Abstract: The specification discloses a method and apparatus for servo-positioning moveable transducer heads and the like by means of time-based servo system utilizing a particular type of servo pattern or format recorded on a data storage member, e.g., magnetic tape or disk, and having first and second sets of servo lines that extend angularly across the recording media from opposite sides thereof convergently toward one another. The individual lines in each such set of recorded servo information extend alongside one another without intersecting, and in a preferred embodiment the two sets of servo lines intersect along a medial portion of the recording media, to define a uniform series of angles disposed adjacent one another along the recording member, a preferred such pattern having a chevron-like appearance. The overall servo pattern formed by the two sets of servo lines preferably extends across substantially the entire usable surface of the recording media to provide continuous servo-positioning.

Abstract: A positioning apparatus used for information-storage devices provides stoppage of a motor-driven transducer head-positioning lead screw follower as the follower approaches the motor-driven end of the lead screw. An element is provided on the follower which contacts a stop carried by the lead screw when the follower arrives at a position spaced from the motor by a predetermined distance, to thereby prevent the follower from moving any closer to the motor than such predetermined distance.

Abstract: The specification discloses means for correcting timing variations present in a data stream emanating from a data storage device such as a magnetic tape drive or the like before the data stream is applied to the data separator or other such input device of a computer. This is accomplished by remodulating the time-varying bits in the data stream in a manner which reduces or eliminates the undesired timing variations. Basically, the system utilizes frequency-modulation techniques to in effect remodulate the raw data stream. The application discloses, as one preferred embodiment, a pulse-width modulator which receives the error signal output of a phase-locked loop network, the input of the pulse-width modulator being coupled to the incoming raw data stream.

Abstract: A positioner mechanism for moving read-write heads in formation storage devices from one track to another across a record member, including a positioning arm which extends between the transducer and its mounting structure, disposed at one end of the arm, and a motion-imparting means (e.g., a lead screw drive) at the other end, with a pivotal arm-mounting means therebetween, whereby the motion of the arm at its end extremities is arcuate, and a calibrated lost-motion or compound-motion means connecting the arm to the transducer and/or the motion-imparting means, such that the arm moves the transducer in uniform increments along a rectilinear path notwithstanding the curvilinear motion of the arm itself.

Abstract: A magnetic core structure for a "read-write" transducer head of the type known as a "wide-write, narrow-read" head, having at least one magnetic gap, wherein the magnetic pole structure performing one of the transducing functions (e.g. the "write" function) is in effect wider than that performing the other (e.g. the "read") function. At least one such magnetic pole has a laminar structure comprising at least one medial layer or strata and at least one flanking layer or strata which is disposed adjacent to and overlying at least portions of the medial strata, to thereby define an included area of overlap therebetween. The thickness of the medial strata, measured along the length of the gap, is less than that of the magnetic core structure on the opposing side of the gap.

Abstract: A magnetic core structure for a transducer head of the type used in digital data storage devices is wider on one side of the magnetic gap (e.g., the write side) than it on the other side of the gap (e.g., the read side), to provide "wide write-arrow read" recording and reproducing capabilities. Magnetic flux return during recording (writing) operations is accomplished through the comparatively narrow read core plus additional magnetic closure elements which are disposed alongside, and which magnetically shunt, the read core, such that the overall core structure has basically the same width on each side of the magnetic gap. Improved transducing performance is provided by using additional thickness for such magnetic shunts and recessing the end extremity of the latter adjacent the gap at the face of the head, where the head accesses the magnetic recording media, such that the overall magnetic reluctance of the magnetic returns (i.e., shunts) is lowered but the effective gap width of the head is not changed.

Abstract: A magnetic core structure for a "read-write" transducer head of the type known as a "wide-write, narrow-read" head, having at least one magnetic gap, wherein the magnetic pole structure performing one of the transducing functions (e.g. the "write"function) is in effect wider than that performing the other (e.g. the "read") function. At least one such magnetic pole has a laminar structure comprising at least one medial layer or strata and at least one flanking layer or strata which is disposed adjacent to and overlying at least portions of the medial strata, to thereby define an included area of overlap therebetween. The thickness of the medial strata, measured along the length of the gap, is less than that of the magnetic core structure on the opposing side of the gap.

Abstract: A cartridge drive adapted for endwise loading of tape cartridges has a retractable friction roll to open the tape access door as the cartridge is loaded into the drive. A pivoted cartridge carriage swings the loaded cartridge across the loading path of travel to an operative position in engagement with the drive motor and magnetic head of the drive. In preferred forms, the drive is dimensioned to fit within the "foot print" of a standard 51/4" floppy disk drive.

