# US 2019/0371364 A1 · Shortening the average reposition time to the beginning of files in a magnetic tape > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0371364 A1 - Document ID: US20190371364A1 - Status: Published application - Kind: A1 - Application number: 16/262,072 - Filed: 2019-01-30 - Published: 2019-12-05 - Earliest claimed: 2018-06-05 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: Tohru Hasegawa; HIROSHI ITAGAKI; SOSUKE MATSUI; Shinsuke Mitsuma; TSUYOSHI MIYAMURA; NORIKO YAMAMOTO - Web page: https://patentgrep.com/patent/US20190371364A1 ## CPC - G11B 27/107: {of operating tapes} - G11B 5/00821: {using stationary heads} - G11B 5/5513: {Specially adapted for transducing in both travelling directions of tape} - G11B 2020/10916: {Seeking data on the record carrier for preparing an access to a specific address} - 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 system accesses metadata on a file system of the magnetic tape, where the metadata comprising one or more fields enabling to determine a longitudinal position (LPOS) of one or more files located on the magnetic tape. The system determines the LPOS of the one or more files located on the magnetic tape. The system determines an optimal location of the head on the magnetic tape based on computing an average value to the determined LPOS of the one or more files located on the magnetic tape and moves the head on the magnetic tape to the optimal location. ## Claims ### Claim 1 A method for shortening a reposition time of a head on a magnetic tape, the method comprising: determining a longitudinal position (LPOS) of one or more files located on the magnetic tape; determining an optimal location of the head on the magnetic tape based on computing an average travel distance to the determined LPOS of the one or more files located on the magnetic tape; and relocating the head on the magnetic tape to the optimal location. ### Claim 2 (depends on 1) The method of claim 1, wherein determining the LPOS of the one or more files located on the magnetic tape comprises determining a beginning of each one of the one or more files located on the magnetic tape based on converting a start block and a length of a data to the LPOS. ### Claim 3 (depends on 2) The method of claim 2, wherein determining an optimal location of the head on the magnetic tape based on computing an average travel distance to the determined LPOS of the one or more files located on the magnetic tape further comprises: calculating the travel distance value based on an equation D avg  ( x ) = ∑ i = 1 n   x - p i  n , wherein n represents a number of the one or more files, and wherein pi represents the beginning of each one of the one or more files located on the magnetic tape in LPOS; and analyzing locations x on the magnetic tape and determining an xmin based on the average travel distance Davg(x). ### Claim 4 (depends on 3) The method of claim 3, wherein relocating the head on the magnetic tape to the optimal location further comprises relocating the magnetic tape to the xmin based on determining no access the file request was received for more than predetermined timeframe. ### Claim 5 (depends on 1) The method of claim 1, wherein determining an optimal location of the head on the magnetic tape based on computing an average travel distance to the determined LPOS of the one or more files located on the magnetic tape further comprises: determining one or more weights based on a number of times each one of the one or more files were previously accessed; calculating the average travel distance of each one of the one or more files located on the magnetic tape in LPOS; and determining the optimal location of the head on the magnetic tape based on the average travel distance. ### Claim 6 (depends on 1) The method of claim 1, wherein calculating the average travel distance of each one of the one or more files located on the magnetic tape in LPOS further comprises: calculating the average travel distance based on an equation D avg  ( x ) = ∑ i = 1 n   x - p i  × ( 1 + a i ) n + ∑ i = 1 n  a i , wherein ai represents the one or more weights, wherein n represents a number of the one or more files, and wherein pi represents a beginning of the each one of the one or more files located on the magnetic tape in LPOS; and analyzing locations x on the magnetic tape and determining an xmin based on the average travel distance Davg(X). ### Claim 7 (depends on 6) The method of claim 6, wherein relocating the head on the magnetic tape to the optimal location further comprises relocating the magnetic tape to the xmin based on determining no access the file request was received for more than predetermined timeframe. ### Claim 8 A computer system for shortening a reposition time of a head on a magnetic tape, the computer system comprising: one or more processors, one or more computer-readable memories, one or more computer-readable tangible storage medium, and program instructions stored on at least one of the one or more tangible storage medium for execution by at least one of the one or more processors via at least one of the one or more memories, wherein the computer system is capable of performing a method comprising: determining a longitudinal position (LPOS) of one or more files located on the magnetic tape; determining an optimal location of the head on the magnetic tape based on computing an average travel distance to the determined LPOS of the one or more files located on the magnetic tape; and relocating the head on the magnetic tape to the optimal location. ### Claim 9 (depends on 8) The computer system of claim 8, wherein determining the LPOS of the one or more files located on the magnetic tape comprises determining a beginning of each one of the one or more files located on the magnetic tape based on converting a start block and a length of a data to the LPOS. ### Claim 10 (depends on 9) The computer system of claim 9, wherein determining an optimal location of the head on the magnetic tape based on computing an average travel distance to the determined