JP2006079680A - Information medium search device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information reproducing device which can instantly decide the end of the movement of the read element and quickly process the read start procedures. <P>SOLUTION: The device makes the same interleave processing to the specific attached information as the attached information recorded on an information medium 107 when it is decided to move the read element 101 to the specific attached information, and immediately compares the already interleaved specific attached information with the interleaved attached information read from the information medium 107. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to control of an information reproducing apparatus, and particularly relates to control of a search apparatus for attached information recorded in a storage medium.

  In general, information recorded on an information medium such as an optical disc or a tape includes data information such as music, images, or program data read out from the information medium and used on the information medium. Attached information in which the arrangement number and the characteristics of the data information are written is included. Depending on the recording format of the information medium, the attached information may be recorded in a form subjected to a rearrangement process called interleaving as shown in FIG. 5 in order to reduce errors during reading. As an information medium in which attached information is recorded in an interleaved form, for example, there is a Blu-Ray Disc (for example, see Non-Patent Document 1).

  In the reproduction of an information medium, particularly a disk medium, generally, when reading arbitrary data information recorded on the information medium, a reading element (for example, an optical pickup or a magnetic head) of the information medium is read. Predetermined when the information is moved at high speed immediately before the target information, and then the attached information is read to determine whether the reading element has moved to an accurate position. The process of reading the information is performed.

  FIG. 4 is a diagram showing a configuration of a reading element movement end determination unit 400 in a conventional information medium search device. The movement end determination unit 400 determines whether or not the reading element has accurately moved to a target position, and includes a reading element 401, a reading attached information storage unit 402, a deinterleave circuit 403, and a control circuit. 404, a target attached information storage unit 405, and a comparison circuit 406. The reading element 401 reads data information and interleaved read attached information d1 from an information medium 407 such as an optical disk. The reading attachment information storage unit 402 stores the interleaved reading attachment information d1 read by the reading element 401. The deinterleave circuit 403 deinterleaves the read attached information d1 and outputs attached information d2. The control circuit 404 outputs target ancillary information d3 indicating the movement target destination of the reading element 401, and determines the end of movement of the reading element 401 based on the output from the comparison circuit 406. The target attached information storage unit 405 stores the target attached information d3 output from the control circuit 404. The comparison circuit 406 compares the attached information d2 and the target attached information d3.

Next, the operation will be described.
When a reproduction request for predetermined data information is generated by an instruction from the outside of the information reproducing apparatus, the control circuit 404 outputs target auxiliary information d3 corresponding to the auxiliary information attached to the data information, and stores the target auxiliary information. Stored in the unit 405. Then, the reading element 401 is moved and stopped by rough control to near the target attached information d3 on the information medium. The reading element 401 reads the read attached information d1 that has been interleaved at the moving destination, and stores the read attached read information d1 in the read attached information storage unit 402. The deinterleave circuit 403 deinterleaves the read-attached information d1 that has been interleaved, and outputs this to the comparison circuit 406 as attached information d2.

The comparison circuit 406 compares the values of the target attribute information d3 stored in the target attribute information storage unit 405 and the attribute information d2 output from the deinterleave circuit 403, and if these values match, The control circuit 404 is notified of the match. Upon receiving notification that the values of the attached information d2 and the target attached information d3 match, the control circuit 404 determines that the accurate movement of the reading element 401 has been completed.
“Next Generation Optical Disc Dismantling New Book”, Nikkei Electronics Books, published on October 7, 2003 (International Standard Book Number: ISBN 4-8222-0241-0), p. 72, FIG.

  However, even if the reading element 401 of the information medium 407 is moved by rough control to the vicinity of the target attached information d3 and the attached information is read from the information medium at the movement destination in the conventional information medium search device, the attached information is read. Since the information d1 is interleaved, it cannot be immediately determined whether or not the reading element 401 has moved to the target position. That is, since it is possible to determine whether or not it has been possible to move to the target position for the first time after performing the deinterleaving process on the read reading attached information d1, the deinterleaving process starts moving the reading element 401 and reading data information. This is a process that hinders speeding up of the process.

  The present invention has been made to solve the above-described problem, and provides an information medium search device capable of immediately determining the end of movement of a reading element and quickly performing a data information reading start process. With the goal.

