Nanochip, Inc.

Other

Daniel F Cribbs

Thomas F Rust

Robert N Stark

Thomas L Noggle

John W Hassler, Jr

Michael L Ellenberger

A data storage device comprises a media including a memory layer within which are formable domains associated with information, and a conductive layer disposed over the memory layer, the conductive layer having anisotropically increased electrical conductivity in a thickness direction. A conductive tip contactable with the conductive layer is adapted to form domains within the memory layer and one of the conductive tip and the media is movable to access the memory layer.

Memory having a layer with electrical conductivity anisotropy

Methods in accordance with the present invention can be applied, in an embodiment, to a media comprising a phase change material to alter a resolved portion of the phase change material to have a resistance different from a resistance of the bulk material. A tip having a substantially larger radius of curvature than the resolved portion can be employed by applying such methods. A substantially anisotropic columnar material can focus a current applied between the tip and the media so that the portion is narrower in width than the radius of curvature. Such highly resolved portions form bits in the media. Other objects, aspects and advantages of the invention can be obtained from reviewing the figures, specification and claims. This description is not intended to be a complete description of, or limit the scope of, the invention.

Methods for writing and reading highly resolved domains for high density data storage

Methods for erasing bit cells in a high density data storage device

A method for defining and writing parallel and concentric magnetic signal tracks to a spinning disk surface of a magnetic data storage disk drive system using the components of the Head Disk Assembly (HDA) implemented by an appropriately programmed digital signal central processing unit (CPU) or micro code in an integrated circuit (IC) and a digital signal random access memory RAM is described wherein an initial magnetic signal track is written under least (minimum) energy equilibrium conditions with undulating boundaries and a meandering center line relative to axes of the spinning disk surface for one revolution of the surface. Then servoing to an edge of the just written track, a digitized position signal table is created in memory for storing digital position signals representing the amplitude of the signals read from n sampling points per disk revolution over a number of disk revolutions, where n is determined with reference to `Nyquist criteria`. A comparison/demand signal is derived by the CPU for input to the serve controller for each sampling point by first obtaining a target position signal comprising an average of the digitized position signals stored in the memory table and the just read digitized signal for that sampling point and by then comparing that target position signal to the just read digitizing position signals. The resulting current command signal energizing the actuator is normalized, and variation therein thereafter clamped in steps to bring the slider head to a quiet, least energy equilibrium or coast status relative to the spinning disk surface. A second memory table is generated and stores coast digital position signals for the n sampling points for a plurality of coast or least energy disk revolutions. Servo position then is initiated using averaged values in the second memory table such that any position error signal command to the actuator is a response to random noise or forces. Then preserving the least energy equilibrium state to the extent possible, a subsequent track of servo burst pattern is written onto and around the disk and the procedure repeated referencing the edge of the newly written track. A fiducial track concentric with the axes of the spinning disk is defined by each two iterations of the procedure after writing of the initial track. In this manner track densities in excess of 10,000 tracks per inch (track pitches&lt;100 .mu.in.) can be reliably achieved.

Bootstrap method for writing servo tracks on a disk drive

An embodiment of the present invention is a disk drive comprising a rotating disk with a recording surface, a transducer in communication with the surface and swept radially over the surface by a servo-actuator, a variable gain read amplifier connected to the transducer, an analog-to-digital converter (ADC) attached to the variable gain amplifier, an erase frequency oscillator coupled to the transducer for erasing of the disk surface, a memory for storing digital outputs appearing at the ADC, and a controller for signaling the servo-actuator to move to such radial positions that result in transducer read amplitudes that are a percentage of previous read amplitudes represented in the digital memory. Bit-synchronism between tracks is maintained by writing an initial clock track with closure and then writing a next clock track including a regular sequence of clock bursts a half-track space offset such that the initial clock track can be read in between writing clock bursts and the read signal is used to frequency-lock an oscillator which is used as a reference for the writing of clock bursts of the next track. A checkerboard pattern of clock bursts is thus created. All subsequent tracks are built incrementally by stepping off a half of a track from the last track written, which comprises clock bursts, and writing a next new sequence of clock bursts that interlace with the previous track's clock bursts.

Growing community of inventors

Los Gatos, CA, United States of America

Daniel F Cribbs