# US 10,770,101 B2 · Systems and methods for writing servo patterns > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,770,101 B2 - Document ID: US10770101B2 - Status: Granted - Kind: B2 - Application number: 16/256,929 - Filed: 2019-01-24 - Published: 2019-05-23 - Granted: 2020-09-08 - Earliest claimed: 2008-06-18 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: Robert G. Biskeborn; Wayne I. Imaino - Web page: https://patentgrep.com/patent/US10770101B2 ## CPC - G11B 5/5926: {recorded in separate tracks, e.g. servo tracks} - G11B 5/00813: {magnetic tapes} - G11B 5/584: for track following on tapes - G11B 15/60: Guiding record carrier (guiding devices structurally associated with magazines or cassettes G11B23/04) - G11B 2220/90: Tape-like record carriers - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract A computer program product for writing a servo track includes a computer readable storage medium having program instructions embodied therewith. The program instructions are executable by a computer. The program instructions cause the computer to monitor a lateral position of a magnetic tape passing over a servo writing head during a servo track writing operation and write servo marks to the magnetic tape. A timing of the writing of each mark is based on the monitored position of the magnetic tape. A computer program product for writing a servo track includes a computer readable storage medium having program instructions embodied therewith. The program instructions are executable by a computer. The program instructions cause the computer to optically monitor a lateral position of a magnetic tape passing over a servo writing head during a servo track writing operation. ## Claims ### Claim 1 A system, comprising: a magnetic tape having a servo track having physical characteristics of being written by a tape drive that monitors a lateral position of the magnetic tape passing over a servo writing head of the tape drive during a servo track writing operation and writes servo marks to the magnetic tape, a spacing between the servo marks being physically characteristic of variations in a timing of the writing of each servo mark made based on the monitored lateral position of the magnetic tape; and the tape drive configured to: monitor, by the tape drive, the lateral position of the magnetic tape passing over the servo writing head during the servo track writing operation, and write, by the tape drive, servo marks to the magnetic tape, the timing of the writing of each mark being based on the monitored lateral position of the magnetic tape. ### Claim 2 (depends on 1) A system as recited in claim 1, wherein each servo mark is individually written. ### Claim 3 (depends on 1) A system as recited in claim 1, wherein the tape drive is configured to: monitor, by the tape drive, a velocity of the magnetic tape relative to the head, wherein the timing of the writing of each mark is further based on the monitored velocity of the magnetic tape. ### Claim 4 (depends on 1) A system as recited in claim 1, wherein the tape drive is configured to: reduce a height of the written servo marks, the height of the written servo marks being measured in a direction perpendicular to a direction of tape travel. ### Claim 5 (depends on 1) A system as recited in claim 1, wherein the head is stationary during the servo writing operation. ### Claim 6 (depends on 1) A system as recited in claim 1, wherein the servo marks comprise a series of magnetically defined bars. ### Claim 7 (depends on 6) A system as recited in claim 6, wherein the servo track comprises a series of base sets of magnetically defined bars, each base set comprising two bars oriented at different angles with respect to a direction of tape travel. ### Claim 8 (depends on 6) A system as recited in claim 6, wherein the servo track comprises a series of base sets of magnetically defined bars, each base set comprising three bars, each base set comprising at least two bars oriented at different angles with respect to a direction of tape travel. ### Claim 9 (depends on 6) A system as recited in claim 6, wherein the servo track comprises a series of base sets of magnetically defined bars, each base set comprising at least four bars, each base set comprising at least two bars oriented at different angles with respect to a direction of tape travel. ### Claim 10 (depends on 6) A system as recited in claim 6, wherein an angle between at least some of the bars is greater than 0 degrees and less than 180 degrees. ### Claim 11 (depends on 6) A system as recited in claim 6, wherein an angle between at least some of the bars is less than about 50 degrees. ### Claim 12 (depends on 6) A system as recited in claim 6, wherein multiple servo tracks are present on the magnetic tape, wherein a distance between the servo tracks is less than about 3 mm. ### Claim 13 (depends on 6) A system as recited in claim 6, wherein multiple servo tracks are present on the magnetic tape, wherein a distance between the servo tracks is less than about 1.5 mm. ### Claim 14 (depends on 6) A system as recited in claim 6, wherein multiple servo tracks are present on the magnetic tape, wherein the distance between the servo tracks is less than about 0.75 mm. ### Claim 15 (depends on 6) A system as recited in claim 6, wherein one the servo tracks has data encoded therein. ### Claim 16 (depends on 6) A system as recited in claim 6, wherein the lateral position of the magnetic tape is optically monitored. ### Claim 17 A system, comprising: a magnetic tape having a servo track having physical characteristics of being written by a tape drive that monitors a lateral position and velocity of the magnetic tape passing over a servo writing head of the tape drive during a servo track writing operation and writes servo marks to the magnetic tape, a spacing between the servo marks being physically characteristic of variations in a timing of the writing of each servo mark made based on the monitored lateral position and velocity of the magnetic tape; and the tape drive configured to: optically monitor, by the tape drive, the lateral position of a magnetic tape passing over a servo writing head during a servo track writing operation, monitor, by the tape drive, a velocity of the magnetic tape relative to the head, write, by the tape drive, the servo marks to the magnetic tape, wherein the servo marks are magnetically defined bars arranged in base sets, each base set comprising at least two bars oriented at different angles with respect to a direction of tape travel, adjust, by the tape drive, a timing of the writing of each of the servo marks based on the monitored lateral position of the magnetic tape, and further adjust, by the tape drive, the timing of the writing of each of the servo marks based on the monitored velocity of the magnetic tape. ### Claim 18 (depends on 17) A system as recited in claim 17, wherein each servo mark is individually written. ### Claim 19 A tape drive for writing a servo track, the tape drive being configured to: read, by the tape drive, a previously-written servo pattern on a magnetic tape; monitor, by the tape drive, a lateral position of a magnetic tape during the reading; deduce, by the tape drive, written in noise in the servo pattern; and write, by the tape drive, servo marks to the magnetic tape over the written in noise.