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present application is an information medium storing address information which is given for each information unit and has been rearranged within one information unit. In the information medium retrieval device for retrieving the address information given to the information unit desired to be read, a reading element that reads the address information from the information medium to obtain the read address information, and a read request from the information medium The control circuit for outputting the target address information corresponding to the address information of the information unit for which information has been made, and the target address information are rearranged by the same procedure as the rearrangement completed within the one information unit An interleave circuit, and a comparison circuit that compares the read address information with the target address information output from the interleave circuit, and the control circuit outputs the comparison circuit. Based on the reading device and judging whether the moved into position.

  Further, the invention according to claim 2 of the present application desires to read out from the information medium storing the address information given for each information unit and subjected to rearrangement that is completed within one information unit. In the information medium search device for searching for the address information given to the information unit, a reading element that reads the address information from the information medium to obtain the reading address information, and the one information unit for the reading address information The de-interleaving circuit that performs re-ordering and the read-address information or the read-address information that has been re-ordered by the de-interleave circuit in a procedure reverse to the re-ordering procedure completed within A first selection circuit for selecting and outputting based on the control signal and destination address information corresponding to the address information of the information unit requested to be read from the information medium The control circuit and the destination address information are rearranged by the same procedure as the rearrangement completed within the one information unit, and the rearrangement is performed by the destination address information or the interleave circuit. A second selection circuit that selects and outputs any of the performed destination address information based on the predetermined control signal; an output value from the first selection circuit; and an output from the second selection circuit A comparison circuit for comparing the values, and the control circuit determines whether or not the reading element has moved to a predetermined reading position based on an output of the comparison circuit.

  Further, the invention according to claim 3 of the present application desires to read out from the information medium storing the address information which is given for each information unit and has been rearranged within one information unit. In the information medium search method for searching for the address information given to an information unit, an address information reading step of reading the address information from the information medium to obtain read address information, and a read request from the information medium are made. A destination address information output step for outputting destination address information corresponding to the address information of the information unit, and interleaving for rearranging the destination address information in the same procedure as the rearrangement completed within the one information unit A comparison step for comparing the read address information with the destination address information sorted in the interleaving step, and the comparison step Tsu based on the comparison result obtained in flop, the information medium reading information from the reading device is characterized in that it comprises a determination step of determining whether to move to a predetermined reading position.

  Further, the invention according to claim 4 of the present application desires to read out from the information medium storing the address information which is given for each information unit and has been rearranged within one information unit. In an information medium search method for searching for the address information given to an information unit, an address information reading step of reading the address information from the information medium to obtain read address information, and for the read address information, In a procedure opposite to the rearrangement procedure completed within the information unit, either the deinterleaving step for performing the rearrangement and the read address information or the read address information subjected to the rearrangement by the deinterleave circuit, A first selection step for selecting and outputting based on a predetermined control signal, and an address corresponding to the address information of the information unit for which a read request is made from the information medium. A destination address information output step for outputting address information, an interleaving step for rearranging the destination address information in the same procedure as the rearrangement completed within the one information unit, and the destination address information, or A second selection step of selecting and outputting any of the target address information rearranged by the interleave circuit based on the predetermined control signal; and an output value output in the first selection step And a comparison step for comparing the output value output in the second selection step and a reading element for reading information from the information medium at a predetermined reading position based on the comparison result obtained in the comparison step. And a determination step of determining whether or not it has moved.

  According to the invention according to claim 1 of the present application, information desired to be read from the information medium storing the address information which is given for each information unit and has been rearranged within one information unit. In the information medium search device for searching for the address information given to a unit, a reading element that reads the address information from the information medium to obtain the reading address information, and an information unit for which a read request is made from the information medium A control circuit for outputting destination address information corresponding to the address information; an interleave circuit for rearranging the destination address information in the same procedure as the rearrangement completed within the one information unit; and the reading address A comparison circuit for comparing information and target address information output from the interleave circuit, the control circuit based on the output of the comparison circuit Since it is determined whether or not the child has moved to a predetermined reading position, the time required for deinterleaving, which has been required in the past, can be omitted, thereby reducing the time required for searching for attached information. It becomes possible to do.