Abstract: The specification discloses a system and method for storing digital information on a magnetic tape wherein redundant information is generated and also stored so that subsequently unreadable portions of the tape can be regenerated based on the readable portions. The tape is formatted to include a plurality of sequentially arranged blocks, each including a plurality of generally identical data sectors and error-correction sectors. The placement of the data sectors and the associated error-correction sectors within a common block facilitates, and increases the speed of, tape writes and reads. Preferably, a Reed-Solomon code is utilized to generate the redundant information in the error-correction sectors as a preferred balance between recoverability, tape overhead, and speed of encoding.

Abstract: A miniaturized tape cartridge drive for data processors in accordance with the invention has as peripherally-enclosing main frame providing an access opening for insertion to a tape cartridge and structurally mounting flat, pancake-type drive motors for tape transport and head-positioning translation laterally with respect to the tape, for accessing any of a plurality of adjacent recording tracks on the tape, such motors being disposed in tandem with respect to the cartridge-admitting opening and having their output shafts pointing in opposite directions. The head-positioning motor drives a directly-coupled rotary cam, and a positioning arm extends between the cam and the transducer head to move the head in response to movement of the cam. The positioning arm is pivotally journaled in opposite sides of the main frame upon a transverse pivot axis disposed medially of the arm, such that the arm operates as a fulcrumed lever.

Abstract: Apparatus and method for decoding of transducer head-positioning information which has been recorded on data-storage media, in particular magnetic tape, and for use of the decoded information to position a transducer head, wherein the transducer head reads the recorded information and its output signals are sampled at predetermined times to determine their magnitude and a digital representation of such magnitude is obtained by timing an interval during which a reference source increases at a known rate from a first value to a second value whose difference corresponds to the detected magnitude of the transducer output signals. The timed interval is outputted in the form of a digital count value which is thus representative of the head-positioning information read out from the data storage media, and the digital signal provided by such count value is then used in positioning, or repositioning, the transducer head in a representative manner.

Abstract: A method and apparatus for initializing a data-recording media, particularly tape, by use of the same type of media drive used for data-recording purposes, in which the actual edge of the recordable field on the media is first located by a test read/write process and the media is then transported in a succession of passes across the transducing head, during each of which the head is periodically and selectively energized to write mutually-spaced marker bursts and servo-positioning bursts, with the transducing head being moved open-loop a distance corresponding to a half-track width between each media transport. During the first such pass, the marker bursts and servo-positioning bursts are located on the basis of tape travel distance, and on successive passes burst location is determined by sensing the previously-recorded marker and servo bursts and timing-out a predetermined distance therefrom by use of an internal clock.

Abstract: Analog servo-positioning signals transduced from a recorded member, such as embedded servo signals recorded on a disc memory or the like, which are to be compared to one another in order to derive an error signal indicative of off-track position deviations, are normalized for accurate responsive positioning changes by use of an analog-to-digital converter referenced by both a positive and a negative summation of the two analog signals and supplied with the individual analog signals as inputs, such that the digitalized output comprises a pair of digital signals, the first representative of the quotient of the first analog signal divided by the summation of the two analog signals, and the second representative of the second analog signal divided by the same summation of analog signals.

Abstract: A recording member for digital data, particularly a recording tape, has a plurality of generally parallel, closely-spaced recording tracks which each contain pre-recorded track-identifying and transducer-positioning servo information, as well as defined data-recording areas. The pre-recorded track-identifying information preferably comprises a digitally-encoded individual track address, and the servo information comprises separate bursts used in centering the transducer upon a particular track. Preferably, each such track has a dedicated area at its beginning, end, or both, which contain continuous repetitions of such positioning information, there being no data areas in such dedicated portions. Digital encoding of track addresses utilizes binary-type code format, accomplished by defining a binary "zero" as a recorded burst present at a first number of sampling points, and defining a binary "one" as a burst present at a second number of sampling points of a second duration.

Abstract: A cartridge drive adapted for endwise loading of tape cartridges has a retractable friction roll to open the tape access door as the cartridge is loaded into the drive. A pivoted cartridge carriage swings the loaded cartridge across the loading path of travel to an operative position in engagement with the drive motor and magnetic head of the drive. In preferred forms, the drive is dimensioned to fit within the "foot print" of a standard 51/4" floppy disk drive.