JP2008293195A - Terminal for information delivery system, information processing program and information processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information delivery system, for quickly receiving a desired content on a requester RQ by delivering content information between terminals, while considering the operating state in a content holder CH. <P>SOLUTION: To index information EXX recorded in a route node RN or cache node CN so as to be referable from the requester RQ, hard disk state information HS showing a hard disk state of each content holder CH is added in addition to a content ID and an IP address of the content holder CH. When the content holder CH as a delivery source is determined in the requester RQ, a content holder CH in a good hard disk state, and easily delivered, is preferentially selected in reference to the hard disk state information HS for delivery. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention belongs to the technical field of a terminal device and its information processing program and information processing method in an information distribution system, and more specifically, formed by participation of a plurality of terminal devices connected to each other via a network. The present invention belongs to a technical field of a terminal device, an information processing program, and an information processing method in an information distribution system that transmits and receives content information such as music content and movie content between the terminal devices.

  In recent years, with the spread of broadband, information distribution services that distribute content information such as music data and movie data have become popular. For example, a service that distributes content information in response to a user request, such as VOD (video on demand), is known.

  This type of information distribution service has been mainly distributed by the server client method, but recently, a P2P (Pear to Pear) type distribution method in which content information is transmitted and received between terminal devices as a new distribution method replacing this method. The form is drawing attention.

  This P2P type information distribution system is formed by participation of a plurality of terminal devices (node devices) connected to each other via a network, and content information to be acquired by a user of a certain terminal device is stored as one of the contents. It is acquired from another terminal device that holds a part or all.

  For example, in the information distribution system described in Patent Document 1, each terminal device does not recognize the location information (such as IP addresses) of all the terminal devices participating in the information distribution system. Only the location information for a part of terminal devices obtained is stored, and based on the location information, the content information is searched and the content information is transmitted and received between the terminal devices.

Here, in the information distribution system described in Patent Document 1, the ease of distribution of content information between terminal devices is determined according to the following requirements (a) to (e).
(A) Range information indicating the range on the network where the terminal device holding the content information exists (b) Maximum transmission speed of the transmission path used for content information distribution (c) Current status of the terminal device holding the content information (D) Frequency at which stoppage of power supply occurs in terminal device holding content information (e) Frequency at which content distribution processing is considered to be stopped in terminal device holding content information

In consideration of such requirements (a) to (e), content information is distributed between the terminal devices, so that it is possible to receive the desired content in the terminal device quickly and efficiently. .
JP 2006-277338 A

  However, in the conventional information distribution system, the distribution of content information has not been sufficiently considered in consideration of the operating state in the terminal device that holds the content information. That is, in the information delivery system in Patent Document 1, the connection environment (above (a), (b)), the number of content delivery (above (c)), the power supply power stop history (above (d)), the delivery process stop history ( The above (e)) is considered, but the operation state in the terminal device that is constantly changing is not sufficiently considered.

  Accordingly, the present invention has been made to solve the above-described problems, and its purpose is to distribute content information between terminal devices in consideration of the operating state in the terminal device holding the content information. Another object of the present invention is to provide a terminal device, an information processing program for the terminal device, and an information processing method that enable the terminal device to receive a desired content quickly and stably.

  In order to solve the above-described problem, the invention according to claim 1 is an information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices. In the terminal device, the content identification information for identifying the content information, the location information of the other terminal device that holds the content information in the hard disk, and the status information of the hard disk of the other terminal device are transmitted via the network. When there is a request for transmitting location information of the other terminal device that holds the content information, an acquisition unit that acquires the storage unit that stores the information acquired by the acquisition unit, and a hard disk of the other terminal device Determination means for determining whether or not the state information satisfies a predetermined condition, and the hard disk state information Is extracted from the storage means and sent to the requesting terminal device, and when the hard disk status information does not satisfy the predetermined condition, the request source Transmission means that does not transmit the location information of the other terminal device to the other terminal device.

  The invention according to claim 2 is the storage means according to the invention according to claim 1, wherein when the updated status information of the hard disk is acquired by the acquisition means, the storage means is obtained according to the acquired status information of the hard disk. Update means for updating the status information of the hard disk stored in the hard disk drive.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the transmission means has a request for transmitting location information of the other terminal device holding the content information. In addition, when there are a plurality of the other terminal devices in which the location information is stored in the storage unit, the location information of the terminal device having a high degree of the condition information of the hard disk satisfying a predetermined condition among these terminal devices. The data is transmitted to the requesting terminal device.

  Further, the invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the status information of the hard disk includes energization accumulated time, temperature, read error occurrence rate, and failure of the hard disk. The information is based on at least one of the number of sectors and the throughput performance.

  Further, in the invention described in claim 5, in the invention described in claim 4, the status information of the hard disk includes the energization accumulation time, temperature, read error occurrence rate, number of defective sectors, and throughput performance of the hard disk. It is score information obtained by scoring at least one of them.

  According to a sixth aspect of the present invention, in the terminal device in the information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices, A hard disk for storing content information, status information acquisition means for acquiring status information of the hard disk from the hard disk, registration information including identification information of content information stored in the hard disk, location information of the own device, and status information of the hard disk Registration message transmission means for transmitting a message to a predetermined terminal device via the network.

  Further, in the invention according to claim 7, in the invention according to claim 6, the status information of the hard disk includes the energization accumulation time, temperature, read error occurrence rate, number of defective sectors, and throughput performance of the hard disk. The information is based on at least one of them.

  Further, in the invention described in claim 8, in the invention described in claim 7, the status information of the hard disk includes current accumulation time, temperature, read error occurrence rate, number of defective sectors, and throughput performance of the hard disk. It is score information obtained by scoring at least one of them.

  The invention according to claim 9 is the invention according to any one of claims 6 to 8, wherein the registration message transmitting means stores the content information in the hard disk or periodically. A registration message is transmitted to another terminal device via the network.

  According to a tenth aspect of the present invention, in the terminal device in the information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices, Information acquisition means for acquiring the location information of a plurality of other terminal devices respectively holding the content information of the other in the hard disk and the status information of the hard disks of the other terminal devices via the network, and the information acquisition means Based on the acquired status information of the hard disk, selection means for selecting one terminal device from among the plurality of other terminal devices from which the location information has been acquired, the desired content information, the selected other information Content acquisition means for acquiring from a terminal device via the network is provided.

  The invention according to claim 11 is the invention according to claim 10, wherein the selection means has predetermined information on the status of the hard disk among the other terminal devices that have acquired location information by the information acquisition means. When there are a plurality of other terminal devices satisfying the above condition, one terminal device is selected at random from those terminal devices.

  According to a twelfth aspect of the present invention, in the invention according to the tenth aspect, the selection unit has predetermined information on the status of the hard disk among the other terminal devices that have acquired location information by the information acquisition unit. When there are a plurality of other terminal devices satisfying the above condition, a terminal device having a high degree of satisfying the predetermined condition is selected from these terminal devices.