  The invention according to claim 2 of the present application is information that is desired to be read out from an information medium storing address information that is provided for each information unit and that has been rearranged within one information unit. In the information medium search device for searching for the address information given to a unit, a reading element that reads the address information from the information medium and obtains the reading address information, and within the one information unit for the reading address information The de-interleaving circuit for performing the re-ordering, and the reading address information or the reading address information subjected to the re-ordering by the de-interleaving circuit in the reverse order of the re-ordering procedure completed in A first selection circuit for selecting and outputting based on the control signal; and outputting destination address information corresponding to the address information of the information unit requested to be read from the information medium. The control circuit and the destination address information are rearranged in the same procedure as the rearrangement completed within the one information unit, and the rearrangement is performed by the destination address information or the interleave circuit. A second selection circuit that selects and outputs one of the destination address information based on the predetermined control signal, an output value from the first selection circuit, and an output value from the second selection circuit And the control circuit determines whether or not the reading element has moved to a predetermined reading position based on the output of the comparison circuit. It is possible to optimize the search accuracy and search speed of attached information according to the reading characteristics of data from the information medium, such as the characteristics of the element, the playback speed, and the reading error occurrence status. .

  Further, according to the invention of claim 3 of the present application, it is desired to read out from the information medium in which the address information given for each information unit and rearranged within one information unit is stored is stored. In the information medium search method for searching the address information given to the information unit to be read, an address information reading step of reading the address information from the information medium to obtain read address information, and a read request from the information medium are made. The target address information output step for outputting the target address information corresponding to the address information of the information unit, and the target address information are rearranged in the same procedure as the rearrangement completed within the one information unit. An interleaving step, a comparing step for comparing the read address information with the destination address information rearranged in the interleaving step, and the ratio It has been conventionally required since it includes a determination step for determining whether or not the reading element for reading information from the information medium has moved to a predetermined reading position based on the comparison result obtained in the step. The time required for deinterleaving can be omitted, which makes it possible to reduce the time required for searching for attached information.

  According to the invention of claim 4 of the present application, it is desired to read from the information medium storing the address information given for each information unit and subjected to rearrangement that is completed within one information unit. In the information medium search method for searching for the address information given to the information unit to be read, the address information reading step for obtaining the read address information by reading the address information from the information medium, and for the read address information, the 1 One of the de-interleaving step for performing re-ordering and the read address information or the read address information that has been re-ordered by the de-interleave circuit is the reverse of the re-ordering procedure completed within one information unit. A first selection step of selecting and outputting based on a predetermined control signal, and address information of an information unit for which a read request is made from the information medium A destination address information output step for outputting destination address information, an interleaving step for rearranging the destination address information in the same procedure as the rearrangement completed within the one information unit, the destination address information, Alternatively, a second selection step of selecting and outputting any of the destination address information rearranged by the interleave circuit based on the predetermined control signal, and an output output in the first selection step A reading step for reading information from the information medium based on a comparison step for comparing the value and the output value output in the second selection step, and a comparison result obtained in the comparison step; A determination step for determining whether or not the information has been moved to, the characteristics of the information medium or the reading element, or the reproduction speed or reading error. Such raw state, in accordance with the read status of the data from the information medium, it is possible to optimize the search accuracy and search speed of the additional information.

(Embodiment 1)
FIG. 1 is a diagram illustrating a configuration of a reading element movement end determination unit 100 in an attached information search unit according to Embodiment 1 of the present invention.

  The movement end determination unit 100 of the first embodiment includes a reading element 101, a reading attached information storage unit 102, a control circuit 103, an interleave circuit 104, a target attached information storage unit 105, and a comparison circuit 106. is doing. The difference between the movement end determination unit 100 according to the first embodiment and the conventional movement end determination unit 400 is that the deinterleave circuit 403 provided in the conventional movement end determination unit 400 is deleted and the control circuit The interleave circuit 104 is added to the subsequent stage of 103.

  The reading element 101 reads out attached information including data information and address information of the data information from an information medium 107 such as an optical disk. Here, in the information medium 107 according to the first embodiment, the attached information subjected to the rearrangement (interleaving) processing as shown in FIG. 5 is recorded. Therefore, the reading element 101 is not rearranged. The attached attached information is read as read attached information d1. The reading attached information storage unit 102 stores the reading attached information d1 read by the reading element 101.

