Abstract: For a disk drive servo system using position and position-quadrature signals (P, Q), a method for automatically effecting "Absolute Track Registration" and compensating for "offsets" by using the peak position of one of signals (P or Q) to find "true" position (true offset) for the other (Q or P) wherein the R/W actuator is brought to rest at a reference position and sample-offset signal generated; while the corresponding magnitude of related positioning signals are detected--this being repeated until the peak values of said positioning signals is located whereupon the corresponding position-offset is derived as "true offset"--the actuator then being repositioned by this "true offset" value; and repeating this for a given number of track sites across the disk.

Abstract: Disclosed are air seals adapted to be so engaged in a receiving card rack slot as to thrust out against the opposed slot bases and thus establish "base-engaging" retention forces, this effected in some embodiments by forming a base-engaging flexure strip along each tongue of the seal to that, despite dimensional and other variations, each flexure strip will be thrust-away somewhat from its slot-forming channel, when the seal is firmly seated in a slot.

Abstract: Disclosed are reciprocating carriages carried on roll bearings engaged on guide rails, where some of the bearings are made flexible to be compliantly engaged against a rail surface.

Abstract: A magnetic coating composition is disclosed of the type having magnetic particles dispersed in a resin binder. The improvement comprises the use of a solvent system including a dibasic ester wherein the solvent system has an initial Hansen three-dimensional solubility parameter range of approximately 10.5 to 11.0 and a Hansen three-dimensional solubility parameter range of approximately 9.3 to 10.0 after approximately 99% of the solvent has been evaporated from the binder.

Abstract: Improved transducing techniques and arrangements; the embodiments particularly adapted for co-action with disk drive apparatus for handling flexible disk packs, and including a partitioning shield, flexure-bar mounted transducer head under the shield, along with disk-cleaner/stabilizer means--especially where these are arrayed in the form of a double-opposed transducer assembly adapted to be so manipulated into the pack as to double-partition the pack away from a selected disk on which opposed dual-transducing operations may be carried out.Such arrangements eliminate the need for separate pressure-pads, incorporating them on opposed-heads adapted to transduce on both sides of a record mounted on the ends of respective pivotable flexure-bars. Such cleaner/stabilizers can be opposed, engaged an intermediate record, squeezingly.

Abstract: Described is a technique and associated fixture for lapping magnetic recording heads in a group such that each head is mounted on a "free floating" part in the fixture, being biased for lapping only by the weight of this part and being individually removable during lapping mode; and also characterized by capability for pivoting the fixture to change the lap-angle of all such heads in common to a new constant prescribed angle, the parts also being selectibly kept non-rotatable in the fixture.

Abstract: Improved spacer means for flexible magnetic disk pack storage systems are illustrated in the embodiments, each preferably comprising a set of fingers arrayed on each disk.

Abstract: An improved linear actuator for reciprocating a read/write head mechanism relative to magnetic disk storage system is disclosed, including a second, supplemental solenoid coil and associated magnet means in addition to the usual arrangement, and by way of improving linearity and efficiency.

Abstract: Disclosed is a method and apparatus whereby each time a tape is wound upon a prescribed reel, the winding pattern may be assumed to leave the array of tape edges in a unique "edge profile" represented by the position of each winding edge as viewed from one side of the reel along a radial direction--this "profile" being interpreted as a "winding signature"; the signature may be detected photo-electrically and recorded in a convenient encoded fashion for possible use in uniquely identifying and documenting each unspooling/rewind sequence to thereby monitor tape use.

Abstract: Improved disk pack media for data storage is illustrated as comprising a pack of flexible magnetic recording disks which may be partitioned "end-wise".In one embodiment the disks are perforated for partitioning and also stacked in a different respective rotational orientation to facilitate end-wise partitioning. The disks are hole-encoded and either cut in different hole patterns, or else cut in a common hole pattern and stacked to dispose each in a unique rotational "misregistration" relative to all others--the result being to generate sets of "partition bores" permitting associated automatic apparatus to selectively partition the pack and expose any desired disk-side for operation thereon.In another embodiment the disks are stacked between apertured spacers about a hollow spindle, the spacers and disks being partition-apertured and stacked to generate a set of partition bores.