  The invention according to claim 13 is the invention according to any one of claims 10 to 12, wherein the status information of the hard disk includes the accumulated energization time of the hard disk, temperature, read error occurrence rate, failure The information is based on at least one of the number of sectors and the throughput performance.

  Further, in the invention described in claim 14, in the invention described in claim 13, the status information of the hard disk includes the energization accumulation time, temperature, read error occurrence rate, number of defective sectors, and throughput performance of the hard disk. It is score information obtained by scoring at least one of them.

  The invention according to claim 15 is an information processing program that causes a computer to function as the terminal device according to any one of claims 1 to 14.

  The invention according to claim 16 is the information processing of the terminal device in an information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices. In the method, acquiring the content identification information for identifying the content information, the location information of the other terminal device holding the content information in the hard disk, and the status information of the hard disk of the other terminal device via the network And storing the acquired information, and when there is a request for transmitting the location information of the other terminal device holding the content information, the hard disk status information of the other terminal device satisfies a predetermined condition. Determining whether or not the hard disk status information satisfies a predetermined condition. Occasionally, characterized by a step of transmitting from said storage means to said another terminal device requesting terminal device retrieves the location information of.

  The invention according to claim 17 is the information processing of the terminal device in an information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices. In the method, the step of storing the content information in a hard disk, the step of acquiring the status information of the hard disk from the hard disk, the identification information of the content information stored in the hard disk, the location information of the own device, and the status information of the hard disk Transmitting a registration message including a message to a predetermined terminal device via the network.

  The invention according to claim 18 is the information processing of the terminal device in an information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices. In the method, the location information of a plurality of other terminal devices each holding desired content information on the hard disk and the hard disk status information of each of the other terminal devices are acquired via the network, and the acquired Based on the status information of the hard disk, the step of selecting one terminal device among the plurality of other terminal devices that have acquired the location information, and the desired content information from the selected other terminal device And obtaining through the network.

  According to the present invention, content information is distributed between the terminal devices in consideration of the state of the hard disk in the terminal device that holds the content information, so that the content information can be distributed quickly and stably.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. The information distribution system described below is formed by participation of a plurality of terminal devices via a network such as the Internet, and transmits / receives content information such as music content and movie content between these terminal devices (in other words, This is an information distribution system that shares content information among a plurality of terminal devices, that is, a so-called P2P type information distribution system. In the following description, the terminal device is referred to as a “node”.

(I) Principle of the Present Invention Before describing the embodiment of the present invention in detail, first, the principle of the present invention will be described with reference to the P2P type information distribution system (hereinafter simply referred to as “information distribution system”) according to the embodiment. It will be explained together with the outline.

(A) Overview of Information Distribution System First, an overview of an information distribution system according to an embodiment will be described with reference to FIGS. 1 and 2. 1 and 2 are schematic diagrams showing an outline of the information distribution system.

  In general, when a specific node connected to the network acquires content information from another node, it is necessary to know information about which node stores which content information. For example, when the network is the Internet, it recognizes a set of index information (for example, a title name of a movie) that can specify content information and an IP (Internet Protocol) address of a node storing the content information, It is necessary to transmit / receive the desired content information using the IP address as a clue. Therefore, in an information distribution system in which an unspecified number of nodes share content information, each node may recognize index information of all content information and the IP address of the node storing it. Necessary.

  However, there is a limit to the physical storage capacity at each node. Therefore, depending on the number of nodes connected to the network, it is practical for each node to store the index information of all content information and the IP address of the node storing the content information. There may not be. For example, when 1 million nodes are connected to the network, it is not realistic for each node to store all 1 million IP addresses and index information.

  Moreover, even when the power switch of each node in the network is frequently turned on / off (for example, when the node is realized by a personal computer, the power switch can be frequently operated), Since the withdrawal and participation of the constituent nodes are frequent, the IP address stored in each node is frequently updated, and the index information of all content information and the IP address of the node in which each content information is stored in each node If it is going to memorize | store, it will become difficult practically as the whole network.

  Therefore, in order to cope with the problems as described above, each node stores an IP address that is the minimum necessary location information of the node, and based on the IP address, the content information is searched to obtain the content information between the nodes. A distribution system having a mechanism for transmitting and receiving data has been studied, and one of them is a distribution system using a so-called DHT (Distributed Hash Table).

  Next, an outline of the distribution system using the DHT will be described.

In the distribution system using the DHT, a node ID (Identification), which is identification information for mutually identifying each node, is assigned to each node. At this time, the node ID is assigned a unique number for each node, that is, a number different from other nodes. This number has a number of bits (bit length) that can accommodate the maximum number of nodes in the network. More specifically, for example, when a 128-bit node ID is used, a maximum of 2 ¹²⁸ = 340 × 10 ³⁶ nodes can be connected in one network. The node ID is generally a hash value for a unique value for each node, such as an IP address assigned to the node itself, a so-called MAC (Media Access Control) address, or a serial number of the node itself. Use the value obtained by applying the function.

  In the information distribution system using the DHT, a content ID that is unique identification information different from other content information is also given to the content information itself distributed in the information distribution system. The bit length of the content ID is also the same as the bit length of the node ID. In general, the content ID includes title data indicating the title of the content information, attribute data indicating attributes of the data constituting the content information, data for several bytes from the head of the data constituting the content information, and the like. On the other hand, a value obtained by applying the same hash function as that for obtaining the node ID is used.

  Here, in relation to the fact that corresponding node IDs and content IDs are expressed with the same bit length, the nodes and content information are scattered in the same ring-shaped virtual ID space. Can be thought of as That is, as shown in FIG. 1A in which one node is displayed with ● and one content information is displayed with ○, the ring Rc to which the content information belongs and the ring Rn to which the node belongs are virtually concentrically formed. Assuming that each ID value increases counterclockwise in each ring Rc and Rn, it can be assumed that each node or each content information exists without overlapping each ring Rc and Rn. If each ID is expressed in 128-bit length as in the above example, the number of digits is too large. In FIG. 1A, for the sake of simplicity of explanation, the bit length of each ID is set to 32 bits. Expressed (the same applies hereinafter). Then, as described above, due to the use of the hash function in determining the value of each ID, each node and each content information should be present in a substantially distributed manner on each of the above rings Rc and Rn. It becomes.

  Here, in an information distribution system using DHT, “a node that manages content information to which a certain content ID is assigned is assigned a node ID having a value closest to the value of the content ID”. It is said that.

  Here, “near” may be any definition as long as it is consistent in various provisions relating to the information distribution system. Specifically, for example, “not exceed the value of the content ID” It is a value that has the smallest difference between values as IDs ”.

