Abstract: A composite structure for magnetic recording includes a core member of polymeric material to which is bonded at least one silicon disk having a magnetic recording material on its outer surface. The silicon disk surface provides optimal flatness and smoothness characteristics for a magnetic recording substrate, while the polymeric core member provides strength to the structure.

Abstract: Multi-layer magnetic thin film disks comprising a synthetic resin layer on an aluminum-containing substrate and an overlying metallic magnetic layer, are liable to have pin holes in the synthetic resin layer caused by galvanic corrosion of the aluminum in the substrate. The pin holes are passivated by aluminum oxide produced therein by anodically oxidizing the aluminum of the substrate in an electrolytic bath, the electric voltage of which is well below the normal passivation voltage for aluminum.

Abstract: A monolayer magnetic coating is prepared by applying magnetic particles which have an electrostatic charge in an aqueous environment to an active layer on a substrate, the active layer having an electrostatic charge in an aqueous environment opposite to the charge on the magnetic particles so that the particles bond to the active layer.

Abstract: A magnetic recording device employing a thin foil member is fabricated by radially compressing a ring member, securing the periphery of the foil member to the compressed ring, releasing the compression on the ring so that it expands to produce tension in the foil member.A magnetic coating may be applied to the foil member either before or after securing it to the ring member.

Abstract: A circuit provides either the J-K logic function or the Exclusive Or (EOR) logic function depending upon a control signal. The circuit includes a conventional cross-coupled EOR block with two inputs, the logic function being performed by the block depending on the presence or absence of the control signal.

Abstract: Structure for providing a file protect function for a removable cartridge which houses a magnetic recording medium includes a rotary actuator in a sleeve member, the actuator having an outer disk and an inner disk. The actuator may be rotated in the sleeve to either of two positions 180.degree. apart by application of force to the outer disk. The inner disk has an interrupted segment therein, and the rotational position of this interrupted segment controls the enabling or disabling of the circuitry for recording on the magnetic medium.

Abstract: Structure for providing a file protect function for a cartridge which houses a magnetic recording medium includes a sleeve molded integrally with the cartridge. The sleeve has diametrically opposed slots and a rotary file protect actuator disposed in the sleeve has diametrically opposed projections which engage the sleeve slots to hold the actuator in position. The actuator may be rotated 180.degree. by a screwdriver or other tool, and this rotation controls the enabling or disabling of the circuitry for recording on the magnetic medium to provide a file protect function.

Abstract: A magnetic recording device employing one or more thin circular foil members which are secured to a supporting member on at least the outer edges of the foil members. In one embodiment, the foil members have central openings therein, with the central opening in one foil member being larger than the opening in the other foil member. A clamping and spacing member is secured to the foil member having the smaller opening and extends through the larger opening in the other foil member to both provide a means for transmitting rotational force to the structure and to provide for spacing between the structure and an adjacent structure in a recording assembly.In an alternate embodiment, one of the foil members has a central opening while the other does not, and rotational force is transmitted through the foil without the central opening. As additional alternatives, the foils may have central openings of equal sizes and be secured to support members either at their outer edges or at both their inner and outer edges.

Abstract: A method and means are provided to increase the effective data transfer rate between a direct access storage device (DASD) and a central processing unit (CPU) communicating with the DAS device through a channel and a DASD control device.A command issued to the AS subsystem which requires mechanical motion in the DAS device is stored in the subsystem and the subsystem provides a response to the channel indicating that the command has been carried out, without actually carrying out the command. The channel responds by issuing one or more additional commands in the chain to the subsystem which may be carried out without mechanical motion. When a command is issued to the subsystem which again requires mechanical motion of the device, the control device causes the stored command to be executed essentially simultaneously with the newly received command.

