Abstract: A computer apparatus which detects a store or load operation into or from a shared memory page by a program that does not provide for synchronization when executed by a CPU that completes instructions out of program order. After the store or load is detected, the CPU explicitly orders operations into the shared memory page. Store operations are ordered such that no new store into the shared memory page is performed until all prior store operations into the shared memory page are complete. Also, load operations are ordered such that load operations from the shared memory page are performed in program order. This ordering is achieved by maintaining a process bit and a memory attribute bit associated with a shared memory page. When both bits are true, all load or store operations referencing the shared memory page are ordered.

Abstract: The present invention relates to the design of computer systems incorporating virtual memory where a virtual page number is longer than the inherent basic data width of the designed computer system. Instead of storing an entire tag in page table entries, a reduced tag is stored. The reduced tag is sized to be no greater in length than the basic computer data width and therefore a single compare operation will ascertain whether there is a match between the reduced tag and the tag stored in a page table entry. To maintain uniqueness of the page table entries, any bits removed from the virtual address to form the reduced tag are used to form an index into the page table.

Abstract: An apparatus and method for computing population counts of large bit strings. The present invention utilizes carry-save adders to reduce the time required to perform a population count on an operand in a register. Because carry-save adders do not propagate carries they are inherently faster than full adders utilized in the prior art. Additionally, the present invention implements a novel method for computing population counts whereby the operand bit string is split into smaller blocks and multiple partial population counts are performed. These smaller partial population counts require less time to compute than a full population count over the entire operand bit string.

Abstract: An operational amplifier with reduced bias circuit noise. The present invention reduces the noise contribution of the non-inverting input bias circuit. This noise reduction is accomplished by reducing the bandwidth of the bias circuit by bypassing high frequencies to signal ground. This reduces the noise voltage developed across the bias circuit and thereby reduces the noise at the output of the amplifier.

Abstract: An interchip high speed I/O circuit having a low voltage swing and on-chip transmission line terminations. The present invention provides a high speed I/O circuit that uses a small voltage swing to keep power dissipation in the overall system to a minimum and particularly in the transmission line termination loads. A differential receiver circuit compares a data signal input to a reference signal, both sent from a driver chip, to determine the appropriate output response. Both the data signal and the reference signal are current controlled which reduces the di/dt noise generated by parasitic inductances.

Abstract: A method and apparatus for encoding identification information into a stream of digital data representing an object. The digital data representing an object is modified to add embedded identification information into the data. This modification is done such that the resultant changes to the object are not objectionable to the user. By comparing the original digital data to the modified data, the possessor of the original data can recover the embedded identification information. However the identification information is effectively unavailable to anyone not possessing the original data.

Abstract: A fast cache hit detection method and apparatus. The present invention provides a method and apparatus for quickly determining whether there is a cache hit in cache memory systems utilizing error corrected tags. The hit detection process is split into two paths. The first path includes a circuit to check and correct a tag stored in the cache memory. The second path tests the validity of the tag stored in the cache memory by computing the appropriate ECC information using memory address information supplied by the computer CPU and comparing the tag and ECC stored in the cache memory to the CPU address and computed ECC. As the computed ECC is performed in parallel with the cache RAM access, this second path provides hit confirmation faster than the first path which must process the tag and ECC stored in the cache RAM through a ECC check and correction circuit. If a fast hit is confirmed, then the cache memory system can proceed to supply cache data to the CPU.

Abstract: A retaining clip to retain a circuit board insertion/extraction handle on a circuit board. The present invention is a retaining clip which is part of a circuit board inserter and extractor apparatus particularly suited for use with circuit boards utilizing high insertion force connectors requiring in excess of 50 lbs of force. The handle of the inserter/extractor has novel insertion and extraction surfaces which cooperate with corresponding surfaces fabricated as part of a card guide. As the circuit board is inserted into the card guide, the handle is automatically positioned so that the user can press the bottom of the handle to insert the circuit board. The handle and card guide interface is designed to provide a large positive force to extract the circuit board from the card guide until the circuit board is unseated from the associated high insertion force connectors. The clip is constructed of stainless steel and formed into a generally flat "U" shape.

Abstract: A portable computer convertible between using a keyboard or an electronic pen to input data is provided with an electronic pen holder. This pen holder rotates to provide easy access to the electronic pen when the computer is configured for either keyboard or pen input. In addition, the pen holder includes pen holding holes for storing the electronic pen vertically when rapid repetitive access to the pen is desired.