  More specifically, for example, as illustrated in FIG. 1A, a node having a node ID value “A0334055” and a node having a node ID value “A03340FF” are adjacent to each other on the ring Rn. If it exists, the content information whose content ID value is “A0334080” is managed by the node whose node ID value is “A0334055”. In FIG. 1A, the terminal information for managing the content information of ○ is indicated by an arrow extending from each ○. In this way, various content information can be managed by being distributed among a large number of nodes.

  At this time, “management” does not mean that the content information to which the content ID is assigned is stored therein, but the IP address that is the location information of the node in which the content information is stored. It means that it is recognized. The node where the content information is actually stored may be different from the managed node, or the managed content information may be stored in the managed node.

  A node that manages content information in this way is referred to as a “root node”. The root node stores index information consisting of a pair of a content ID indicating content information to be managed by the IP address of a node storing the content information indicated by the content ID, This is stored so that it can be referred to from other nodes in the information distribution system. In some cases, the index information includes attribute information such as the title of the content information and its attribute (genre).

  In addition, when content IDs indicating different content information are close to coincidence, and there is no other node having a node ID with a value close to that value, a plurality of root nodes corresponding to a plurality of pieces of content information. The index information is stored. Furthermore, when the same content information is stored in a plurality of different nodes, and the node storing the same content information is close to one root node by chance, The index information of a plurality of nodes each storing the same content information is stored. An example of the index information EX in the root node described above is shown in FIG.

  Further, a node that actually stores each piece of content information itself is referred to as a “content holder”. At this time, since the content holder itself is a node, the node ID exists on the ring Rn in FIG.

  Next, in the information distribution system using the DHT, as described above, the DHT (routing table) itself, which is one of the devices for eliminating the necessity for each node to store the IP addresses of all nodes. explain.

  In the DHT according to the present embodiment, the ID space exemplified in FIG. 1A is subdivided while increasing the number of levels for each stepped level (for example, in the case of level 1, the ID space is divided into four). Then, for each level (each area subdivided in stages), routing information in which a node ID of an arbitrary node and its IP address are paired is described. This DHT is generated by acquiring routing information from a node participating in the information distribution system, such as when the node participates in the information distribution system, and is stored in the storage means of the own node. For example, when the distribution source inquiry information for requesting the distribution information of the content information (such as the location information of the content holder) is transferred to the root node storing the index information, the routing information of the DHT is referred to. The inquiry information is transferred to the target root node. That is, each time the level in DHT increases, the node ID of the routing destination matches the node ID of the root node to be reached one digit at a time, and the request information finally reaches the root node to be reached. Will do.

  In the information distribution system using DHT, the inquiry information (query) as described above, distribution request information for requesting distribution of the content information itself, a registration message described later, and the like are referred to as “message”. . When the DHT having the above-described mechanism is used, the message can be efficiently transferred to the target node in the ID space as illustrated in FIG. In the following description, when content information is newly stored in the content holder, a message generated in the content holder is registered as a registration message so that it can be discovered (published) from other nodes. The above-described distribution source inquiry information, that is, a message transmitted from a requester described later to a root node or a cache node described later is referred to as a search message.

  Here, as described above, since the value of the node ID of the root node is closest to the value of the node ID of the content holder that manages the content information, the search message is the target of the distribution request. The root node that manages the content information is reached. Then, the root node that has received the search message returns the IP address or the like of the content holder that stores the content information requested by the search message to the sender of the search message. That is, from the index information stored in the root node (see FIG. 1B), the title indicating the content information requested by the search message, the attribute information, and the IP address of the node as the content holder Are returned to the node that is the source of the search message. By utilizing such DHT, location information of desired content information can be efficiently recognized, for example, at a distribution request source. The node that is the content information distribution request source described above is hereinafter referred to as a “requester”.

  Next, content information registration processing when new content information is accumulated in a certain node will be described.

  When new content information is stored in a node, that is, the content holder of the content information, the content holder will disclose that the content information has been stored to other nodes in the information distribution system.

  That is, when new content information is stored in a certain node, the node serving as a content holder for the stored content information sets the content ID corresponding to the content information based on the title of the stored content information. calculate.

  Next, the content holder transmits a registration message with a node having a node ID having the same value as the calculated content ID as a destination (regardless of whether or not the node having the node ID actually exists). This registration message includes the title indicating the content information, attribute information, the IP address of the node as the content holder, and the like, and the node as the destination of each level through each routing destination according to the description of the DHT Are sequentially transferred.

  When the node having the closest node ID is reached, the node recognizes that the node to which the registration message is to be transferred thereafter does not exist in the ID space. Recognizing that the node to be transferred is itself), it becomes a root node for managing new content information. Then, the node that has become the root node stores the content ID, the IP address of the content holder, the attribute information, and the like included in the registration message as index information EX illustrated in FIG. 1B.

  Next, the concept of “cache node” in the information distribution system according to the embodiment will be described with reference to FIG. In FIG. 2 and FIG. 3 to be described later, the root node is indicated by a double circle, the content holder is indicated by a circle marked with “X”, and the requester is indicated by a circle marked with “|” inside, which will be described later. A cache node is indicated by a circle with + in the inside, and other general nodes are indicated by a circle.

  When the search message Qr from the requesters RQ1 to RQ3 is transferred to the root node RN (or content holder CH) by the routing using the DHT described above, the transfer route (in FIG. 2A and FIG. 2) is a route similar to the route (shown by a solid line in FIGS. 2A and 2B) followed by the registration message Qp described above, as shown in FIG. If the index information EX illustrated in FIG. 1B is also stored in each node (indicated by reference numeral CN in FIG. 2A), the arrival of the index message EX corresponding to the search message Qr via the route Before the search message Qr reaches the previous root node RN or content holder CH, the response corresponding to the search message Qr is sent to the requester RQ1 at an early stage. It is possible to reply to RQ3.

  That is, the requester RQ1 to RQ3 requesting the distribution of the content information published in the information distribution system requests the search message Qr to request the IP address of the node (that is, the content holder CH) in which the content information is stored. When transmitted, the search message Qr is transferred to the routing destination described in the DHT in each node and approaches the root node RN. Finally, the route merges with the route of the registration message Qp from the content holder CH and reaches the root node RN.

  Here, when the path on the ring Rn shown in FIG. 2A is replaced with a tree structure, the result is as shown in FIG. 2B, which is referred to as “spanning tree” in the embodiment.

  As shown in FIG. 2 (a), the path of the search message Qr transmitted from each requester RQ and the path of the registration message Qp transmitted from the content holder CH eventually intersect at any node on those paths. . Therefore, the index information EX included in the registration message Qp is stored in a temporary storage area that can be temporarily stored in each node on the route for reaching the root registration message Qp to the root node RN ( That is, the registration message Qp is transferred (temporarily cached). Then, a reply to the search message Qr from the requester RQ can be made before the search message Qr reaches the root node RN from the node where the search message Qr on the route to the root node RN has arrived. . Thus, a node other than the root node RN and temporarily storing the index information EX is referred to as a “cache node” CN.

