Abstract: Engineering changes (EC) for an integrated-circuit (IC) module or circuits connected to an IC module sometimes require the addition of discrete electrical components or circuit chips. Such engineering changes are implemented herein on a small printed circuit card or board that may be physically attached to the top of the IC module. The EC pads on the printed circuit EC card are juxtaposed with the IC module input/output (I/O) pins that require the engineering change. A short fly wire is then soldered between each juxtaposed EC pad and the I/O pin to make the electrical connection between the EC card and the module. In this way, no additional surface area is consumed on the printed circuit board on which the module is mounted.

Abstract: Multiple versions of a given system command are run on a single operating system by using one command processing program per command irrespective of its version. Each version of the command has a command definition which has the same format for all counterparts of the command. A command analyzer program transforms the parameters of a command character string into the correct data form for its command processing program based on the command definition for that version of the command. Multiple sets of command definitions are place in separate storage directories called libraries. The libraries are searched based on a version identifier to find the command definition for a command. The version identifier may be specified as a program attribute, entered interactively or entered by the system. Multiple programs written with different versions of commands may be run in conjunction with each other and the system will dynamically adapt to the version of each program as it is running.

Abstract: A composite minimum-joint electrified rail is constructed by combining a non-conductive support rail divided into easily installed segments with a continuous conductive rail that mounts on the support rail and spans any number of support rail segments. The conductive rail may be attached to the non-conductive rail by a tongue and groove arrangement. Multiple conductive rails or strips may be attached to different portions of the same support rail. In addition spring clips are shown for attaching the support rail to railroad ties or roadbed, and fish plates are shown for attaching abutted support rails.

Abstract: A composite minimum-joint electrified rail is constructed by combining a non-conductive support rail divided into easily installed segments with a continuous conductive rail that mounts on the support rail and spans any number of support rail segments. The conductive rail may be attached to the non-conductive rail by a tongue and groove arrangement. Multiple conductive rails or strips may be attached to different portions of the same support rail. In addition spring clips are shown for attaching the support rail to railroad ties or roadbed, and fish plates are shown for attaching abutted support rails.

Abstract: A two axis electromagnetic actuator is designed for moving an optical element in an optical or magneto-optical recorder. The actuator has balanced, crossed, electro-magnetic coil structures supported by two sets of leaf springs and positioned in dual air gaps for motion in a direction which is the vector sum of the movement in two orthogonal directions. In the actuator the motive forces and the masses of the moving elements are centered on the axis of major motion. Also leaf springs, that allow the major motion, have their forces balanced about the axis of major motion.

Abstract: A method and apparatus is provided for characterizing magnetic coating compositions that contain magnetic particles dispersed in a solvent resin matrix. The coating composition, as it passes through a tube, is subjected to an alternating magnetic field and perpendicular thereto a constant magnetic field of appropriate field strength and duration. Via a measuring coil surrounding the tube the induced signal in the composition is monitored and the degree of dispersion, is measured by measuring the magnetic susceptibility of the coating material. By applying a constant magnetic field the degree of dispersion cna be changed at least for a certain time. The method and apparatus of the present invention can be incorporated into a coating apparatus to monitor and improve the magnetic characteristics of the coating material being applied to a substrate.

Abstract: Width restoring to eliminate unintended width variations in pulse width modulated data in combination with a phase lock loop allows pulse width modulated data in high density optical recordings. The width restoration is accomplished by detecting the timing relationship of the leading and trailing edges of pulses relative to expected timing for the leading and trailing edges. Expected time is derived from a phase locked loop or the original write signal. The detected timing is compared to the expected timing and the timing of the leading and trailing edge signals is corrected. Either analog or digital width correction techniques are used. Width restoration may be used while reading data or while writing the data.

Abstract: A method for forming a master mold for optical storage disks includes thermally growing an oxide or nitride layer on a semiconductor wafer. The thermally grown layer is then coated with a photoresist. The photoresist is exposed to a laser beam to form a data pattern and developed. The oxide or nitride under the developed pattern is etched and the photoresist stripped to provide a semiconductor master mold for optical disks.

Abstract: A two axis electromagnetic actuator having balanced crossed coil structures supported by two sets of leaf springs and positioned in dual air gaps for motion in a direction representing the vector sum of the movement in two orthogonal directions.

Abstract: An optical file system in which a command to store data results in a write operation in the next available storage position. A single optical path is used for both reading and writing. By dividing the detector in two equal parts along the direction of relative movement, it is possible to determine whether data has been written at a position which is in advance of the center of the area viewed by the detector. The write operation is conditioned on the output of the first part of the detector. Since the first part of the detector gives advance warning on the status of the oncoming data position, it is possible to switch from reading to writing without the requirement for a wasted revolution or wasted space. By dividing the signal resulting from a change of reflectance sensed during a write operation by a measure of the intensity of the write laser a read signal free of the write modulation is obtained.

Abstract: A phase retardation element, for use in an optical data storage system, which provides a 90.degree. phase difference between two perpendicular polarized components of an incident wave with a single internal reflection from a surface coated with a thin film of dielectric or metal material.

