Imation Corporation

Minnesota Mining and Manufacturing Company

Daniel P Stubbs

Robert S Jackson

David M Perry

Mark P Lubratt

Andrew John Ouderkirk

Douglas Scott Dunn

Yung Yip

Robert C Martin

Gunter A Kohler

Stephen W Farnsworth

John J Simbal

Jeffrey Bruce Hill

Lewis S Damer

Richard W Duerst

Larold L Olson

Arne Bengt Boberg

C Thomas Jennings

Leslie M Milner

Brian K Parliament

James K Knudsen

Jeffrey A Morgan

Luiz S Pires

Israel Tzur

A secure computing environment in which a computer automatically operates in a full-access data storage mode when it detects the presence of a secure removable storage device. In full-access mode all data written to removable storage device is encrypted with a cryptographic key and the user is given access to sensitive if authorized. Otherwise, the computer operates in a restricted-access mode in which the user is unable to write to the removable storage device and is unable to access sensitive data. The invention detects security information on the data storage device and generates a cryptographic key from the security information. The security information can be a function of the unique format characteristics of the underlying storage medium, a unique identifier retrieved from an electronic circuit embedded within the removable storage device or a serial number etched on the storage device during manufacturing. In addition, drive-specific information and even user-specific information can also be used to generate the cryptographic key, thereby creating a highly secure computing environment. When the computer operates in a full-access mode, all data written to the storage device is encrypted and the user is able access to sensitive data within the organization. When security information is not present on the removable storage device the computer automatically operates in a restricted-access mode in which the user does not have access to sensitive data and data cannot be written to the removable storage device.

Computing environment having secure storage device

In general, the invention provides two-sided magnetic data storage tape comprising azimuthal magnetic transition layouts that can substantially reduce demagnetization of recorded magnetic transitions on the surfaces of the tape. The invention specifically balances the goal of simplified media manufacture with the goal of reducing or avoiding media degradation when the tape is spooled. The two-sided magnetic data storage tape defines a substantially similar easy axis of magnetic anisotropy on a first and a second side of the tape, which can simplify media manufacture. Recorded magnetic transitions on the opposing sides of the tape define azimuths that are substantially different, which can help avoid media degradation when the tape is spooled.

Azimuthal transition layout for two-sided data storage tape

Methods and systems for laser etching of optical servo patterns on magnetic data storage media using two or more beams of laser energy produced from a single source of laser energy to produce a servo pattern on the magnetic data storage media. By using two or more etching beams, the time required to produce a servo pattern on the magnetic data storage media can be significantly reduced. Alternatively, each servo track in the servo pattern can be written more than once. The servo patterns thus formed can be read optically or they may be read magnetically using magnetic overwriting (if the servo pattern is formed in a magnetic coating on the media). In either case, the servo patterns are either permanently formed in the media when read optically, or they can be recreated after bulk erasing if they are provided using magnetic overwriting. In yet another alternative, the servo patterns may be read both magnetically and optically, with the magnetic and optical reading occurring simultaneously or sequentially.

Multibeam laser servowriting of magnetic data storage media

A time-based optical servo system includes at least one optical indicator mark located on at least one servo track of a data storage medium. Alternatively, a pattern of optical indicators is repeatedly recorded in the at least one servo track. A servo read head assembly coupled to a transducing head assembly includes two elongate and non-parallel detection devices having a known relative geometry. The detection devices are adapted to detect the optical indicator marks and determine the time period required for each optical indicator mark to pass between the detection devices. This time period is used to calculate the location of the transducing head assembly relative to the storage medium in a translating direction and produce a position error signal (PES) based thereon.

Time-based optical servo system and method

In one embodiment, the invention is directed toward a magneto-optic read head formed to suppress magnetic exchange coupling at regular intervals along a lateral direction of the read head. For example, in the region of the magneto-optic read head where light is reflected, i.e., the optical scanning region, the read head may be formed with a series of ferromagnetic exchange breaks that reduce lateral permeability of magnetic fields, and hence reduce lateral flux through the read head. In this manner, the effective resolution of the read head can be increased, thereby facilitating readout of data stored on narrower data tracks.

Narrow track resolution magneto-optic read head

Optical servo systems and magnetic data storage tape for use with magnetic data storage drives. The servo system utilizes a head mechanism that includes an optical head and a magnetic head. The optical head is adapted to detect a series of optical indicator marks located on a servo track on the tape. The magnetic head is adapted to detect one or a series of magnetic reference indicator marks located on a corresponding data track. The magnetic reference indicator marks are, in one embodiment, spaced periodically along the length of the tape. The magnetic reference indicator marks allow recalibration of the optical servo system by permitting the determination of any dimensional offset between the optical head and the magnetic head attributable to manufacturing tolerances or environmental factors. In one embodiment, a separate temperature sensor may be used to determine thermal changes in and around the head mechanism. Based on the temperature change measured, a special calibration algorithm may be invoked to recalibrate the distance between the optical head and the magnetic head.

Optical servo system for use with magnetic data storage tape having magnetic reference indicators

The present invention provides methods and apparatus for stabilizing data storage media during laser servowriting of optical servo tracks on the media. The apparatus includes a spindle for rotating the media during servowriting, a fixed media platform, and a media support for stabilizing the vertical position of the media during servowriting. The media support may include channels to reduce or control the formation of an air bearing in the area of servowriting to stabilize the vertical positioning of the media. The media support may also include a vacuum slot for drawing a vacuum through the channels.

Media stabilization for laser servowriting

A system for prolonging the useful life of a mask while ablating a pattern into a workpiece. The system includes a workpiece, a debris-blocking layer thereon, a laser directed toward the workpiece, and a mask provided between the laser and debris-blocking layer. The workpiece may be a data storage disk comprising a substrate and a magnetic coating thereon. The laser may be an ultraviolet laser and the debris-blocking layer should be transparent to the light emitted by the laser. The pattern may include concentric or spiral optical servo tracks in the magnetic coating. The debris-blocking layer minimizes degradation of the mask, thereby minimizing the need to clean the mask and prolonging the useful life of the mask.

System for ablative imaging by proximity lithography

The present invention includes a method of creating a shaped image in a workpiece using a high energy source, with the method comprising positioning a layer proximate the workpiece such that the layer prevents debris from the workpiece from dispersing, and directing radiation from the high energy source through the layer to the workpiece, the layer substantially transparent to radiation emitted by the high energy source such that the high energy source is capable of forming the shaped image.

Ablative imaging by proximity lithography

The present invention provides a magnetic recording medium that includes a polymeric flexible substrate and a magnetic layer coating thereon, with a binderless carbon rich layer adhered to the magnetic layer. The present invention also provides a process for the plasma deposition of the carbon rich coating onto a magnetic medium comprising the steps of:

Growing community of inventors

Marine on St. Croix, MN, United States of America

Daniel P Stubbs