(B) Principle of the present invention Next, the principle of the present invention based on the information distribution system described above will be described with reference to FIG.

  The index information EX in the above-described information distribution system is as illustrated in FIG. 1B, which includes information indicating the content information itself corresponding to each index information EX (for example, FIG. 1B). Other than the title, genre, director name, etc.) shown in FIG. 5), only the corresponding content ID and the IP address of the content holder CH in which the content information is stored, and the status of the hard disk of the corresponding content holder CH Information about was not included.

  Therefore, as shown in FIG. 3, in the present invention, for each of the index information EX, information HS (hereinafter referred to as the hard disk state) of the content holder CH in which the content information corresponding to the index information EX is stored. "Hard disk status information HS") is added respectively. Then, the requester RQ refers to the index information EX, refers to the hard disk state information HS, and connects with priority from the hard disk of the content holder CH, and receives the distribution of the content information. In the following embodiment, the index information according to the present invention to which the hard disk status information HS is added is referred to as index information EXX. In FIG. 3, index information EXX corresponding to a plurality of pieces of content information is stored in a root node RN serving as one information processing apparatus, and a plurality of pieces of content storing the same piece of content information for one piece of content information. The state in which the index information EXX indicating the holder CH is stored is illustrated.

  Here, as parameters included as the contents of the hard disk status information HS, information regarding the hard disk that the content holder CH has in order to hold the content information, that is, the energized cumulative time information 100 of the hard disk, the temperature information 101 of the hard disk Read error rate information 102 in the hard disk, defective sector number information 103 in the hard disk, throughput performance information 104 in the hard disk, energization accumulated time information 100, temperature information 101, and read error rate information 102 described above. In addition, score information 105 indicating the total points of values obtained by scoring the values of the defective sector number information 103 and the throughput performance information 104 by a method described later is included.

  Further, the index information EXX is stored not only in the root node RN shown in FIG. 3 but also in the above-described cache node CN. By referring to this, the request information RQ as request information from the requester RQ is stored. The return information RT corresponding to the search message Qr can be returned to the requester RQ without the search message Qr reaching the root node RN.

  In the case of the information distribution system according to the present invention in which the same content information is stored in a plurality of content holders CH, the reply information RT includes the content information indicating the content information desired to be distributed and the content information. Is included in the index information EXX corresponding to the content holder CH that stores information indicating the number of index information EXX that the requester RQ desires to refer to. Then, in the requester RQ that has received the reply information RT, the content holder CH that is indicated by the index information EXX that the hard disk state is good is selected from the plurality of referenced index information EXX. Connect and receive the content information.

  As described above, the index information EXX including the hard disk state information HS according to the present invention is stored in the root node RN and the cache node CN, respectively, so that the requester RQ refers to these memories and the hard disk state is in a good state. It is possible to receive desired content information from the content holder CH quickly and stably.

(II) Embodiment Next, an embodiment according to the present invention based on the above-described principle will be specifically described with reference to FIGS.

  First, a schematic configuration of a node according to the embodiment will be described with reference to FIG. FIG. 4 is a block diagram illustrating a schematic configuration of the node according to the embodiment. In the present embodiment, the content holder CH, the requester RQ, the root node RN, the cache node CN, and other nodes basically have the same hardware configuration. The outline of the configuration of a general node N will be described with reference to FIG.

  As shown in FIG. 4, the node N according to the embodiment is applicable to a general personal computer in addition to a dedicated computer, a CPU having a calculation function, a working RAM (Random Access Memory), various data, and a program And recording / storing (storing) the content data as the content information itself, the index information EXX, the DHT, and other necessary programs. Hard disk (HDD (Hard Disk Drive): equivalent to an example of storage means) 12, buffer memory 13 for temporarily storing received content data, and encoded video data (encoded) included in the content data ( Video information) and audio data (audio information), etc. (Decoding etc.), a video processing unit 15 that performs a predetermined drawing process on the decoded video data and outputs the video signal, and a video signal output from the video processing unit 15 A display unit 16 composed of a CRT (Cathode Ray Tube) or a liquid crystal display for displaying an image, and the decoded audio data is D / A (Digital / Analog) converted into an analog audio signal and then amplified by an amplifier or the like. A communication unit 20 for performing communication control of information between the audio processing unit 17 to be output, the speaker 18 that outputs the audio signal output from the audio processing unit 17 as a sound wave, and another node device N through the network. And an input unit (for example, a keyboard) that receives an instruction from the user and outputs an instruction signal corresponding to the instruction to the control unit 11. Control unit 11, hard disk 12, buffer memory 13, decoder unit 14, and communication unit 20 can exchange data with each other via bus 22. It is connected to the.

  Then, when the CPU in the control unit 11 executes various programs stored in the internal ROM or the hard disk 12, etc., the control unit 11 performs a requester RQ, a cache node CN, a root node RN, a content holder CH, or other general items. The overall operation of the node N as a whole is controlled.

  When the node N is the content holder CH, the control unit 11 functions as a status information acquisition unit, a registration message transmission unit, and the like. When the node N is the root node RN or the cache node CN, the control unit 11 functions as an acquisition unit, a determination unit, an update unit, a transmission unit, and the like. Further, when the node N is a requester RQ, the control unit 11 functions as an information acquisition unit, a selection unit, a content acquisition unit, and the like.

  Next, the operation of each node N according to the embodiment will be described separately for the content holder CH, the root node RN, the cache node CN, and the requester RQ.

(A) Operation in Content Holder First, the operation in the content holder CH according to the embodiment will be described with reference to FIGS. FIG. 5 is a flowchart showing an example of the operation in the content holder CH according to the embodiment, and FIG. 6 is a diagram showing a specific example of each parameter constituting the hard disk status information HS according to the embodiment.

  In the content holder CH according to the embodiment, first, when new content information for distribution is stored in the hard disk 12 in the content holder CH, the flowchart of FIG. 5 starts. Then, the control unit 11 acquires and generates the hard disk state information HS at the time when the content information is stored in the hard disk 12 (step S2). That is, the control unit 11 requests the hard disk 12 to output each of the energization accumulated time information 100, the temperature information 101, the read error occurrence rate information 102, the defective sector number information 103, and the throughput performance information 104. Get information about. And the control part 11 produces | generates the score information 105 which scored these information and totaled. As described above, the control unit 11 functions as a state information acquisition unit that acquires the hard disk state information HS from the hard disk 12.

  The control unit 11 transmits the registration message Qp (see FIG. 3) including the index information EXX having the hard disk status information HS acquired and generated in this way to the node N that should be the root node RN via the communication unit 20. (Step S3). Thus, when the content information is newly stored in the hard disk 12, the control unit 11 sends a registration message including the content ID of the content information stored in the hard disk 12, the IP address of the local node, and the hard disk status information HS of the local node to the network. Functions as a registration message transmission means for transmitting to the root node RN (the root node RN of the content information stored in the hard disk 12).

