Abstract: A method of transferring data between a data supply and a disk having a track divided into sectors, each sector having an address recording area followed by a data recording area. The method includes detecting a defective area on a data recording area; writing an address of the defective area on the corresponding address recording area; recording data on the data recording area by detecting the defective area with the address and writing part of the data on the data recording area up to the defective area, and writing the remaining data on the data recording area succeeding the defective area; and retrieving the written data by reading the address of the defective area and then reading the recorded data. The apparatus includes a circuit to record a test pattern on the disk, a circuit to sense the recorded test pattern and provide an address of a defective area, a circuit to write the address on the address recording area, a circuit to write data on the disk, and a circuit to read the recorded area.

Abstract: For use in an impact printer having a movable carriage, a motor supported by the carriage and including a rotatable shaft, and a drive coupling member affixed to an end of the shaft, apparatus is provided for loading a print wheel contained in a cartridge onto the drive coupling member in order for the print wheel to be rotated by the motor. The apparatus includes a support member mounted to the carriage for movement therewith. A guide member is mounted to the support member for movement generally parallel to the axis of rotation of the shaft between first and second positions. The guide member is adapted when in its first position to engage and guide the movement of a print wheel cartridge along the guide member in a direction generally transverse to the axis of rotation of the shaft.

Abstract: A serial printer for printing information on a record material is disclosed. The printer includes a frame and a platen mounted on the frame for rotation about its axis, the platen capable of supporting and advancing record material through the printer. A carriage assembly is also included and has a printing member supported thereon, the carriage assembly being supported for movement along a printing path adjacent the platen. Further, a motor is mounted on the frame and means are included for converting the rotary motion of the motor to movement of the carriage assembly along the printing path, the converting means including a cable mounted at either end to the frame. Additionally, means are included for maintaining a substantially constant tension on the cable, the tensioning means including means coupled to an end of the cable for automatically taking up slack in the cable caused by stretching or wear of the cable.

Abstract: Apparatus for feeding marginally punched record material comprises a main support member, and a plurality of drive pins mounted to the main support member for movement along a predefined path past a first location at which record material is inserted into the apparatus. Means included on the main support member adjacent the first location facilitates the buckling of record material inserted into the apparatus in a direction away from the pins during movement of the pins along the predefined path when there is no initial engagement of a pin with a marginal opening of the record material. When a pin thereafter moves into substantial registration with a marginal opening of the record material, the natural bias of the buckled portion of the record material in the direction of the pins will return it to a substantially unbuckled state to thereby engage the pin with the opening.

Abstract: An electronic image processing system includes a controller for receiving character font data from a main memory and for converting it to image data utilizable by a raster output device capable of formatting the image data in a plurality of scan lines onto an imaging medium. The controller includes an input memory coupled to the main memory for receiving character font data therefrom, a data pattern memory for providing a predetermined pattern of data in response to a predetermined address signal, and a plurality of band buffer memories each capable of storing image data representing a predetermined number of scan lines constituting an image band, each band buffer memory having enable input lines and associated data input lines. The input memory is addressed to access character font data therefrom, such accessed character font data being then applied to respective enable input lines of a selected one of the band buffer memories.

Abstract: A phase-locked loop circuit includes a voltage controlled oscillator responsive to a control voltage for generating a periodic first output signal comprised of pulses occurring at a first frequency determined by the value of said control voltage. In response to the first output signal, a periodic feedback signal is generated comprised of pulses occurring at a second frequency which bears a predetermined relationship toward the first frequency. In response to the feedback signal and to a first input signal having a first periodic interval during which pulses at a third frequency occur and a second periodic interval during which said pulses at the third frequency do not occur, a second output signal is generated comprised of the pulses of the first input signal during the first periodic interval of the input signal and the pulses of the feedback signal during the second periodic interval of the first input signal.

Abstract: A device is provided for printing a verbal composition in a text form transposed by an operator from the language form in which the source material is presented. Language character forms from different written language formats are encoded and maintained in electronic storage. An operator of the device selects a particular language character from a desired language character font in a single or multiple step selection process to appear at sequential locations of the text during composition of the text. The material to be transposed may be originally presented orally or visually, and is translated or transposed into a different language, or, in the case of some languages, particularly oriental languages, the text may be composed of different language character forms of the same spoken language. For language character forms that utilize a great multiplicity of characters, as opposed to language forms utilizing a relatively few alphabetic or pneumonic characters, a second order selection is made.

Abstract: Video input circuits are disclosed for a video hard copy controller of the type that converts and formats video signals into digital signals for application to a hard copy generating device. The video input circuits comprise a video amplifier circuit having input terminals for receiving a composite video signal comprised of a video data component and a synchronization component, control terminals for receiving a gain control signal to control the gain of the amplifier circuit, and output terminals at which an amplified composite video signal is developed. An automatic gain control circuit is coupled in feedback relation between the output and control terminals of the amplifier circuit for generating the gain control signal to control the gain of the video amplifier such that, in said amplified composite video signal, the potential difference between first and second portions of the synchronization component thereof substantially constant.

Abstract: A recording disk cartridge comprises a housing in which at least one recording disk may be mounted for rotation about its axis. The housing has a peripheral side wall about which a ridge is formed, the ridge being defined by a plurality of sections at least some of which are spaced from one another in a direction parallel to the axis of rotation of a disk mounted in the housing. The dimensions and spacings of the ridge sections are such that the contour of the peripheral side wall at the lower surface of the ridge is the substantial complement of the contour of the peripheral side wall at the upper surface of the ridge. The cartridge also comprises a cover including a peripheral side wall having a contour at its upper surface substantially the same as that of the peripheral side wall of the housing at the lower and upper surfaces of the ridge.