Abstract: Bandpass filters are used to sample the output signal from the equalizer. These samples are amplified in variable gain amplifiers and summed with the input signal to achieve equalization. The amount of gain applied to each sample is based on the difference between each sample's magnitude and a reference signal. In one embodiment, the reference signal is derived from the adjacent bandpass sample. In another embodiment, one bandpass sample is the reference for comparison with all other samples. In the third embodiment, bandpass filters are also connected to the input signal in order to achieve a feed-forward rather than feedback configuration for the equalizer. In all of the embodiments, the magnitude signals from the bandpass samples are weighted before being compared to the reference signal. The weighting factors allow the filter to be designed for a desired transfer function and adapted to an input signal spectrum.

Abstract: Cascaded programmable logic arrays are used to program any type of flip-flop. The latch itself can be embedded in the array when using cascaded PLA's. The arrays can be cascaded to provide logic functions using less total area than a single array embodying the same function.

Abstract: Error information is passed across a limited interface from a disk drive to its using system by making use of the read data line during a fault mode operation. Fault mode operation is detected by a pulse width detector in an adapter between the using system and the disk drive. The pulse width detector detects the presence of a fault signal on the read data line and inhibits the passage of the spindle motor on (MTR ON) signal from the using system to the disk drive. The step signal normally used to index the recording head is passed to the disk drive during fault mode operation. A microcomputer at the disk drive detects the absence of the MTR ON signal and the presence of the step signal and outputs a fault data bit. Thereafter, the fault data word is gated onto the read data line at the rate of one bit per step of the step signal so long as the MTR ON signal is absent.

Abstract: The diskette drive described herein reads and writes information on a flexible magnetic disk stored in a rigid diskette cartridge. The drive contains apparatus for loading and registering the cartridge in the drive without the assistance of a loading tray or cartridge carrier. The disk drive spindle, the recording head and cartridge position registration pins all protrude into the insertion path for the cartridge. The spindle and pins are shaped and positioned so that the cartridge will not strike the recording head as it is inserted. Spring fingers are provided to bias the cartridge down against the spindle and the registration pins. When the cartridge is fully inserted, it snaps into a registered position over the pins, the spindle and the recording head. In addition the cartridge contains a truncated corner that cooperates with a blocking member in the insertion path to prevent the cartridge from being improperly inserted.

Abstract: Optimal reservoing times of an ink jet printer are determined to be when an optimal time period exceeds a fixed maximum value, where the optimal time period is proportional: to the time since last reservoing, to the usage, and to the square of temperature changes. Specifically, the optimal time period, t-opt, ist-opt=T+mC+kKKwhereT=time since last reservoing,C=usage value,K=temperature changes, andm,k=empirically-determined constants.

Abstract: In a data processing system, data is transferred between a plurality of functional devices through a shared memory without the intervention of the processor. The data transfer is controlled by a Shared Memory Access Channel (SMAC) having a pointer table storing memory addresses to control shared memory accesses and by the functional devices using device addresses, pointer identifers, indicating the pointer to be used from the pointer table, and control codes. The control codes used in the transfer include a Post code (P code), an Available code (A code) and an End of Process Code (E code). The device, from which data is transferred, is referred to as the upstream device, and the device to which data is transferred is referred to as the downstream device. The P code tells the downstream device that the upstream device has written a predetermined amount of data into a shared buffer area in the memory.

Abstract: The digital-to-analog converter described herein generates an analog signal level from a digital value and a modulation coefficient. The converter modulates the digital word applied to the conversion stages and smoothes the resultant duty cycle modulated analog levels to produce additional analog levels between the normal levels provided by the conversion stages of the DAC. In one embodiment the duty cycle modulation of the digital value is accomplished by a rate multiplier controlling the incrementing of the digital word applied to the conversion stages. In another embodiment of the invention, the duty cycle modulation of the digital word is performed by a microcomputer. A low pass filter or a DC motor is used to smooth or filter the duty cycle modulated levels from the conversion stages.

Abstract: A peripheral processing controller controls time-shared access to a memory by specialized peripheral devices. The specialized peripheral devices process data independently of a central processor that simply supervises the system. The peripheral processing controller uses predetermined modes of memory space allocation for the various peripheral devices. A memory address register in the controller is assigned to each peripheral device. In addition, each MAR has one or more predefined modes of memory space allocation and, when active, controls memory access for its assigned peripheral device. The modes also define the size of the block of space allocated and whether memory access scrolls through various blocks of space or jumps between blocks of space. The controller also detects when a peripheral device has consumed all the space in a block.

Abstract: Printer having a sheet feed and drum transport assembly, an exit assembly and at least one dryer. Various print parameters or conditions are monitored relating to the drying of the ink on print media. These print parameters include print data density, ink characteristics and ambient humidity. The monitored print parameters are used to control the drying. In addition the monitored print parameters are used to control the detaching of the print media from a rotary transport. In this manner, the printer approaches an optimization of the drying and detaching function with respect to time and energy.