Abstract: A digital data processing system comprises a host information generating device, a mass storage subsystem, and a back-up information storage subsystem. The host information generating device generates information and provides it to the mass storage subsystem for storage. The mass storage subsystem receives the generated information from the host information generating device and transfers the generated information to the storage element for storage, and further transfers the generated information to the back-up information storage subsystem. The back-up information storage subsystem receives and stores the generated information from the mass storage subsystem's control element. The back-up information storage subsystem includes a filter/buffer module, a tape log module and a reconstruction module. The filter/buffer module filters and buffers the information received from the mass storage subsystem and provides the buffered information to the tape log module for storage.

Abstract: A digital data storage subsystem comprises a cache memory, a digital data store and a host adapter. The cache memory includes a plurality of cache slots, each of which caches digital data from the digital data store for access by the host adapter. The digital data store includes a disk drive, in which data is stored in the form of variable- or fixed-length records. The storage controller identifies one of said data storage sections as constituting a current owner of respective ones of the cache slot, and is responsive to record staging requests to selectively transfer records from the data storage section identified as the owner of said at least one cache slot to said cache slot for caching. In staging records for the current owner, the storage controller may, but need not, over-write records that were previously staged in the cache slot for previous owners.

Abstract: A network navigation and viewing system is disclosed for use in managing a network. The network includes a plurality of digital devices interconnected by communication links in at least one domain, with each device having a device identifier and each domain having a domain identifier. The network navigation and viewing system facilitates generation of a graphical image depicting a logical organization of the network. The network navigation and viewing system in one aspect retrieving device identifier and domain identifier information for the devices connected in the network and uses them to generate a network organization graphical image for display to an operator, the image comprising a plurality of icons each representing a device, with the icons being aggregated in the network organization graphical image by domain thereby to depict the logical organization of the network.

Abstract: A virtual file system accessing subsystem is disclosed for use in connection with a computer system connected in a computer network. The computer system runs a selected operating system, such as Microsoft's MS-DOS and Windows operating systems. The virtual file system accessing subsystem facilitates the accessing of a virtual logical storage device that is identified by a virtual logical storage device identifier and that has a virtual logical storage device file system that includes at least a portion of a remote file system maintained by another device connected in the computer network. The virtual file system accessing subsystem comprises an operating system request redirector for enabling the operating system to direct access requests from an application program which identify the virtual logical storage device to a remote access element for processing.

Abstract: A processor processes a segmented to linear virtual address conversion instruction to convert segmented virtual addresses in a segmented virtual address space to a linear virtual address in a linear virtual address space. The segmented virtual address space comprises a plurality of segments each identified by a segment identifier, each segment comprising at least one page identified by a page identifier. The linear virtual address space includes a plurality of pages each identified by a page identifier. In processing the segmented to linear virtual address conversion instruction, the processor uses a plurality of segmented to linear virtual address conversion descriptors, each associated with a page in the segmented virtual address space, each segmented to linear virtual address conversion descriptor identifying the page identifier of one of the pages in the linear virtual address space.

Abstract: A printer unit for selectively printing on documents fed between a matrix printer and a rotatable inked platen. The platen is actuably movable between a retracted position and an advanced print position. The document while being printed upon is moved at the same speed as the velocity of the periphery of the rotating platen. The document feed is limited by a feed control roller cooperating with a pressure roller. The feed control roller is coaxial with the rotatable platen and is adapted to move therewith between the retracted position and the print position. A solenoid is provided to move the feed control roller and platen between the two positions. The documents are permitted to pass through the print station unimpeded when the roller platen and feed control roller are retracted.

Abstract: A document transport apparatus for serially transporting sheet material over a preselected transport path including an endless belt having a resilient compressible tubular base member and gripping members projecting therefrom. The gripping members are normally closed when the base member is uncompressed. The apparatus further includes pulleys at opposite ends of the transport path, the belt being entrained in the grooves of the pulleys. The grooves are dimensioned to compress the portion of the base member entrained therein, thereby opening the gripping members projecting from the compressed portion of the base member, permitting insertion or removal of a document. The belt grips the document and carries it along with it in the space between the pulleys.

Abstract: A document feeding apparatus is provided which includes a hopper for holding a stack of documents edgewise, feed means for serially removing documents from the hopper, and a follower or pressure flag for biasing the stack towards the feed means. Augers are disposed within the hopper adjacent the feed means for advancing the stack thereto, and for aligning or jogging the documents in an intermediate area thereof. The diameter and pitch of the threads of the augers increase from leading ends thereof towards their center sections, and decrease from the center sections towards the trailing ends thereof. The narrow-pitched threads at the leading ends of the augers serve to divide the document stack into packs. The widening pitch of the augers allows the documents to spread apart in the center sections, thereby reducing interdocumental pressure and friction and allowing the documents to be jogged and properly aligned relative to the base and a front edge guide of the hopper.

Abstract: An electrostatic dot matrix printer includes a print head utilizing a self-scanning ion charge transfer system to reduce the number of dot drivers and the operating potential required for electrostatic printing. In the print head, ionization is transferred from a set of scanning anodes to a set of apertured cathodes in a cyclical aperture-by-aperture fashion. In synchronism with the cylical transfer a selected pattern of ionization is transferred from the apertured cathodes, to a set of printing anodes. The selected pattern of ionization is further transferred to a portion of electrostatic paper by a planar electrode, thereby depositing a selectively determined charge pattern on the electrostatic paper.

Abstract: An electromagnetic circuit for controlling the travel of a stylus by attaching the stylus to a movable core. The movable core cooperates with a drive coil to form a magnetic circuit with annular portions extending into the drive coil from both ends thereof.