  The control circuit 103 outputs target ancillary information d3 representing the movement target of the reading element 101, and determines the end of movement of the reading element 101 based on the output from the comparison circuit 106. The interleave circuit 104 performs predetermined interleaving on the target attached information d3 output from the control circuit 103, and outputs it as moving target attached information d4. The target attached information storage unit 105 stores the moving target attached information d4 output from the interleave circuit 104. The comparison circuit 106 compares the read attached information d1 and the movement target attached information d4.

The operation of the movement end determination unit 100 configured as described above will be described below.
When a reproduction request for predetermined data information is generated by an instruction from the outside of the information reproducing apparatus, the control circuit 103 outputs the target attached information d3 to the interleave circuit 104. The interleave circuit 104 performs interleaving processing similar to the interleaving procedure applied to the auxiliary information recorded on the information medium 107 for the target auxiliary information d3, and uses this as moving target auxiliary information d4 as a target auxiliary information storage unit It stores in 105.

  The control circuit 103 moves and stops the reading element 101 with rough control up to near the target attached information d3. The reading element 101 reads the read attached information d1 at the movement destination and stores it in the read attached information storage unit 102. The comparison circuit 106 compares the values of the interleaved movement target attachment information d4 stored in the target attachment information storage unit 105 and the read attachment information d1 stored in the reading attachment information storage unit 102, and compares these values. If the values match, the control circuit 103 is notified that the values match. When the control circuit 103 receives a notification that the values of the read attached information d1 and the movement target attached information d4 match, the reading element 101 has moved to an accurate position for reading the data information for which a reproduction request has been made. Judge that.

  Hereinafter, the effects of the present invention will be described in detail.

  FIG. 2A is a diagram showing the flow of the movement end determination process by the conventional movement end determination unit 400 in time series, and FIG. 2B is the movement end determination unit 100 according to the first embodiment. It is a figure showing the flow of a movement end determination process in time series. In FIG. 2, t1 is a search start time and a movement start time point of the reading elements 101 and 401, t2 is a movement end determination start time of the reading element 101, and t3 is a reading attachment time point. The reading end point of the information d1 is indicated, and t4 and t5 indicate the searching end point, respectively.

  As shown in FIG. 2A, according to the process by the conventional movement end determination unit 400, the search is started at t1, the reading element 401 is moved, and then reading of the attached information is started from t2. . When reading of the read attached information d1 is completed at t3, deinterleave processing of the read attached information d1 is performed. When deinterleave processing is completed at t4, comparison of the attached information d2 and d3 and a movement end determination are started.

  On the other hand, in the present invention, since the target attached information d3 has already been determined at the time t1 when the search is started, as shown in FIG. 2B, the interleaving process for the target attached information d3 may be started at t1. Is possible. Here, normally, the time required for moving the reading element 101 and the time required for interleaving depend on the characteristics of the reading element 101 and the contents of the interleaving, but the movement of the reading element 101 is more common. In addition, since the interleaving process and the movement of the reading element 101 are performed in parallel, the interleave circuit 104 moves the attached target information by t2 until the movement of the reading element 101 is completed. d4 can be generated. For this reason, at time t3 when the reading of the reading attached information d1 is completed, the comparison of the reading attached information d1 and d4 and the movement end determination can be started, and thus the time t4- required for the conventional deinterleaving process can be started. t3 can be omitted, and the time required to complete the search can be shortened.

  As described above, in the first embodiment, when the movement of the reading element 101 to the data information for which the reading process request is made is determined, a target that is a target when the reading element 101 moves to the predetermined data information. The attached information d3 is subjected to the same interleaving process as the interleaving process performed on the address information stored in the storage medium, and the read attached information d1 read from the information medium 101 and the target attached information d3 after the interleaving process Are immediately compared to determine the end of movement of the reading element 101, so that the time required for deinterleaving, which has been required in the past, can be omitted, thereby reducing the time required for searching for attached information. It becomes possible to do.

(Embodiment 2)
FIG. 3 is a diagram illustrating a configuration of the movement end determination unit 300 of the reading element 101 in the attached information search unit according to Embodiment 2 of the present invention. In FIG. 3, the same components as those in FIGS. 1 and 4 are denoted by the same reference numerals, and the description thereof is omitted.