Abstract: Direct method for measuring the magnetostriction constant .lambda..sub.s of soft magnetic and isotropic magnetic materials. A thin film sample is cantilevered and clamped at one edge. Under the influence of a magnetic AC field and the magnetostriction effect of the sample material, the free end of the cantilevered sample is deflected and oscillates with twice the frequency of the AC field. The resonance amplitude a.sub.res is measured by using a laser beam impinging upon the oscillating sample and measuring the reflected beam amplitude by means of a position-sensitive photodiode. The AC output signal of the photodiode is proportional to the sample amplitude. The magnetostriction constant .lambda..sub.s is directly proportional to the resonance amplitude a.sub.res multiplied by a constant factor which depends on known geometry and properties of the sample material.

Abstract: A sampled data servo positioning system employs an actuator to move a member between a current and a target position. Incremental position feedback is provided only at sampling times. The system employs a model responsive to a velocity related input signal to produce a continually available model incremental position signal. Phase comparing means indicates phase differences between the model and sampled position signals at the sampling times.The system has two operational configurations in the first of which a source of saturation control signals is connected to the actuator to cause maximum acceleration or deceleration thereof. In this first configuration, the model is forced to track the actuator motion by means of feedforward plus feedback control. The feedforward signal represents actuator performance while the feedback signal is the position signal phase difference.

Abstract: A disk file employs a disk having sectors of track-following servo information interspersed around the disk between data portions. Included in each sector is a SYNC signal which is encoded to indicate the validity or invalidity of the servo information in that sector. The servo information in a sector is used only if the SYNC signal indicates that it is valid.

Abstract: A magnetic dispersion is prepared by adjusting the pH of a mixture containing magnetic particles to a value which results in a positive electrostatic charge on the particles, while a mixture containing colloidal silica particles at the same pH results in negative electrostatic charges on the silica particles. Combining these mixtures causes the silica particles to coat and irreversibly bond to the magnetic particles resulting in better dispersion and less aggregation of the magnetic particles.

Abstract: A method and means are provided to facilitate the exchange of data between a direct access storage device (DASD) and a central processing unit (CPU). The data is stored in fixed length records on the DASD.A pair of sequential commands are issued by the CPU to control access to the DASD data. The first command contains information which defines the boundaries of the DASD storage space which the CPU can access. The second command identifies the operation to be carried out within the permitted space defined in the first command and establishes where within the permitted space the activity is to take place.The use of these two commands reduces the amount of CPU software involvement which is required for data accessing, particularly where the accessing involves the crossing of geometrical boundaries on the DASD.

Abstract: An Optical Character Recognition (OCR) system for printed characters uses information about baseline location to assist in registration, segmentation, recognition and the separation of underscoring. Selected ones of the sensor elements in the OCR scanning array are identified as defining a baseline searching window and the outputs of these selected elements are utilized to detect baseline information for each character or group of characters in a printed line.

Abstract: A thin film magnetic recording medium for deposition on a record carrier includes a ferromagnetic alloy containing iron, cobalt and chromium. The ferromagnetic alloy consists of from 0-55% cobalt, from 8-22% of chromium with the remainder iron. The preferred range of chromium is from 10-18%. The magnetic recording layer is vacuum deposited over an extended portion of a record carrier for storing information which is represented by the spatial distribution of magnetic transitions in the magnetic layer. The iron-cobalt-chromium or iron-chromium composition according to this invention, gives the best magnetic properties consistent with excellent corrosion resistance.

Abstract: Means are provided to prevent the failure of an Initial Program Load (IPL) command in a data processing system because of a "busy" indication from a Direct Access Storage Device (DASD) control device which is executing the command. An IPL operation from a Central Processing Unit (CPU) involves the issuance of a System Reset signal to all channels and control units connected to the CPU, followed a short time later by a READ IPL command to the DASD control device controlling the DAS device which contains the program to be loaded. The present invention enables the system to distinguish between when a control device is busy with a System Reset procedure and when it is busy on other matters, and to permit the queueing of the READ IPL command when the control unit is busy and there is a System Reset operation pending so that the READ IPL command will not be rejected.