Abstract: A removable disk cartridge for use with a rotary actuated disk drive includes an enclosure having a top, a bottom, and a side connecting the top and bottom. The enclosure has a cutout formed by removal of a portion of the top, removal of a facing portion of the bottom, and removal of a portion of the side connecting the removed top and bottom portions. A disk is mounted for rotation inside the enclosure. The disk is exposed at a top surface, a bottom surface, and an edge. A door is pivotally mounted on the enclosure. The door has a top surface to shield the top surface of the disk, a lower surface to shield the bottom surface of the disk, and a side surface to shield the edge of the disk. The door has a closed position to fully seal the cutout, and the door has an open position to fully expose the cutout. Access to the top surface, bottom surface, and edge of the disk is provided by the exposed cutout.

Abstract: A single Reed-Solomon code is employed with modifications to allow information systems the freedom of selecting redundancy from 1 to R symbols, where R is the number of redundant symbols that the unmodified Reed-Solomon code employs. If P is the number of discarded redundancy symbols, then R-P redundancy symbols are retained, and the minimum distance of the modified code is 1+R-P. The system uses one of several alternative decoding schemes. One general scheme employs error-and-erasure decoding, and treats the P deleted symbols as erasures. Another general scheme operates directly on the shortened, modified code-word and modifies both the error syndromes and the error information derived from the syndromes to compensate for the deleted symbols.

Abstract: A voltage level conversion buffer circuit including a first and a second transistor each having a gate, a drain, and a source. The drain of the first transistor and the gate of the second transistor are connected together to provide an input to the buffer circuit, and the gate of the first transistor and the drain of the second transistor are connected to a supply voltage. The sources of the first and second transistors are connected together to provide an output for the buffer circuit.

Abstract: A relational data access facility allows relation-type queries to access data stored in non-relational data files by converting relational queries into a set of common commands which are sent to data drivers to obtain the data specified by those queries. The facility uses metadata which describes the organization of the data in the non-relational files, and examines the expressions in the relational queries to formulate an access plan for the data. The plan is formulated to reduce cost and promote efficiency.

Abstract: A method and apparatus for prioritizing a plurality of incoming electronic mail messages for a user uses a user created and modified rules-control (12) which is stored in a rules-store (12). Incoming messages are stored in a message store (11) and are screened individually by a rules test unit (13). The rules-test unit has a comparator (52) which matches keywords which are chosen by the user while creating the rules, add supplies signals to an action list unit (54). By applying the user created rules for deciding which messages constitute the priority messages for the user, a priority assigning unit (45) within an action portion (35B) of the rules-store (12) assigns a priority number (say from 1 to 5, 1 being the highest priority for example) to each screened message. Responsive to the assigned priority number of the screened message, the message is sent to a main folder store or forwarded or put away as appropriate. The user created rules can be modified by the user using a conventional keyboard.

Abstract: A method and apparatus for writing and reading servo data placed on a plurality of disk surfaces to minimize the degree of overlap of headers written or read by each write/read channel. Time division de-multiplexing (selecting) the writing of servo data to disk surfaces from each write/read channel and time division multiplexing the reading of servo data from the staggered headers contained on the disk surfaces coupled to each write/read channel increases the number of surfaces written to or read in a single rotation by each write/read channel. Disk surfaces are coupled to the write/read channels in groups to minimize the number of rotations required to write to or read from all the surfaces contained in the groups. Groups of surfaces may be sub-grouped. The headers of sub-groups are interleaved so that portions of the header written in a separate disk pass whose length is less than half the total length of the header may be written or read in the same rotation as another group of surfaces.

Abstract: A frame assembly for rack-mountable components. A rectangular top frame having a tubular perimeter is connected by four vertical rails to a bottom frame which also has a tubular perimeter as well as tubular members which span it. Both and top and bottom frames each provide an unobstructed central area which may be used for ventilation or application of electromagnetic shielding.

Abstract: A protocol analysis system is provided with data specifying the defined states of processes participating in a distributed computation. State transitions between states are specified as being enabled by (A) receiving a message, (B) unreliably sending a message, or (C) performing an external action such as reliably sending a message. The specification data also identifies process states known to be final states, and all other states are initially denoted as intermediate states. The protocol analysis system determines if any intermediate states can be re-categorized as final states. Then it determines if any state transitions initially identified as unreliable send operations must be treated as derived external actions, and thus made reliable. Thirdly, for each derived external action, the states of the affected application process must be re-evaluated so as to determine if derived final states need to be converted into intermediate states.

Abstract: A magnetic tape recording system which achieves very high track densities through utilization of a recording method and apparatus. A magnetic head is described in which the read head gaps are parallel to but laterally offset from the write head gaps. A head assembly is further provided in which the magnetic head is mounted on a rotary motor for aligning the head for writing and reading tracks at different azimuth angles, as well as a stepping motor and linear actuator for stepping the head between tracks. Also, a servo tracking method and apparatus is presented in which writing and reading take place under servo control. This servo allows alignment of the write head gap during writing, and the read head gap during reading, through observation of low frequency servo data blocks dynamically imbedded amidst adjacent track data. The utilization of this servo minimizes tracking error due to lateral tape motion.

