Abstract: A large capacity data storing disk includes a volume table of contents (VTOC) which identifies allocated ones of data storage tracks and identification of the data contents therein, indications of unallocated data storage track and an indication of which of the data storage tracks on the large capacity disk surface are unformatted. The indications may also include indications of unallocated "erased" tracks that do not contain data residuals from previous recordings. Those unallocated tracks having such erased condition in a count key data record format (CKD) require a home address record on each of the formatted tracks. The home address record may include indications of rotational position of defects to be skipped over during the recording and readback operations. A specific embodiment of the invention using a magnetooptic record medium is described.

Abstract: There is disclosed a method for optically recording data in data areas of a disk-like recording medium in which servo signal areas are formed along the track in alternation with data areas. Parity codes for error correction are generated and affixed in at least one direction, that is, in the column or row direction, of a two-dimensionally arrayed data block, and the two-dimensionally arrayed data affixed with the parity codes are supplied sequentially to an optical pickup along any one of the column and row directions so as to be recorded in respective ones of said data areas.

Abstract: A data separator system has a PLL circuit for out-putting data pulses and clock pulses on the basis of the read data from a magnetic recording medium. The system also includes an external synchronization detection circuit which detects the synchronization data (predetermined zero pattern data) recorded in the synchronization area of the magnetic recording medium, on the basis of the read data. When detecting the synchronization data, the synchronization detection circuit enables the PLL circuit to oscillate in synchronism with the read data. The data pulses and clock pulses output from the PLL circuit are also supplied to an internal synchronization detection circuit. On the basis of the data pulses and the clock pulses, the internal synchronization detection circuit detects the synchronization data, and upon detection thereof, a floppy disk controller performs the data readout operation.

Abstract: Methods and apparatus are disclosed which utilize isotropic/perpendicular medium for performing high density digital magnetic recording. According to the preferred embodiment of the invention, the l's of a binary code are deeply imprinted on the medium by switching off the current in the winding of a magnetic ring head. The l's so imprinted on the medium are each represented by a copy of a part of the fringing field of the ring head. Each imprinted field has the appearance of a "horseshoe" pattern of magnetization. During readback these imprinted patterns correlate extremely well with the sensitivity function (the fringing field) of the ring head/readback transducer. The invention utilizes this inherently present correlation, together with a combination of longitudinal and vertical recording techniques, to provide methods and apparatus well suited to locate signals buried in noise and yield improved overall readback performance in a high density environment.

Abstract: A multichannel communications recorder or logger. The recorder is formed from modular elements which may be configured into a large number of selectable configurations. In each configuration one or more record decks is controlled by a control module which includes a system control microprocessor and a CRT control microprocessor. Control is provided by a user selecting to implement functions defined in accordance with a particular page displayed. Access to various pages is controlled by various levels of passwords with the highest level being used by a service person and lower levels being provided to users of the system. Because of the need to provide physical security for recorded tapes, each tape deck is provided with a door secured by an electro-mechanical lock. Because of the need to maintain continuous monitoring in many applications, the system is provided with the capability to be configured in configurations providing back-up for selected channels.

Abstract: An information recording and reproducing apparatus for recording and reproducing information on and from a disk type information recording medium, wherein the information recording medium is used in which normal sectors (s1, Sn) each having an address formatted on an address area 12 in a sector ID field 9 and an alternative sector R1 having an address not yet recorded thereon are included on a same track. When a defective sector S3 is detected, first, the address of the defective sector is disabled to be reproduced by recording a delete signal 109 on the address area 12 of the defective sector S3, and at the same time, the address of the defective sector is recorded on an address area 13 in the unused alternative sector R1 located on the same track as the defective sector S3, and then, the data to be recorded on the defective sector is recorded within the alternative sector R1.

Abstract: A digital recording and reproducing system for ME tape uses a class 4 partial-response encoder in the recording apparatus and a corresponding decoder in the reproducing apparatus. A high signal-to-noise ratio is achieved without the need for a phase equalizer.

Abstract: The record mode setting apparatus comprises a VPS setting switch (41), a VPS decoder (3), a code latch circuit (7), a VPS control circuit (26) and a code memory (27). When the VPS setting switch (41) is turned on while a recording means (16) is ready for recording, the VPS decoder (3) detects a VPS code out of a video signal and the VPS code is stored in the code memory (27). Thereafter, the VPS code detected by the VPS decoder (3) is applied to the code latch circuit (7). The VPS control circuit (26) compares the VPS code of the code latch circuit (7) with the VPS code stored in the code memory (27) and stops the recording means (16) when both do not coincide with each other.

Abstract: A thermomagnetic recording method is disclosed using a thermomagnetic recording medium where first, second and third magnetic thin films each formed of rare-earth and transition metals are sequentially superposed to form layers in a magnetically coupled manner. The recording is carried out by heating the thermomagnetic recording medium under a predetermined magnetic field perpendicular to the film plane thereof while selectively modulating, in accordance with data to be recorded, a first heating state at a first temperature T1 substantially above the Curie point Tc1 of the first magnetic thin film and adequate to hold the sublattice magnetization of the transition metal of the second magnetic thin film in a predetermined direction, and a second heating state at a second temperature T2 substantially above the Curie point Tc1 and adequate to invert the sublattice magnetization of the transition metal of the second magnetic thin film to the reverse of the predetermined direction.