  The movement end determination unit 300 according to the second embodiment is provided with a deinterleave circuit 403 at the subsequent stage of the read attached information storage unit 102 in the movement end determination unit 100 according to the first embodiment. The attached information search method and the attached information search method of the first embodiment are switched according to an instruction from the control circuit 103.

  In FIG. 3, reference numeral 301 denotes a first selection circuit, which receives the read attached information d 1 output from the read attached information storage unit 102 and the attached information d 2 output from the deinterleave circuit 403. Based on the output control signal s1, either the read attached information d1 or the attached information d2 is selectively output to the comparison circuit 106. Reference numeral 302 denotes a second selection circuit that receives as input the target attached information d3 output from the control circuit 103 and the movement target attached information d4 output from the interleave circuit 104, and outputs a control signal output from the control circuit 103. Based on s1, either the target attached information d3 or the moving target attached information d4 is selectively output to the comparison circuit 106.

  In addition, the control circuit 303 according to the second embodiment provides a control signal s1 for determining the auxiliary information to be output by each selection circuit to the first selection circuit 301 and the second selection circuit 302. Output. The output of the control signal s1 is switched according to the state of reading data from the information medium 101, such as the characteristics of the information medium 101 and the reading element 101, the reproduction speed, and the occurrence state of a reading error.

The operation of the movement end determination unit 300 configured as described above will be described below.
When a reproduction request for predetermined data information is generated by an instruction from the outside of the information reproducing apparatus, the control circuit 303 outputs the target attached information d3 to the interleave circuit 104 and the second selection circuit 302. The interleave circuit 104 performs interleaving on the target attached information d3 as in the first embodiment, and outputs this to the second selection circuit 302 as moving target attached information d4.

  Further, the control circuit 303 moves and stops the reading element 101 of the information medium 107 to the vicinity of the target attached information d3 by rough control, and reads and attaches the interleaved read attached information d1 read at the moving destination. The information is stored in the information storage unit 102. The read adjunct information d1 stored in the read adjunct information storage unit 102 is output to the first selection circuit 301 and is also output to the deinterleave circuit 403 in the same manner as in the conventional example, and deinterleave processing is performed. After that, it is output to the first selection circuit 301 as the attached information d2.

  The control circuit 303 switches and outputs the control signal s1 according to the information data reading status of the information reproducing apparatus. For example, in the case of switching the output of the control signal s1 according to the reproduction double speed, if the reproduction double speed is fast, there is a high possibility that a reading error will occur. Since it is necessary to detect the end of movement, the control circuit 303 causes the first selection circuit 301 to select the attached information d2 that has been deinterleaved, and the second selection circuit 302 A control signal s1 for selecting the target attached information d3 is output. In this case, the first selection circuit 301 receives the control signal s1 and outputs the attached information d2 to the comparison circuit 106, and the second selection circuit 302 receives the control signal s1 and receives the target attachment. Information d3 is output to the comparison circuit 106. The comparison circuit 106 compares the attached information d2 and the target attached information d3, and outputs the result to the control circuit 303, as in the conventional movement end determination.

  On the other hand, when the reproduction double speed is low, the possibility of occurrence of a reading error is low, and it takes time to read the attached information from the information medium as compared with the case where the reproduction double speed is fast. It is necessary to reduce the search time by using the movement end determination method. For this reason, the control circuit 303 causes the first selection circuit 301 to select the read attached information d1 and causes the second selection circuit 302 to select it. Then, the control signal s1 is output so as to select the interleaved movement target attached information d4. In this case, the first selection circuit 301 receives the control signal s1 and outputs the read attached information d1 to the comparison circuit 106, and the second selection circuit 302 receives the control signal s1 and moves. The target attached information d4 is output to the comparison circuit 106. The comparison circuit 106 compares the read attached information d1 and the movement target attached information d4 as in the first embodiment, and outputs the result to the control circuit 303.

  As described above, in the second embodiment, the conventional movement end determination method for comparing the target attached information d3 and the deinterleaved attached information d2, and the reading attached information d1 and the moving target attached information d4 are compared. Since the movement end determination method according to the first embodiment is switched according to an instruction from the control circuit 103, data from the information medium 107 such as characteristics of the information medium 107 and the reading element 101, a reproduction speed and a reading error occurrence state, etc. It is possible to optimize the search accuracy and the search speed of the attached information according to the reading status of.

