Abstract: The present invention provides a complete digital data storage (DDS) magnetic tape system for utilization with a host unit. The invention comprises a host device interface for interfacing the host unit with the DDS system, a controller/formatter for encoding and decoding data from and to the magnetic tape, an automatic track follower (ATF) for performing automatic track following on the magnetic tape, a driver for driving the magnetic tape, a read/write (R/W) channel for channeling data thereto and therefrom, a read/write (R/W) head drum for transferring data to and from the magnetic tape, and the controller/formatter, the ATF, the driver, the R/W channel, and the R/W head drum all being under software programmable control.

Abstract: An automatic track follower (ATF) system for accurately positioning the read/write head on the tracks of a magnetic tape comprises a pilot signal generator for generating pilot signals from tape pilot marks; a sample-and-hold circuit for sampling the pilot signals from the tracks immediately adjacent a track being read; a comparator for comparing the magnitudes of the pilot signals from adjacent tracks on both sides of the track being read; a correction circuit for centering the read/write head on the track being read; and a processor for digitally controlling the generator, sample-and-hold circuit, comparator, and correction circuit and their functions, the digital control being under programmable control. Three code bit fields are discriminated from the digital data to detect the beginning of the ATF field on the tape to derive the ATF logic, timing, and control functions.

Abstract: In a digital data storage audio tape system having a host device interface unit, a main data buffer manager, a main data buffer, a processor, a data separator, a tape drive unit, and a read/write channel, this invention comprises a formatter providing track construction, encoding and decoding, error correction, and direct memory access of digital data transmitted between the host device unit and the tape drive unit and a frame buffer for buffering digital data for encoding and decoding, and error correction. The formatter is coupled between the main data buffer manager, via a direct memory access channel, and the read/write channel of the tape drive, and further is coupled to the frame buffer. The formatter is coupled to and responsive to instruction control by the processor in conjunction with instruction control of the tape drive unit by the processor.

Abstract: A complete digital data storage magnetic tape system for utilization with a host unit comprising a host device, an interface for interfacing the host unit with the DDS system, a controller for encoding and decoding data to and from the magnetic tape, an automatic track follower for performing automatic track following on the magnetic tape, a driver for driving the magnetic tape, a read/write channel for channeling data thereto and therefrom, a read/write head drum for transferring data to and from the magnetic tape, the controller, the automatic track follower, the driver, the read/write channel, and the read/write head drum all being under software programmable control.

Abstract: The present invention is an input/output controller for providing total data integrity for any single point failure. The I/O controller comprises a processor module having two microprocessors, an associated memory, a direct memory access module ("DMA"), and a processor support module ("PSM"); a device drive interface; and a channel interface. The two microprocessors are operated in lockstep as a dual modular redundant processor system. The processors provide true and complement, respectively, addresses, data and control strobes. The PSM compares the true and complement data to detect errors (i.e., corresponding data bits not being a true-complement pair) and generates parity protected data (and checks parity) on the data bus. The PSM also generates and checks dual railed control strobes and provides synchronization of all control strobes and interrupt signals to enable the tru-complement pair of microprocessors to operate in lockstep.