LPOS of the one or more files located on the magnetic tape further comprises: calculating the travel distance value based on an equation D avg  ( x ) = ∑ i = 1 n   x - p i  n , wherein n represents a number of the one or more files, and wherein pi represents the beginning of each one of the one or more files located on the magnetic tape in LPOS; and analyzing locations x on the magnetic tape and determining an xmin based on the average travel distance Davg(x). ### Claim 11 (depends on 10) The computer system of claim 10, wherein relocating the head on the magnetic tape to the optimal location further comprises relocating the magnetic tape to the xmin based on determining no access the file request was received for more than predetermined timeframe. ### Claim 12 (depends on 8) The computer system of claim 8, wherein determining an optimal location of the head on the magnetic tape based on computing an average travel distance to the determined LPOS of the one or more files located on the magnetic tape further comprises: determining one or more weights based on a number of times each one of the one or more files were previously accessed; calculating the average travel distance of each one of the one or more files located on the magnetic tape in LPOS; and determining the optimal location of the head on the magnetic tape based on the average travel distance. ### Claim 13 (depends on 8) The computer system of claim 8, wherein calculating the average travel distance of each one of the one or more files located on the magnetic tape in LPOS further comprises: calculating the average travel distance based on an equation D avg  ( x ) = ∑ i = 1 n   x - p i  × ( 1 + a i ) n + ∑ i = 1 n  a i , wherein ai represents the one or more weights, wherein n represents a number of the one or more files, and wherein pi represents a beginning of the each one of the one or more files located on the magnetic tape in LPOS; and analyzing locations x on the magnetic tape and determining an xmin based on the average travel distance Davg(x). ### Claim 14 (depends on 13) The computer system of claim 13, wherein relocating the head on the magnetic tape to the optimal location further comprises relocating the magnetic tape to the xmin based on determining no access the file request was received for more than predetermined timeframe. ### Claim 15 A computer program product for shortening a reposition time of a head on a magnetic tape, the computer program product comprising: one or more computer-readable tangible storage medium and program instructions stored on at least one of the one or more tangible storage medium, the program instructions executable by a processor, the program instructions comprising: program instructions to determining a longitudinal position (LPOS) of one or more files located on the magnetic tape; program instructions to determine an optimal location of the head on the magnetic tape based on computing an average travel distance to the determined LPOS of the one or more files located on the magnetic tape; and program instructions to relocate the head on the magnetic tape to the optimal location. ### Claim 16 (depends on 15) The computer program product of claim 15, wherein program instructions to determine the LPOS of the one or more files located on the magnetic tape comprises program instructions to determine a beginning of each one of the one or more files located on the magnetic tape based on converting a start block and a length of a data to the LPOS. ### Claim 17 (depends on 16) The computer program product of claim 16, wherein program instructions to determine an optimal location of the head on the magnetic tape based on computing an average travel distance to the determined LPOS of the one or more files located on the magnetic tape further comprises: program instructions to calculate the travel distance value based on an equation D avg  ( x ) = ∑ i = 1 n   x - p i  n , wherein n represents a number of the one or more files, and wherein pi represents the beginning of each one of the one or more files located on the magnetic tape in LPOS; and program instructions to analyze locations x on the magnetic tape and program instructions to determine an xmin based on the average travel distance Davg(x). ### Claim 18 (depends on 17) The computer program product of claim 17, wherein program instructions to relocate the head on the magnetic tape to the optimal location further comprises program instructions to relocate the magnetic tape to the xmin based on determining no access the file request was received for more than predetermined timeframe. ### Claim 19 (depends on 15) The computer program product of claim 15, wherein program instructions to determine an optimal location of the head on the magnetic tape based on computing an average travel distance to the determined LPOS of the one or more files located on the magnetic tape further comprises: program instructions to determine one or more weights based on a number of times each one of the one or more files were previously accessed; program instructions to calculate the average travel distance of each one of the one or more files located on the magnetic tape in LPOS; and program instructions to determine the optimal location of the head on the magnetic tape based on the average travel distance. ### Claim 20 (depends on 15) The computer program product of claim 15, wherein program instructions to calculate the average travel distance of each one of the one or more files located on the magnetic tape in LPOS further comprises: program instructions to calculate the average travel distance based on an equation D avg  ( x ) = ∑ i = 1 n   x - p i  × ( 1 + a i ) n + ∑ i = 1 n  a i , wherein ai represents the one or more weights, wherein n represents a number of the one or more files, and wherein pi represents a beginning of the each one of the one or more files located on the magnetic tape in LPOS; and program instructions to analyze locations x on the magnetic tape and determining an xmin based on the average travel distance Davg(x).