Abstract: A video hard copy controller includes first means for receiving serial input video signals from a first source. Second means is coupled to the first means for converting the serial input video signals into a first set of parallel digital signals. Third means is coupled to the second means for receiving the first set of parallel digital signals. The third means includes means for receiving a second set of parallel digital signals from a second source and means responsive to a control signal for selecting between the first and second sets of parallel digital signals for output to a hard copy generating device in order to produce a hard copy fascimile of the images represented by the selected set of parallel digital video signals.

Abstract: System and method for parallel decoding of character data in run length format to produce data in dot matrix form for presentation to a display device. The data for successive runs is stored in registers and processed in parallel to provide address data for memory devices programmed to deliver predetermined output data patterns in response to the address data.

Abstract: An automatic gain control circuit for controlling the gain of a video amplifier of the type adapted to amplify a composite video signal comprised of a video data component and a synchronization component. The circuit comprises first means coupled to the output of the video amplifier for sampling the voltage level of the amplified composite video signal during a first portion (e.g. backporch) of the synchronization component. Second means is coupled to the output of the video amplifier for sampling the voltage level of the amplified composite video signal during a second portion (e.g. tip) of the synchronization component. Third means is coupled to the first and second means for comparing the actual potential difference between the sampled first and second portions with a predetermined reference potential and for generating a gain control signal representative of such comparison.

Abstract: A data processing system includes a disk drive, a disk drive controller, a main memory and a CPU. The main memory has disk command data stored therein in a chain of disk command blocks (DCB's). Each DCB contains a first word pointing to the next DCB in the chain, a second word containing status information and a third word containing command information. A portion of the command word contains a predetermined verification word when the DCB is valid. The CPU includes means for comparing this portion with the predetermined verification word as stored in a constant memory. If the two correspond, the DCB is valid. Each DCB also includes a fourth word pointing to a block of main memory in which header data is stored. Header data defines the address of the recording location of the disk. A fifth word points to a block of main memory in which label data is stored.

Abstract: The stiffness of a second-order damped servo system with position and velocity feedback circuits is increased without affecting the command response, damping factor, or natural frequency of the system by adding an acceleration feedback circuit and maintaining a specified relationship between the effective gain of the acceleration feedback circuit and the effective gain of the servo driver.

Abstract: A servo system including a recording head to sense servo data on a disk track for fine positoning of the head and an external transducer for generating signals representing the coarse position of the head. A micro-processor stores the coarse positon signals which include information as to repeatable error such as wobble of the disk. A compensator maintains information concerning small offsets of the disk due to, for example, temperature variations. During coarse positioning of the head, from one track to a desired track, the stored repeatable error information and stored offset information is used to generate error signals to control movement of a carriage connected to the head, whereby the head follows the repeatable error and offset to arrive coarsely on the desired track.

Abstract: In a disc drive which does not have a head position sensor but does have a velocity detector and off-track error detection means for sensing the distance and direction of the displacement of the head from the nearest track center, and in which the direction signal from the error detector is of one polarity for odd numbered tracks and of the opposite polarity for even numbered tracks, a system is provided for capturing a track on a blind seek which involves detecting deceleration of the head to below capture velocity, allowing the head to drift past the next track center while sensing whether that track is odd or even, and then initiating a capture of the next following track on the basis of whether the detected track is odd or even and the direction of seek.

Abstract: Video data detect circuits are provided for a video hard copy controller of the type that converts and formats a video signal into a digital signal for application to a hard copy generating device. The video signal includes a video data component and a synchronization component including horizontal synchronization (HS) periods. The video hard copy controller includes means for generating sample clock pulses at a frequency proportional to the HS periods. The video data detect circuits comprise first means for generating a predetermined video threshold reference signal; second means coupled to the first means and responsive to the video signal and to the predetermined reference signal for generating a binary signal at one state for so long as the voltage level of the video signal exceeds that of the predetermined reference signal and at another state for so long as the voltage level of the video signal is less than that of the predetermined reference signal.

Abstract: A higher order servo system including a phase transducer which produces two triangular waveforms, phase displaced 90.degree. in relation to each other, representing the positions of a movable member, and a commutating circuit, responsive to the triangular waveforms, for generating a sawtooth waveform and a velocity signal which is linear and continuous over the whole range of movement of the member. A counter and converter, responsive to pulses also generated by the commutating circuit, generates a staircase waveform, representing predetermined positions of the member, which is added to the sawtooth waveform to produce a positional error signal which is linear and continuous over the whole range of movement of the member. Optimal velocity and acceleration signals are derived from these two linear and continuous signals to drive the member to a desired position over the shortest path, in the minimal amount of time, and with no oscillatory motion at the desired position.

Abstract: A disc drive memory device is described utilizing a continuously rotating drive shaft and a roller which rides thereon to effect translational motion of a carriage to move a read/write head between address locations on a magnetic recording surface of a data storage disc.

Abstract: A transducer coupled to a motor shaft provides both position and velocity information for use in a closed loop control system. The transducer includes a disk with deposited metallic parallel conductors each conductor carrying current in a direction opposite to the adjacent conductor. Relative movement of one disk with respect to another produces a position signal in a manner well known in the art. However, multiple windings are used to provide multiple position signals displaced in space phase which are then processed by differentiation and commutation to provide a velocity signal used as a control voltage in the control loop. A reference signal is also derived by commutation from the position signal.