Abstract: An electrical interface connects a conductive pins to a printed circuit board. The electrical interface includes an elastomer holder having a plurality of holes. Elastomer conductors are placed in the plurality of holes within the elastomer holder. The elastomer holder is then attached to the printed circuit board so that each elastomer conductor comes into contact with a conductive pad on the printed circuit board. The conductive pins are placed in electrical contact with the elastomer conductors, for example, through a conductive socket. In the preferred embodiment the elastomer holder is composed of printed circuit board material. Before the elastomer holder is connected to the printed circuit board, the elastomer conductors are held in the holes in the elastomer holder using a throw-away retainer.

Abstract: The present invention provides a protocol method for waiting the bus in a digital computer and an apparatus for implementing that protocol. By allowing the bus to continue running after a wait command has been asserted, modules on the computer bus are not required to respond instantly to the wait command. Information on the bus during the multiple cycles of the wait period is defined as invalid and valid data is driven on the bus after the wait period has expired. Bus driver modules are provided with a replay queue to replay, on the bus, data the driver module drove on the bus during the wait period if required.

Abstract: The present invention provides a new and novel method for locking software programs to a particular disk. The method includes the steps of creating several files, one with a fixed name and at least one other file having a random name. Saving the head, cylinder and sector information for each of the files in the corresponding file along with use count information, saving the names of all the files in the first file with the fixed name, and encrypting all the files. This program locking method permits the distribution of trial copies of software programs and limits the risk that the program will be copied or used more than the permitted number of times.

Abstract: The invention is embodied in an articulated pawl. This pawl is designed to reliably drive a take-up reel on a tape and reel component feeder. By always engaging teeth on the reel, the pawl is prevented from skipping teeth during the return phase of the reel drive cycle. The addition of an articulated arm on the pawl prevents the pawl from skipping teeth on the reel during the drive phase of the reel drive cycle. The articulated arm ensures that either the tooth on the base of the pawl or the tooth on the articulated arm engages a tooth, or both engage teeth, on the reel during the drive phase. This invention ensures the positive and repeatable rotation of the take-up reel.

Abstract: The invention is embodied in a TAB frame with wide spaced area array contacts. The area array contacts serve to transform the narrow pitch contacts which connect to a chip mounted on the tab frame into wide spaced TAB edge contacts. These area array contacts allow for the convenient connection of the TAB frame to a printed circuit board and eliminate the need for fine line printed circuit board technology to support the TAB assembly.

Abstract: A semiconductor memory device is provided with a plurality of primary memory cell blocks and a replacement memory cell block identical in size to the primary memory cell blocks. The replacement memory block includes all the required analog row and column driver and sense circuitry for the memory cells contained in the replacement block. Each of the primary memory blocks has a laser fuse that will disable the associated primary memory block and enable the replacement memory block such that the total amount of logical memory in the memory device is unaffected by a defective primary block.

Abstract: A multiple chip module (MCM) is fabricated by connecting a series of semiconductor chips, in a flip-chip orientation, to a multi-chip substrate with resilient connection pads. The substrate is formed from silicon by placing a layer of SiO2 on the surface. At the locations requiring a resilient connection pad, the SiO2 layer is pierced with a series of closely spaced holes. A cavity is etched out of the silicon below the closely spaced holes. The SiO2 layer is now suspended over the cavity and forms a flexible membrane. A post is formed on top of the flexible membrane. A conductor formed on the substrate has one end supported by the post. One end of the conductor is, therefor, supported by the post and flexible membrane so that a solder bump placed thereon may be used for a demountable connection to a contact pad on a flip-chip.

Abstract: A grating tuned external cavity laser having improved mode selectivity and stability. A cylindrical lens is positioned between a laser amplifier and a prism pair beam expander to focus the laser beam to form a linear spot on a grating. The location of the cylindrical lens between the laser amplifier and the prism pair minimizes the optical length of the laser cavity. In this way, the wavelength separation between optical resonance modes is increased, and the mode selectivity and stability of the system is enhanced.

Abstract: The invention is embodied in a demountable TAB assembly. By using two springs in series, the present invention is able to maintain reliable contact between the TAB frame and the printed circuit board even if the elastomeric spring relaxes. The present invention also incorporates a novel TAB frame using contacts formed into an area-array. This area-array concept eliminated the need for fine line printed circuit board technology to support the TAB assembly.