Abstract: A computer graphics method of and apparatus for normalizing vector-based terms for a plurality of display pixels associated with a polygon representing a surface of an object being imaged, the vector-based terms being determined from predetermined vectors at vertices of the polygon. The square (.eta.) of the magnitude of a vector associated with each vector-based term is determined for each display pixel from the predetermined vectors at the vertices of the polygon. The quantity 1/.sqroot..eta. is approximated for each vector-based term using a series expansion employing .eta., and each vector based term is multiplied by the corresponding approximation of 1/.sqroot..eta. to produce a normalized vector-based term for each display pixel.

Abstract: A method and system for compiling a source program using smart recompilation. The invention allows fragments to contain "invocation specific" information, which is generated during a code generation phase of compilation. A hint generator attempts to preserve values of the invocation specific information between successive invocations of the compiler.

Abstract: A "signature data object" (SDO) is a machine-readable structured data record which a signer may associate with a parent object, e.g., an electronic document. An SDO comprises three required encoded parts: A signature header structure; a signature data structure; and a signature proof block. An SDO may include data identifying a role in which the signer is acting and a message code encoding a semantic for the parent object/document such as "submitted by," "approved," etc. In one embodiment, the SDO includes at least one descriptor of (1) a subordinate part of the parent object or (2) an attachment of the parent object/document, to whose (i) value or (ii) presence the validity of the signature data object is bound. An SDO may also include data indicating that it supersedes a specified other SDO associated with that parent object.

Abstract: A three-port Josephson memory cell has one input port (a data line) and two output ports (first and second sense lines). The memory cell receives a write enable pulse on a write line to store a bit of data from the data line as circulating supercurrent. The memory cell also receives a first read enable pulse on a first read line to enable assertion of the stored data onto the first sense line, and receives a second read enable pulse on a second read line to enable assertion of the stored data onto the second sense line.

Abstract: An identification panel for a cabinet for electronic equipment, such as computers or computer peripherals. A back panel is mounted to an intermediate window and doorframe member having a control door frame, and a translucent window aligned with the back panel. The back panel may incorporate permanent identifying artwork for the equipment. This assemblage is accommodated in an opening of, and secured to, an external cover frame. The cover frame opening also accommodates a control panel door mounted on the intermediate window and doorframe member to cover the doorframe opening and slidable behind the translucent window to uncover the doorframe opening. The translucent window has a part-cylindrical convex surface which projects through the cover frame opening to provide a lens effect which enhances the visibility of artwork provided on the back panel.

Abstract: A method and apparatus for identifying and synchronizing to two different fields in a disk drive employs different synchronization or "sync" patterns to reduce the chances of mis-identifying and false-identifying a field. Two very distinct synchronization patterns have been found that satisfy the d=1, k=7 run-length constraints of a data code used in the disk drive. During operation, one sync pattern is searched for to identify and synchronize to its associated field, then the field itself is read. This procedure is then repeated for the other sync pattern and its associated field. Also, the phase of a preamble preceding each sync character is established, so that the number of comparisons needed to find either sync character is reduced. A sync detector operates on cell pairs, and has a selector that selects which sync pattern to search for. The sync detector also has special features that enable it to find preamble and DC Erase fields in the disk cell stream.

Abstract: In a system for compressing, decompressing, and logically manipulating arbitrary bit-maps, the bit-map is aligned along byte boundaries. Each aligned byte is classified as a gap byte if all of the bits of the byte store the same logical value, otherwise the byte is classified as a non-gap byte. Adjacent bytes of the same class are grouped. Groups of gap bytes are encoded into an atomic sequence of bytes as a count of the number of bits included in the grouped gap bytes. Map bytes are duplicated in the atomic sequence and also associated with a count thereof.

Abstract: Disclosed is an apparatus and method for processing electronic components in an ultrasonic bath. The apparatus includes a tray, which has a number of nests geometrically configured for the admission of the components. In one embodiment the tray is made of a polypropylene core which includes conductive carbon and glass beads as a filler. Plated over the core is a metallic sheath, which is actually formed of three layers of metal. The metal encapsulation of the core serves to appreciably reduce the amount of contaminants released by the tray during component processing. Additionally, the metallic sheath prevents static electricity from building up and damaging the components during processing, and provides added structural integrity to the polypropylene core at process temperatures which exceed the softening temperature of the core.

Abstract: An I/O bus interface cell includes a driver circuit having an input terminal fed by a logic signal and an output terminal to produce in response thereto a drive signal having selectable rise and fall time characteristics in accordance with a reference voltage provided to the driver. The I/O cell also includes a receiver circuit having an input terminal coupled to said output terminal of said driver with the receiver disposed to latch an unresolved, unamplified received signal prior to resolving the state of the signal. The I/O cell further includes a termination circuit having a terminal connected to the output of said driver, and having a selectable impedance characteristic at said terminal, with said selectable impedance being in accordance with a reference voltage provided to an input of said termination circuit. Preferably, the I/O cell the driver, receiver and termination circuits are fabricated on a common semiconductor substrate.