  Here, each parameter (energization accumulated time information 100, temperature information 101, read error occurrence rate information 102, defective sector number information 103, and throughput performance information 104, which constitute the hard disk status information HS according to the embodiment, see FIG. 3). This will be specifically described with reference to FIG.

  Each parameter constituting the hard disk status information HS is acquired from the hard disk 12 by the control unit 11. That is, the hard disk 12 has a well-known Self-Monitoring, Analysis and Reporting Technology (self-monitoring, analysis and reporting technology, commonly referred to as “SMART”) function. Uses the SMART function of the hard disk 12 to obtain the hard disk status information HS. This SMART (smart) is a function that is installed in hard disk drives for the purpose of early detection of hard disk drive failures and prediction of failures, and self-diagnose various inspection items in real time, and quantifies their status, It is output in response to an external request.

  In the node N of this embodiment, by using the SMART (smart) function mounted on the hard disk 12, various SMART information (energization accumulated time information 100, temperature information 101, read error occurrence rate information 102, number of defective sectors). The control unit 11 reads out and acquires the information 103 and the throughput performance information 104 from the hard disk 12, but the hard disk 12 may incorporate a function similar to the SMART (smart) function.

  The energization accumulated time information 100 is information of SMART information ID = 09 (Power-On Hours), and is information on the total energization time of the hard disk 12 from the factory shipment state. When SMART information is not used, the control unit 11 may count the energization time of the hard disk 12. For example, a switch that controls power supply to the hard disk 12 is provided, and the control unit 11 controls the switch to count the total time during which the hard disk 12 is energized.

  The temperature information 101 is SMART information ID = C2 (194) (Temperature) information and is the current temperature of the hard disk 12. The guaranteed temperature of the hard disk 12 in the present embodiment is 55 ° C. (similar guaranteed temperature for general hard disks), so the score is set higher as the temperature is lower. When SMART information is not used, a temperature sensor may be provided on the surface of the hard disk 12 and the temperature detected by this temperature sensor may be used as the temperature information 101.

  The read error occurrence rate information 102 is information of SMART information ID = 01 (Raw Read Error Rate), and is information on the rate of errors (read error occurrence rate) that occurred when reading data from the hard disk 12. In the present embodiment, the score is set higher as the ratio of the read error occurrence rate to the predetermined threshold (allowable value) of the read error occurrence rate is lower.

  The defective sector number information 103 is information of SMART information ID = 05 (Reallocated Sectors Count), and is information on the number of defective sectors that have been subjected to substitution processing (that is, data has been moved to the substitution sector). In the present embodiment, the score is set higher as the ratio of the number of defective sectors to the predetermined threshold (allowable value) of the number of defective sectors is lower.

  The throughput performance information 104 is information of SMART information ID = 02 (Throughput Performance), and is information on whether or not a specified performance has been achieved (information on the processing capacity of the hard disk 12). In the present embodiment, the lower the ratio of the throughput performance to the predetermined threshold (allowable value) of the throughput performance, the higher the probability that the hard disk 12 is abnormal. In other words, the higher the throughput performance, the higher the score.

  Finally, the score information 105 is obtained by summing the scores of the energized cumulative time information 100, the temperature information 101, the read error occurrence rate information 102, the defective sector number information 103, and the throughput performance information 104 described above. As the score information 105, a score obtained by simply adding the scores of the energization accumulated time information 100 or the like may be used as the score information 105, or each parameter such as the energization accumulated time information 100 may be set in advance. It is good also as a value as the score information 105 that is added after weighting, and normalized so that the maximum score as the score information 105 is, for example, 100 points. As an example of the weighting at this time, as shown in FIG. 6, for example, the weighting of the energization accumulated time information 100 is 40/100, the temperature information 101 is 30/100, the temperature information 101, and the read error occurrence rate. The weighting of the information 102, the defective sector number information 103, and the throughput performance information 104 is 10/100, respectively.

  As described above, when the registration message Qp including the index information EXX to which the hard disk status information HS including the parameters illustrated in FIGS. 3 and 6 is added is transmitted toward the node N that should be the root node RN. (Step S3), the control unit 11 starts timing in a timer (not shown) in the control unit 11 of the content holder CH that has transmitted the registration message Qp (step S4).

  Next, the control unit 11 determines whether or not a predetermined time T1 has elapsed since the start of the time measurement in the immediately preceding step S4 (step S5). When 15 minutes have elapsed (step S5: Yes), the control unit 11 assumes that the hard disk state information HS corresponding to the content holder CH in the root node RN should be updated, as in step S2. The state information HS is acquired / generated. Then, the registration message Qp including the hard disk state information HS generated in this way is transmitted as a registration message Qp for updating toward the root node RN via the communication unit 20 (step S6). In this way, the control unit 11 functions as a registration message transmission unit that periodically transmits the registration message Qp to the root node RN via the communication unit 20.

  Next, the control unit 11 determines whether or not the content information stored in the content holder CH has been erased from the hard disk 12 (step S7). When it is erased (step S7: Yes), the control unit 11 completes the processing as the embodiment in the content holder CH, while when it is not erased yet (step S7: No), the hard disk After updating the state information HS (step S6), the process returns to step S4 so as to start timing in a new timer.

  By the operation as the content holder CH described above, new generation and update of the hard disk status information HS accompanying the initial registration of the content information is executed, and the index information EXX including it is stored in the root node RN (and the cache node CN). Remembered.

  In the above description, the information update message is transmitted every predetermined period T1. In addition, any parameter (for example, the most likely change is the hard disk status information HS in the content holder CH). When it is determined whether the content of the temperature information 101) that is expected to be high has changed by a predetermined threshold (for example, ± 10%) or more, the control unit 11 stores the content holder CH in the root node RN. The corresponding hard disk status information HS should be updated, and a registration message Qp for the update may be transmitted to the root node RN via the communication unit 20.

(B) Operations in Root Node and Cache Node Next, operations in the root node RN and the cache node CN according to the embodiment will be described with reference to FIGS. FIG. 7 is a flowchart showing an example of the operation at the time of message reception in the root node RN and the cache node CN according to the embodiment, and FIGS. 8 and 9 show an example of the detailed operation in the root node RN and the cache node CN. It is a flowchart shown respectively.

  In the root node RN and the cache node CN according to the embodiment, the control unit 11 sends some message (either the registration message Qp or the search message Qr) from any of the nodes N in the information distribution system via the communication unit 20. 7 is started, the flowchart of FIG. 7 is started. Then, the control unit 11 determines whether the message is the registration message Qp from the content holder CH or the search message Qr from the requester RQ based on the information of the header portion of the message (step S11). .

  When the received message is the search message Qr from the requester RQ (step S11: from the requester), the control unit 11 is the root node RN of the content information requested by the search message. It is determined whether the node is a cache node CN (step S12).