  The information reproducing apparatus according to the present invention has a high-speed reproduction address search function, and is useful for disk media reproducing apparatuses such as optical disks. It can also be applied to uses such as tape media playback devices.

It is a figure which shows the structure of the movement end determination part of Embodiment 1 of this invention. It is a figure for demonstrating the effect by Embodiment 1 of this invention. It is a figure which shows the structure of the movement end determination part of Embodiment 2 of this invention. It is a figure which shows the structure of the conventional movement end determination part. It is a figure for demonstrating an interleaving process.

Explanation of symbols

101, 401 Reading element 102, 402 Reading attached information storage unit 103, 303, 404 Control circuit 104 Interleaving circuit 105 405 Target attached information storing circuit 106, 406 Comparison circuit 107, 407 Information medium 301, 302 Selection circuit 403 Deinterleave circuit d1 Reading attached information d2 attached information d3 target attached information d4 moving target attached information s1 control signal

Claims (4)

Information for searching for the address information given to the information unit desired to be read from the information medium storing the address information which is given for each information unit and has been rearranged in one information unit. In the media search device,
A reading element that reads the address information from the information medium and obtains reading address information;
A control circuit for outputting destination address information corresponding to address information of an information unit for which a read request is made from the information medium;
An interleave circuit for performing rearrangement on the target address information in the same procedure as the rearrangement completed within the one information unit;
A comparison circuit for comparing the read address information and the target address information output from the interleave circuit,
The control circuit determines whether the reading element has moved to a predetermined reading position based on the output of the comparison circuit.
An information medium search device characterized by that. Information for searching for the address information given to the information unit desired to be read from the information medium storing the address information which is given for each information unit and has been rearranged in one information unit. In the media search device,
A reading element that reads the address information from the information medium and obtains reading address information;
A deinterleaving circuit for performing reordering on the read address information in a procedure reverse to the reordering procedure completed within the one information unit;
A first selection circuit that selects and outputs either the reading address information or the reading address information rearranged by the deinterleave circuit based on a predetermined control signal;
A control circuit for outputting destination address information corresponding to address information of an information unit for which a read request is made from the information medium;
An interleave circuit for performing rearrangement on the target address information in the same procedure as the rearrangement completed within the one information unit;
A second selection circuit for selecting and outputting either the target address information or the target address information rearranged by the interleave circuit based on the predetermined control signal;
A comparison circuit that compares an output value from the first selection circuit with an output value from the second selection circuit;
The control circuit determines whether the reading element has moved to a predetermined reading position based on the output of the comparison circuit.
An information medium search device characterized by that. Information for searching for the address information given to the information unit desired to be read from the information medium storing the address information which is given for each information unit and has been rearranged in one information unit. In the media search method,
An address information reading step of reading the address information and obtaining read address information from the information medium;
A destination address information output step for outputting destination address information corresponding to the address information of the information unit for which a read request is made from the information medium;
An interleaving step for rearranging the target address information in the same procedure as the rearrangement completed within the one information unit;
A comparison step for comparing the read address information with the destination address information that has been sorted in the interleaving step;
A determination step of determining whether or not a reading element that reads information from the information medium has moved to a predetermined reading position based on a comparison result obtained in the comparison step;
An information medium search method characterized by the above. Information for searching for the address information given to the information unit desired to be read from the information medium storing the address information which is given for each information unit and has been rearranged in one information unit. In the media search method,
An address information reading step of reading the address information and obtaining read address information from the information medium;
A deinterleaving step for rearranging the read address information in a procedure reverse to the rearrangement procedure completed within the one information unit;
A first selection step of selecting and outputting either the read address information or the read address information rearranged by the deinterleave circuit based on a predetermined control signal;
A destination address information output step for outputting destination address information corresponding to the address information of the information unit for which a read request is made from the information medium;
An interleaving step for rearranging the target address information in the same procedure as the rearrangement completed within the one information unit;
A second selection step of selecting and outputting either the target address information or the target address information rearranged by the interleave circuit based on the predetermined control signal;
A comparison step for comparing the output value output in the first selection step with the output value output in the second selection step;
A determination step of determining whether or not a reading element that reads information from the information medium has moved to a predetermined reading position based on a comparison result obtained in the comparison step;
An information medium search method characterized by the above.

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