International Business Machines Corporation

Hitachi Global Storage Technologies Netherlands B.v.

William John Kabelac

Steven Robert Hetzler

Mario Blaum

Mantle Man-Hon Yu

Ian L Sanders

Louis Joseph Serrano

Barry Marshall Trager

Shmuel Winograd

Shen Jen

Glen Alan Jaquette

John Stewart Best

David A Thompson

A servo write apparatus, comprising a first servo write head configured to only encode a single first magnetic dibit onto a magnetic information storage medium, wherein the first magnetic dibit comprises a first azimuthal slope. The servo write apparatus further comprises a second servo write head configured to encode one or more second magnetic dibits onto a magnetic information storage medium, wherein the second magnetic dibit comprises a second azimuthal slope, wherein the first azimuthal slope differs from the second azimuthal slope.

Servo write assembly

A method for longitudinal position (LPOS) detection in a magnetic tape storage system for storing data upon linear tape open (LTO) magnetic storage tape, which data includes odd and even 36-bit LPOS words with error correcting ability. The method includes first encoding positional information onto the tape within the 36-bit LPOS words using each LPOS word's 8-bit sync mark field, and six of each LPOS word's 4-bit symbol fields, wherein 6 of 24 total bits comprise the encoded 8-bit sync mark field: Sy, and six 4-bit symbol fields are utilized as parity bits. The magnetic tape storage system passes the LTO magnetic storage tape encoded with the odd and even LPOS words with error correcting ability longitudinally across a servo reader/writer at a known speed, decoding the encoded positional information and detecting and correcting both ambiguous bits and single erroneous bit errors.

Correcting errors in longitudinal position (LPOS) words

A method according to one embodiment includes writing monitor data to at least one block of a memory device having finite endurance and/or retention; reading the monitor data after a period of time; determining a retention behavior of the at least one block based on the reading; and outputting a result of the determining. A memory device according to one embodiment includes a plurality of memory blocks having finite endurance and/or retention, at least one of the blocks having monitor data written therein; and circuitry for addressing the blocks. A system according to one embodiment includes a memory device having finite endurance and/or retention, the memory device comprising: a plurality of memory blocks, at least one of the blocks having monitor data written therein, wherein the at least one block has been written to a plurality of times prior to writing the monitor data; and circuitry for addressing the blocks.

System, method, and computer program product for determining a retention behavior for at least one block of a memory device having finite endurance and/or retention

A method according to one embodiment includes gathering information about monitor data from a plurality of memory devices having finite endurance and/or retention, the monitor data being (i) data of known content stored in dedicated memory cells of known write cycle count, and (ii) write protected for preventing the monitor data from being overwritten with user data; analyzing the monitor data information; and taking an action relating to at least one of the devices based on the analyzing. Additional systems, methods, and computer program products are also disclosed.

System, method, and computer program product for analyzing monitor data information from a plurality of memory devices having finite endurance and/or retention

A method according to one embodiment includes gathering monitor data information from a memory device having finite endurance and/or retention, the monitor data being data of known content stored in dedicated memory cells of known write cycle count; analyzing the monitor data information; estimating a reliable life of the memory device or portion thereof based on the analysis; tracking a rate of change of at least a highest cycle count of user data; estimating when the reliable life of the memory device or portion thereof will be expended based on the tracking and the estimating; and taking an action prior to the reliable life of the memory device or portion thereof being expended. Additional systems, methods, and computer program products are also disclosed.

System, method, and computer program product for estimating when a reliable life of a memory device having finite endurance and/or retention, or portion thereof, will be expended

A sequential data storage medium, such as for example and without limitation a magnetic tape, comprising a sequence of plurality of servo patterns encoded therein, which provide lateral position information and LPOS information. Each servo pattern comprises a first burst comprising a first pulse, a second pulse, a third pulse, a fourth pulse and a fifth pulse and a second burst comprising a sixth pulse, a seventh pulse, an eighth pulse, a ninth pulse and a tenth pulse. The widths of the plurality of pulses, in combination with the spacings between the plurality of pulses, encode two bits of data.

Servo pattern architecture and method using same to improve LPOS encoding efficiency

A method according to one embodiment includes gathering monitor data information from a plurality of memory devices having finite endurance and/or retention, the monitor data being data of known content stored in dedicated memory cells of known write cycle count; analyzing the monitor data information; and taking an action relating to at least one of the devices based on the analyzing. Additional systems, methods, and computer program products are also disclosed.