  In this process, when the own node is the root node RN (step S12: root node), the control unit 11 returns a response process (return information RT of the reply information RT) to the search message Qr as the root node RN via the communication unit 20. Transmission) (step S13), and the operation as the root node RN ends. Details of the operation in step S13 will be described later.

  On the other hand, when it is determined in step S12 that the own node is the cache node CN (step S12: cache node), the control unit 11 performs a reply process to the search message Qr as the cache node CN (step S14). The operation as the cache node CN ends. Details of the operation in step S14 will be described later in detail.

  On the other hand, when the received message is the registration message Qp from the content holder CH in the determination in step S11 (step S11: from the content holder), the control unit 11 determines its own node as in the determination in step S12. Is the root node RN of the content information requested by the registration message Qp or the cache node CN (step S15). As described above, the control unit 11 receives the registration message Qp including the content ID for identifying the content information, the IP address of the content holder CH that holds the content information in the hard disk 12, and the hard disk status information HS of the content holder CH. It functions as an acquisition means for acquiring via a network.

  In this process, when the node N is the root node RN (step S15: root node), the control unit 11 further transmits the received registration message Qp from the content holder CH when content information is newly registered. Whether it is Qp or the registration message Qp for updating the index information EXX corresponding to the registered content information is determined based on the contents thereof (step S16). When the received registration message Qp is a registration message Qp for new registration (step S16: registration), the control unit 11 performs a registration process using the registration message Qp as the root node RN (step S17). ), The operation as the root node RN ends. Details of the operation in step S17 will be described later in detail.

  On the other hand, if it is determined in step S16 that the received registration message Qp is an update registration message Qp (step S16: update), the control unit 11 performs an update process using the registration message Qp as the root node RN. (Step S18), and the operation as the root node RN ends. Details of the operation in step S18 will be described later in detail.

  On the other hand, if it is determined in step S15 that the node N is the cache node CN (step S15: cache node), the control unit 11 further uses the received registration message Qp for new registration as in step S16. Whether it is the registration message Qp or the registration message Qp for updating the index information EXX is determined based on the contents thereof (step S19). When the received registration message Qp is a registration message Qp for new registration (step S19: registration), the control unit 11 performs a registration process using the registration message Qp as the cache node CN (step S20). ), The operation as the cache node CN is terminated. Details of the operation in step S20 will be described later in detail.

  On the other hand, if it is determined in step S19 that the received registration message Qp is an update registration message Qp (step S19: update), the control unit 11 performs an update process using the registration message Qp as the cache node CN. (Step S21), and the operation as the cache node CN is terminated. Details of the operation in step S21 will be described later.

  Next, details of the reply process to the search message Qr in the cache node CN as step S14 will be described with reference to FIG.

  When the search message Qr is received at the cache node CN (see FIG. 3) that stores the index information EXX similar to that of the root node RN, as shown in FIG. Then, the index information EXX including the content information desired in the requester RQ that transmitted it and the number of the index information EXX are extracted (step S30). Then, the control unit 11 determines whether or not the index information EXX having the same identification information as the identification information for identifying the index information EXX extracted from the search message Qr is actually stored in the own node (Step S11). S31). At this time, if the index information EXX corresponding to the desired content information is not in the cache node CN (step S31: No), the control unit 11 is necessary in the other root node RN or the cache node CN. In order to search the correct index information EXX, the search message Qr is transferred via the communication unit 20 with reference to DHT (step S34), and the processing as the cache node CN according to the embodiment is ended.

  On the other hand, when the index information EXX corresponding to the desired content information in the search message Qr is found in the cache node CN in the determination in step S31 (step S31: Yes), the control unit 11 The score information 105 included in the found index information EXX is extracted (step S32).

  And the control part 11 is a threshold value (the score of the score information 105 that should be included in the index information EXX desired in the requester RQ by the search message Qr and the value of the score information 105 extracted for each index information EXX. And whether or not there is a desired number of index information EXX including the score information 105 having a score equal to or higher than the threshold value, as indicated by the search message Qr. Judgment is made (step S33). As described above, when there is a transmission request for information (IP address of the content holder CH) included in the index information EXX held by the own node, the control unit 11 determines that the hard disk status information HS of the content holder CH satisfies a predetermined condition. It functions as a determination means for determining whether or not the condition is satisfied.

  In this process, when the desired number of index information EXX including the score information 105 having a score equal to or higher than the threshold value does not exist in the cache node CN (step S33: No), the control unit 11 communicates the search message Qr. The data is transferred via the unit 20 (step S34), and the processing as the cache node CN according to the embodiment is terminated.

  On the other hand, in the determination in step S33, when the desired number of index information EXX including the score information 105 having a score equal to or higher than the threshold is present in the cache node CN (step S33: Yes), the control unit 11 The desired number of index information EXX is returned to the requester RQ that has transmitted the search message Qr via the communication unit 20 (step S35), and the processing as the cache node CN according to the embodiment is terminated.

  As described above, when the hard disk state information HS satisfies the predetermined condition, the control unit 11 extracts the IP address that is the location information of the content holder CH from the hard disk 12 and transmits the IP address to the requester RQ. Functions as a transmission means for transferring the search message Qr to another cache node CN or root node RN.

  Next, details of a reply process to the search message Qr in the root node RN as the step S13 will be described with reference to FIG.

  When the search message Qr is received at the root node RN, as shown in FIG. 8B, the control unit 11 performs the index information EXX corresponding to the search message Qr and the index information as in the process of step S30. The number of EXX is extracted (step S40), and then the point information 105 included in the index information EXX is extracted (step S41), as in the process of step S32.

  Then, the control unit 11 compares the value of the score information 105 of each index information EXX with the threshold value as in the process of step S33, and the index information EXX including the score information 105 having a score equal to or higher than the threshold value is obtained. It is determined whether there is a desired number indicated by the search message Qr (step S42).

  In this process, when the desired number of index information EXX including the score information 105 having a score equal to or higher than the threshold value does not exist in the root node RN (step S42: No), the index information EXX equal to or higher than the threshold value requested in the search message Qr Since the index information EXX including the value score information 105 cannot be found in the desired number, it is returned to the requester RQ that transmitted the search message Qr via the communication unit 20 to the effect that it should wait for a while (step S44). The process as the root node RN according to the form is terminated.

  On the other hand, in the determination in step S42, when the desired number of index information EXX including the score information 105 having a score equal to or higher than the threshold value exists in the root node RN (step S42: Yes), the control unit 11 The desired number of index information EXX is returned to the requester RQ that transmitted the search message Qr via the communication unit 20 (step S43), and the process as the root node RN according to the embodiment is terminated.

  As described above, when the hard disk state information HS satisfies the predetermined condition, the control unit 11 extracts the IP address of the content holder CH from the hard disk 12 and transmits it to the requester RQ, and the hard disk state information HS does not satisfy the predetermined condition. At this time, it functions as a transmission means that does not transmit the IP address that is the location information of the content holder CH to the requester RQ.