Abstract: A system for storing and retrieving encoded data on an optical recording medium using pit edge detection is disclosed. The pit extension characteristics of a given medium are determined by first using laser beam test write pulses to form one or more pits on the medium and then detecting the time durational difference between the pulse width of the test write pulses and the duration of the leading edge transitions to trailing edge transitions of the corresponding pits formed on said medium. This difference value may be stored in a certification sector of the medium. Subsequent write pulses are modified in duration in an amount equal to this detected durational difference. For forming a pit that is longer than a predetermined minimum length, the corresponding write pulse is made non-continuous in order to minimize cumulative pit extension.

Abstract: Data is received at a variable input rate and recorded on a longitudinal medium in the form of fixed length data blocks with variable length spacing between the blocks, utilizing a transducer mounted on a rotating scanner drum. The input data rate may change between various recording/playback operations by a ratio of 1:100 or more, but during a particular operation it remains constant. The data blocks played back from the medium are sequentially stored in a memory at the internal data transfer clock rate, which is also utilized to control the scanner rotation. The data is read from the memory at a constant rate which is adjusted for each particular operation. A memory status control signal is m provided indicating a predetermined level of fullness obtained by the memory. That control signal is compared in time to a control signal indicating occurrence of the beginning of a next data block.

Abstract: A method and system for recording an asynchronous, biphase encoded signal (such as a MIL-STD-1553B signal), having a first data rate, on a video tape recorder, which may be a consumer video tape recorder, and for recovering the encoded recorded data for subsequent transmission in its original format. The asynchronous biphase enceded signal is synchronized with a clock signal having frequency equal to twice the first data rate. The synchronized signal is then stored temporarily in a buffer memory as if it were an NRZ bit stream having bit rate equal to twice the first data rate. The data is read out of memory and combined with television-type synchronization pulses to produce a television-type signal for recording on the VTR. In the play back mode, the recorded VTR signal is separated into its data component (which consists of bursts of data that occupied the active video areas) and sync component. The invention eliminates the need to use specially designed recorders for asynchronous biphase encoded signals.

Abstract: A reproducing apparatus for reproducing blocks from a recording medium on which a plurality of signal blocks are recorded on plural recording tracks, uses a rotary head which is rotated at a speed equal to at least twice the normal speed. Error detection of a reproduced signal is performed for each signal block, and a detection signal and a reproduced signal of the corresponding signal block are written into a memory. If the detection signal indicates that no error is detected, the reproduced signal from the corresponding signal block is prevented from being written again into the memory. A reproduced track address signal and a reference track address signal are compared, and in accordance with the comparison result, translation of the recording medium is controlled.

Abstract: A digital information signal recording apparatus has a first mode in which a digital information signal of one channel is recorded on a recording medium at a given bit rate and a second mode in which digital information signals of n channels (n: an integer which is at least 2) are simultaneously recorded on the recording medium at a bit rate which is 1/n of the given bit rate.

Abstract: A clock regeneration circuit for use in data reproducing apparatus which reproduces and demodulates digital data that has been recorded on a magnetic medium in accordance with different types of modulation having different recording densities, such as biphase-mark modulation and 8-10 modulation, respectively. The clock regeneration circuit includes a phase locked loop for regenerating a clock signal from the clock component included in the reproduced data and comprises a switchable voltage controlled oscillator for selecting the frequency of a reference signal generated thereby in correspondence with the type of modulation which had been used for recording. Also included in the clock regeneration circuit is a phase comparator and a switchable low pass filter for supplying the output of the phase comparator to the voltage controlled oscillator, the time constant of the filter being selected in correspondence with the type of modulation that was used for recording.

Abstract: A shock load detection device mounted on a disk drive housing of a computer disk drive unit to issue a write-fault signal should the disk drive unit have a mechanical shock imposed thereon. The detection device includes three piezo-electric crystals mounted orthogonally between a base and a seismic mass. Any shock load along x, y, and z axes through the piezo-electric crystals produces an electrical charge which is amplified, filtered, and compared for issuing a write-fault signal. The write-fault signal is used to stop the writing of read/write heads on a spindle of a head disk assembly before the shock imposed thereon could otherwise move the read/write heads off track causing a data error.

Abstract: In a recording/reproducing apparatus, having an analog-to-digital converter used in a recording mode and a digital-to-analog converter used in a reproducing mode; a digital filter comprises memories for storing first and second multiplication coefficient groups which provide predetermined filter characteristics and are in interpolated relation to each other; and, in the recording mode for first-and second-channel signals, the first and second multiplication coefficient groups are used for the first-and second-channel signals, respectively, and, in the reproducing mode, the second-and first-multiplication coefficient groups are used for the first-and second-channel signals, respectively. In recording and reproducing modes for a single-channel signal, the first and second multiplication coefficient groups are alternately used for successive samplings.

Abstract: Herein disclosed is a method for storing data in a rotary type recording medium rotating in a predetermined direction in which the read of the information from one track to an adjacent track is conducted substantially continously when the head is moved in the first direction but discontinuously when the head is moved in a second direction reversed from the first one. The data is stored in at least one storage area on the recording medium such that data blocks are written in the order of tracks in the second direction, such that the newest data block leads in each track, and such that the data blocks in the storage area are read in the order from the newest one when the head is moved in the first direction.

Abstract: Signal heads are displaced relative to a recording surface on a stationary recording medium having a separate surface on which visual data is recorded and displayed. Differential drive mechanism and adjustable resistor means effects signal head displacement along a predetermined path on the recording surface at a constant speed.

Abstract: An erasing method is used for erasing a video signal written on a track of a rotary magnetic recording medium such as a floppy disk in which the track to be erased is scanned by a magnetic head used for recording. An erasing current having a gradually decreasing amplitude level is applied to the magnetic head. The initial amplitude level of the erasing current is greater than the optimum recording current level for the magnetic head.