The invention includes a method for longitudinal position (LPOS) detection in a magnetic tape storage system for storing data upon linear tape open (LTO) magnetic storage tape, which data includes odd and even 36-bit LPOS words with error correcting ability. The method includes steps of encoding positional information onto the magnetic storage tape within the odd and even 36-bit LPOS words using each LPOS word's 8-bit sync mark field, Sy, and six of each LPOS word's 4-bit symbol fields, L, L, LL, L, and L, wherein 6 of 24 total bits comprising the encoded 8-bit sync mark field: Sy, and six 4-bit symbol fields: L, L, LL, L, and Lare utilized as parity bits, operating the magnetic tape storage system by passing the LTO magnetic storage tape encoded with the odd and even LPOS words with error correcting ability longitudinally across a servo reader/writer at a known speed, decoding the encoded positional information by reading either two words sequentially or two words simultaneously, the simultaneous reading requiring that the LPOS words include servo band numbers and detecting and correcting both ambiguous bits and single erroneous bit errors.

A sequential data storage medium, such as for example and without limitation a magnetic tape, comprising a sequence of plurality of servo patterns encoded therein, which provide lateral position information and LPOS information. Each servo pattern comprises a first burst comprising a first pulse, a second pulse, a third pulse, a fourth pulse and a fifth pulse and a second burst comprising a sixth pulse, a seventh pulse, an eighth pulse, a ninth pulse and a tent pulse. The widths of the plurality of pulses, in combination with the spacings between the plurality of pulses, encode two bits of data.

A sequential data storage medium, such as for example and without limitation a magnetic tape, comprising a plurality of servo patterns encoded in a non-data region, wherein each of said servo patterns comprises a first subframe comprising 10 pulses, a second subframe comprising 8 pulses, and a third subframe comprising (N) pulses, wherein (N) is greater than or equal to 0. The first subframe and the second subframe do not encode any linear position ('LPOS') data. The third subframe encodes up to (N) LPOS bits.

Servo pattern architecture to uncouple position error determination from linear position information

A read clock circuit for a disk drive includes a phase-locked loop/voltage controlled oscillator (VFO/PLL) and a frequency synthesizer. The VFO/PLL receives a servo sector transition signal that is related to detected transitions in a servo sector field of a magnetic recording disk, and outputs a servo frequency signal that is synchronous to the servo sector transition signal. The frequency synthesizer receives the servo frequency signal and generates the read clock signal that is synchronous with the servo frequency signal. In a banded recording disk drive the frequency synthesizer generates a unique read clock signal for each data band.

Disk drive with servo synchronous recording

A method and apparatus for detecting typing errors of critical fixed series of characters (digits) by using at least one redundant parity digit. The invention detects the most common typing errors that involve both permutations and incorrect striking of adjacent characters during data entry via a keyboard of an electronic apparatus. The method provides warning to the data input operator when incorrect data entry occurs and optionally automatically suspends entry thereof.

Apparatus and method for verifying proper data entry and detecting common typing errors

There is disclosed an error correction and detection method and apparatus for retreiving predetermined data, e.g. servo data, from the position error signal (PES) fields of a disk in a data storage system . In the preferred embodiment the PES data such as the track number is mapped into codewords of an error correction code (ECC) which are then further divided into a set of symbols which are mapped onto a second set of bit vectors which have a constant weight. The preferred encoding method is selected to equalize the analog signal characteristics of the PES fields so that minimal, if any, change in the conventional servo detection circuitry needed to use the PES fields of the invention both as analog and digital information.

Disk drive with information encoded in the position error signal fields

A magnetic recording disk drive has head positioning servo sectors with servo sector numbers (SSNs) that are not recorded on the disk. The SSNs are encoded through the use of multiple servo sector types that are arranged in a specific sequence around the data tracks. The different servo sector types are identified by unique types of servo timing marks (STMs), which are used to locate the servo sectors. The SSNs that are used to identify the servo sectors on the track form a set or code of m fixed n-bit patterns. A SSN is determined when the STM types read from n sequential servo sectors match one of the fixed SSN pattems. A set or code of m servo sectors, where each servo sector is identified by a unique SSN pattern having length n, is denoted as an (m,n,d) code, where d is referred to as the minimum Hamming distance of the code. The Hamming distance between two patterns refers to the number of locations that are different between the two pattems.

Disk drive with sector numbers encoded by sequences of sector types

A method of detecting and correcting reading errors of track identification (TID) of a magnetic data storage disk. The method comprises a means of constructing a encoded TID which is derived from generalized Gray code. The encoded TIDs have a distance of D between the adjacent code words, and a distance of at least 2D between non-adjacent code words within a band of M TIDS. The encoded TIDs can correct up to (D&minus;1)/2 errors. The method also comprises means of encoding and decoding TIDS, and means of detecting and correcting errors with encoded TIDs.

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Morgan Hill, CA, United States of America

William John Kabelac