  Here, in the determination of step S42, when the index information EXX including the score information 105 having a score equal to or greater than the threshold exceeds the desired number and exists in the root node RN (step S42: Yes), the control unit 11 Selects the desired number of index information EXX from the index information EXX having the hard disk status information HS having a large score difference from the threshold, and searches the desired number of index information EXX via the communication unit 20. You may make it reply with respect to requester RQ which transmitted message Qr. By doing so, the requester RQ can acquire the content information from the content holder CH in a state where the hard disk 12 is good, and can acquire the content information more stably. As described above, when the control unit 11 receives the search message Qr that is a transmission request for the IP address that is the location information of the content holder CH that holds the content information, the content holder CH whose IP address is stored in the hard disk 12 is received. Among these content holders CH, the IP address which is the location information of a node (here, a node having a large difference from the threshold) whose hard disk state information HS satisfies a predetermined condition is sent to the requester RQ. It functions as a transmission means for transmitting.

  Next, details of the processing corresponding to the registration message Qp for new registration in the root node RN as step S17 will be described with reference to FIG.

  As shown in FIG. 9A, when the registration message Qp for new registration is received at the root node RN (step S50), the control unit 11 sends the index information EXX together with the hard disk status information HS included therein to the own node. The information is stored and registered in the hard disk 12 (step S51), and the process as the root node RN according to the embodiment is terminated.

  Next, details of the processing corresponding to the update registration message Qp in the root node RN in step S18 will be described with reference to FIG.

  As shown in FIG. 9B, when the root node RN receives the registration message Qp for updating the hard disk status information HS (step S55), the control unit 11 stores the same content information and content holder CH as the index information EXX. The existing index information EXX having the IP address is searched in the root node RN (step S56), and the contents of the searched index information EXX are rewritten with the contents of the new index information EXX included in the update registration message Qp. (Step S57), the process as the root node RN according to the embodiment is terminated.

  Next, details of the processing corresponding to the registration message Qp for new registration in the cache node CN as step S20 will be described with reference to FIG.

  As shown in FIG. 9C, when the registration message Qp for new registration is received in the cache node CN (step S60), the control unit 11 includes the hard disk 12 along with the hard disk status information HS included in the index information EXX. Is stored and registered (step S61), and the registration message Qp for new registration is further transferred to the next cache node CN via the communication unit 20 (step S62), as the cache node CN according to the embodiment. End the process.

  Finally, details of the processing corresponding to the update registration message Qp in the cache node CN as step S21 will be described with reference to FIG.

  As shown in FIG. 9 (d), when the cache node CN receives the registration message Qp for updating the hard disk state information HS (step S65), the control unit 11 stores the same content information and content holder CH as the index information EXX. The existing index information EXX having the IP address is searched in the cache node CN (step S66), and the contents of the searched index information EXX are rewritten with the contents of the new index information EXX included in the update registration message Qp ( In step S67), the registration message Qp for update is further transferred to the next cache node CN via the communication unit 20 (step S68), and the process as the cache node CN according to the embodiment is terminated. As described above, when the updated hard disk status information HS (information included in the update registration message Qp) is acquired via the communication unit 20, the control unit 11 uses the acquired hard disk status information HS according to the acquired hard disk status information HS. It functions as an updating means for updating the hard disk status information HS stored in.

(C) Operation in Requester Finally, the operation in the requester RQ according to the embodiment will be described with reference to FIG. FIG. 10 is a flowchart showing an example of the operation in the requester RQ according to the embodiment.

  In the requester RQ according to the embodiment, an operation (for example, specified by the user from a list of content information that can be transmitted and received by the information distribution system) requested by the user to request distribution of desired content information is input in the requester RQ. When executed in the unit 21, the flowchart of FIG. 10 starts. Then, the control unit 11 calculates a content ID indicating the content information requested to be distributed (for example, calculates a content ID by calculating a part of attribute information of the content information from a list of content information using a hash function). (Step S71), and further, the threshold value to be included in the search message Qr is specifically determined by the number of index information EXX requesting reference (= the number of content holders CH to be the distribution source of the content information). To decide.

  Here, regarding the relationship between the number of reference requests for the index information EXX and the threshold value, specifically, for example, when the number of reference requests is only one, the distribution of the hard disk 12 is more improved in order to improve redundancy. Since it is necessary to select a content holder CH having a good state, when the threshold is set to “90 points” and the number of reference requests is two or three, the state of the hard disk 12 is somewhat poor for one content holder CH. Therefore, when the threshold value is “80 points” and the number of reference requests is 4 or 5, the state of the hard disk 12 for one content holder CH may be further deteriorated, so the threshold value is “70 points”. When the number of reference requests is 6 to 9, the state of the hard disk 12 for one content holder CH may be worse. And "60 points" a threshold for similarly when the number of the reference request is 10 or more may be a threshold value as "40 points".

  When the threshold value as the search message Qr is determined, the control unit 11 then transmits the search message toward the root node RN on the spanning tree in the network in the information distribution system according to the embodiment via the communication unit 20. Qr is transmitted (step S72), and the desired index information EXX can be acquired as a transmission result via the communication unit 20 (see step S35 in FIG. 8A or step S43 in FIG. 8B) or wait for a while. It is determined whether a message indicating that it should be sent has been sent (see step S44 in FIG. 8B) (step S73).

  In this process, if a message indicating that the search message Qr should wait for a while is sent (step S73: Please wait), new index information EXX can be obtained after a certain amount of time has passed. Therefore, it is confirmed whether or not the search message Qr is transmitted again (step S74). When the search message Qr is transmitted again (step S74: Yes), after waiting for a preset standby time (for example, 15 minutes) to pass (step S75), the process proceeds to step S72 and the previous time. The search message Qr having the same content as is transmitted to the root node RN on the spanning tree according to the embodiment via the communication unit 20. On the other hand, if it is determined in step S74 that the search message Qr is not retransmitted automatically (that is, retransmitted by the operation of the user who uses the requester RQ) (step S74: No), it is performed as it is. The processing as the requester RQ according to the embodiment is completed.

  On the other hand, in step S73, when the desired number of index information EXX having a value of the score information 105 higher than the threshold included in the search message Qr is obtained from the root node RN for the search message Qr (step S73). : The index information reception), the control unit 11 searches the index information EXX having the highest value of the score information 105 from the obtained index information EXX, and sets the content holder CH indicated by the index information EXX of the content information. It determines as content holder CH which requests | requires transmission (step S76). In this way, the control unit 11 acquires the IP address, which is the location information of the plurality of content holders CH that respectively hold the desired content information in the hard disk 12, and the hard disk status information HS of the content holder CH via the network. It functions as an information acquisition unit, and further functions as a selection unit that selects one content holder CH among a plurality of content holders CH from which location information has been acquired based on the hard disk status information HS acquired by the information acquisition unit.

