Micron Technology Incorporated

Maxtor Corporation

John L Seabury

Bruce A Liikanen

Gerald L Cadloni

Stephen P Van Aken

Larry Joseph Koudele

Guy R Wagner

Robert B Eisenhuth

Don Brunnett

Brian P Rigney

John VanLaanen

Steve McCarthy

Jason Laks

Stephen P VanAken

Bruce A Liikenanen

A system uses multi-level encoding where each symbol of a plurality of symbols represents more than one bit of information in a user data symbol stream for transfer using a multilevel transmission channel. The user data symbols are represented in a digital bitwise form such that each symbol is presented as a plurality of bits and each bit is subject to a different probability of error. An error correction procedure is applied based on the different error probability that is associated with each bit in the plurality. The channel can be configured to support a mosaic tile structure, each tile containing a channel symbol such that a selected tile has a collective error probability that is different from other tiles. Customized coding can be applied to the tile structure to allocate a selected amount of error correction power to the selected tile based on an overall available correction power.

Bitwise operations and apparatus in a multi-level system

Apparatus and methods are disclosed, including a method of programming involving determining an error rate for the memory cells, and programming the memory cells using a charge state level for a charge state that is based at least in part on the determined error rate.

Apparatus and methods of programming memory cells using adjustable charge state level(s)

In one embodiment, an encoder reads a set of data from memory cells to obtain retrieved data influenced by one or more distortion mechanisms as a result of having been stored. A quality metric is generated responsive to the retrieved data that changes in value responsive to differences between the user data and the associated retrieved data. A quality monitor establishes a relationship between a current value of the quality metric and a threshold value and monitors the relationship as being indicative of a degradation of the quality of the retrieved data, and selectively initiates an error response. In another embodiment, a correction value is iterated through a set of values as a quality metric is monitored such that the value of the quality metric which most closely approaches the value of the quality metric immediately subsequent to an initial writing of the data can be selected.

Memory quality monitor based compensation method and apparatus

A memory system for digital data communication with a host device is described to provide data storage capacity. The system can include a controller and a plurality of modules, each module including a nonvolatile memory device wherein the module is configured to perform a management function with respect to the module at least partially based on a parameter. The parameter is provided by the controller and/or the module. The system and modules, in one feature, can support multiple forms of concurrency with respect to data accesses involving the modules.

At least semi-autonomous modules in a memory system and methods

The present invention is directed to a method and apparatus for performing a self-servo write operation in a disk drive. In one embodiment, the disk drive includes a disk surface having a read head and a write head associated therewith. Spiral servo information is written onto the disk surface in a closed-loop fashion through use of a servo track writer. The read head reads the spiral servo information and is used to position the write head, which writes final servo information onto the disk surface. The final servo information may be embedded servo information. The final servo information that has been written onto the disk surface looks substantially identical to a disk surface that has had its final servo patterns written using a servo track writer.

Method and apparatus for performing a self-servo write operation in a disk drive

The present invention is directed to a method and apparatus for modifying a spiral profile using reference tracks written onto a disk surface of a disk drive. In one embodiment, a disk drive includes a disk surface having both a read head and a write head associated therewith. A servo track writer is provided for moving the write head and the read head relative to the disk surface. The write head, under control of the servo track writer, is used to write both a first reference track near an outer diameter of the disk surface and a second reference track near an inner diameter of the disk surface. The servo track writer is used to move the write head according to a spiral profile when writing spiral servo information onto the disk surface, and the first and second reference tracks are used to modify the spiral profile.

Method and apparatus for modifying spiral profile using reference tracks written onto a disk surface of a disk drive

A method for creating a high efficiency, error minimizing code is provided. In addition, an apparatus having a high efficiency, error minimizing code is provided. In particular, the present invention provides a high efficiency, error minimizing code for use in connection with systems having a communication channel in which identifiable dominant errors occur, and that is used to transmit data that may be usefully applied in the system even though the received signal is not exactly equal to the original signal. Furthermore, the present invention provides a code that may be used to constrain the effects of dominant errors in a communication channel.

High efficiency, error minimizing coding strategy method and apparatus

A disk drive provides manufacture test processing of itself after it is installed and operating within a computer system. The tests include flaw mapping, embedded runout compensation and final drive verification and do not interfere with normal operations of the disk drive.

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Erie, CO, United States of America

John L Seabury