all the executions of unexpected locations and for storing the appropriate address and tag information in a predetermined register file for later referencing by an unusual event (UEV) handler routine.

Abstract: A multiprocessor system includes a plurality of identical central subsystem (CSS) units, a plurality of memory subsystem units and input/output units which connect in common to a system bus. Requests are transferred between a pair of units on a priority basis defined by a distributed bus priority network included as part of the system bus. Each CSS unit includes cycle stealer logic circuits which grant bus cycles on a round robin basis. The cycle stealer logic circuits are connected to receive high priority request signals from the network and refuse acceptance of a cycle granted to such CSS unit as a low priority requester thereby passing it along to a next lower priority CSS unit.

Abstract: Overflow detector connects in parallel with a shifter to receive the bits of an operand to be shifted for detecting an overflow condition by defining the location of the operand sign bit and detecting a predetermined change in operand bit position value. The detector generates a binary value indicating the bit position where the change occurred. This value is then compared with a value designating the number of shifts to be performed on the operand by the shifter. When the number of shifts is greater or equal to the binary value denoting the bit position, the detector signals the presence of an overflow condition.