Abstract: Described is a novel "bevel tool" and associated technique for holding prescribed magnetic head workpieces and placing them in prescribed constant angular relation with a rotary lapping means; this tool preferably including a workpiece-receiving pocket adapted to be spread apart and to resiliently grip the work, with one or more guide-faces surrounding this pocket and adapted to indicate a prescribed orientation of the work against a prescribed "lapping plane".

Abstract: Magnetic recording media having a coating containing harsh pigment like CrO.sub.2 particles and adapted for frequent contact with a head, with good durability, abrasivity, etc., accommodated by using a lubricant system including a fluoro-silicone oil and a compatible fatty-acid-ester like butoxy ethyl stearate.

Abstract: Low performance ferromagnetic oxides are taught to be convertible into high performance ferromagnetic oxides with vastly improved coercivity by suspending ferromagnetic oxide particles in aqueous media, forming a layer of the first metal on the surfaces of the particles, forming a layer of second metal on the surfaces of the first metal and lastly, forming a layer of third metal on the surfaces of the second metal. The first and third metals can be the same in preferably transition metals such as cobalt. The second metal must be different than the first and third metals such as, for example, iron.

Abstract: Described are Delta-shaped magnetic recording "sliders", some being provided with a "back-bar" and associate "purge channel", the air bearing surface area of the sliders increasing gradually from a minimum at its nose to a maximum at its trailing edge.

Abstract: Described is a novel technique and associated arrangement for determining the noise-free value of a system parameter (e.g., head position in a disk drive) which is time variable and (usually) has a noise component as detected. The technique involves processing the (as detected) noise-including value and passing it, plus a "Time-derivative version" thereof, through "Second Order/Summing" filter means.For instance, the technique is described as particularly useful with the "track-following servo" (part of the transducer positioning means) in a high density disk file (where track density is higher than usual) to secure superior head-displacement error values which are more noise-free. Thus, (see FIG. 4), a pair of first values V.sub.a, V.sub.b are secured by detecting motor current sense voltage V.sub.i, integrating it with respect to time and passing the result through a pair of novel "second order filter" means--one band-pass (F.sub.1), the other low-pass (F.sub.2); while also securing a third value V.sub.

Abstract: A method and associated fixture for magnetically attracting and holding back-bar to respective magnetic core-leg portions of a typical magnetic slider assembly. A plurality of embodiments constructed in accordance with different fabrication techniques are described.

Abstract: Described is a fixture for glass-bonding a digital magnetic recording slider workpiece (the component parts thereof), while holding them carefully aligned. In one preferred embodiment this fixture includes a slot for receiving a number of such work pieces in pre-assembled form registering and aligning them together and providing retainer means individually for each work piece adapted to resiliently and selectively engage each work piece and hold it positively in careful precise alignment while glass bonding and related operations carried out on the array of multiple work pieces so-aligned and retained.

Abstract: An improved linear actuator for reciprocating a read/write head mechanism relative to magnetic disk storage system is disclosed, including a second, supplemental solenoid coil and associated magnet means in addition to the usual arrangement, and by way of improving linearity and efficiency.

Abstract: Disclosed is equipment for testing a magnetic recording head; comprising a circuit which generates a test signal simulating what the head under test would generate.

Abstract: Improved flexible disk pack magnetic storage systems and associated elements are illustrated as adapted for pneumatic partitioning and indicate, among other features, the use of spacer segments in the gap between adjacent flexible disks these being pre-attached to each disk to isolate the axial pressurized air streams from non-selected gaps and also to provide a reference surface for registration of the disks in the course of compressing the stack together.