  Thereafter, the control unit 11 connects to the content holder CH selected in step S76, downloads the desired content information from the content holder CH (step S77), and completes the processing as the requester RQ according to the embodiment. . Thus, the control unit 11 functions as a content acquisition unit that acquires desired content information from another selected node via the network.

  As described above, according to the operations of the content holder CH, the root node RN, the cache node CN, and the requester RQ as the node N according to the embodiment, the index information EXX including the hard disk status information HS is stored in the information distribution system. Since it is stored in the root node RN and the cache node CN so that it can be referred to from the requester RQ via the network, it is possible to select a content holder CH as a content information distribution source based on the hard disk status information HS in the requester RQ. It is possible to receive content information quickly and stably.

  Accordingly, even when there is a difference in the hard disk status information HS between the content holders CH, the content information can be distributed quickly and efficiently by selecting the content holder CH having a good hard disk 12 status in the requester RQ.

  Further, when the hard disk status information HS in the content holder CH is updated, the index information EXX stored in the root node RN and the cache node CN is updated with the index information EXX including the updated hard disk status information HS. The latest hard disk status information HS can always be referred to from the requester RQ that receives the distribution of the content information.

  Furthermore, the requester RQ that receives the distribution of the content information can acquire the index information EXX itself including the hard disk status information HS and use it for selecting the content holder CH as the distribution source.

  Furthermore, since the hard disk status information HS includes the energization accumulated time information 100, the temperature information 101, the read error occurrence rate information 102, the defective sector number information 103, and the throughput performance information 104 as parameters, the content information is distributed. In the requester RQ, it is possible to accurately grasp the hard disk state of the content holder CH and select the content holder CH with the best hard disk 12 state.

  Further, since the hard disk status information HS includes the accumulated current time information 100, the temperature information 101, the read error occurrence rate information 102, the defective sector number information 103, and the throughput performance information 104, the score information 105 is obtained by scoring. By referring to this, the requester RQ can determine the state of the hard disk 12 as an objective numerical value and select the content holder CH having the best state of the hard disk 12. It is also possible to include information obtained by scoring each of energization accumulated time information 100, temperature information 101, read error occurrence rate information 102, defective sector number information 103, and throughput performance information 104.

  By the way, as described above, since the content holder CH having a good state of the hard disk 12 is selected in the requester RQ, the root node RN and the cache node CN select the index information EXX based on the hard disk state information HS. You can also avoid it. That is, when the process of step 32 is completed without performing the process of step S33 in FIG. 8A, the process of step S35 is performed, and the process of step S41 in FIG. When the number of pieces of index information EXX is selected, the process of step S43 is performed, and when there is no desired number, the process of step S44 is performed.

  In this case, the operation in the requester RQ can be, for example, an operation as shown in the flowchart of FIG. The processes in steps S80 to S85 in this flowchart are the same as steps S70 to S75 in FIG.

As shown in FIG. 11, in step S83, for the search message Qr, the index information EXX having a value of the score information 105 higher than the threshold value included in the search message Qr is received from the root node RN or the cache node CN. In the case where only the index information is obtained (step S83: reception of index information), the control unit 11 compares the value of the score information 105 of each index information EXX with a threshold value, and includes an index including the score information 105 having a score equal to or higher than the threshold value. It is determined whether there is information EXX (step S86). In this process, when the index information EXX including the score information 105 having a score equal to or higher than the threshold value does not exist in the cache node CN (step S86: No), the control unit 11 instructs the information distribution apparatus (not shown). The transmission of desired content information is requested via the communication unit 20, and the content information is acquired from the information distribution device via the communication unit 20. On the other hand, when the index information EXX including the score information 105 having a score equal to or higher than the threshold is present in the root node RN in the determination in step S86 (step S86: Yes), the control unit 11
A content holder that searches the index information EXX of the score information 105 having the highest difference from the threshold from the obtained index information EXX, and requests the content holder CH indicated by the index information EXX to transmit the content information Select as CH (step S87). As described above, when there are a plurality of content holders CH whose state information of the hard disk 12 satisfies the predetermined condition among the content holders CH whose IP address has been acquired by the information acquisition unit, the control unit 11 randomly selects among those nodes. It functions as a selection means for selecting one content holder CH. And the control part 11 requests | requires acquisition of desired content information from the content holder CH selected in this way via the communication part 20, and downloads the said content information via the communication part 20 (step S88).

  In step S87, the control unit 11 does not search the index information EXX having the highest difference from the threshold value from the index information EXX, but instead the index information EXX in the acquired index information EXX. You may make it select EXX. As described above, when there are a plurality of content holders CH whose state information of the hard disk 12 satisfies the predetermined condition among the content holders CH that have acquired the IP address as the location information, the control unit 11 selects the content holders CH from the content holders CH. You may make it function as a selection means to select the content holder CH with a high degree which satisfy | fills the said predetermined condition.

  Furthermore, in the above-described embodiment, since the index information EXX is selected by the requester RQ with reference to a preset threshold, distribution is easy without complicated determination processing in the requester RQ that receives distribution of content information. The content holder CH can be easily selected.

  Furthermore, since the threshold value is changed according to the number of content holders CH that it is desired to distribute content information, for example, content that can be easily distributed even when one content information is distributed from a plurality of content holders CH. It is possible to appropriately determine a plurality of holders CH and receive the distribution.

  Further, the hard disk status information HS is updated at a preset time T1 (15 minutes in the embodiment) in the content holder CH, and the newly generated hard disk status information HS is updated at the root node RN (and Therefore, the requester RQ can refer to the latest hard disk status information HS for each piece of content information.

  In the information distribution system in the above-described embodiment, the hard disk status information HS is updated at a preset time, for example, every 15 minutes as described above, but in addition to this, the hard disc status information HS is updated at a preset time. You may make it update.

  Further, in the requester RQ, when the connection state with the content holder CH that is currently connected and receiving the distribution of content information becomes unstable, the index including the hard disk state information HS with a good hard disk state at the next point Reconnecting to the content holder CH indicated by the information EXX and receiving the distribution of the content information, the distribution of the same content information can be continuously received even if the network becomes partially unstable.

  Although the requester RQ includes a threshold value in the search message Qr, the threshold value may be set in advance in the root node RN and the threshold value may be compared with the score information of the hard disk status information HS.

  In the above-described embodiment, the energization accumulated time information 100, the temperature information 101, the read error occurrence rate information 102, the defective sector number information 103, and the throughput performance information 104 are listed as parameters constituting the hard disk status information HS. If any one of the above parameters is included as the hard disk status information HS, the effects of the present invention can be achieved.

  For example, you may comprise only energization accumulation time information 100 as a parameter of hard disk status information HS. The energization accumulated time information 100 plays an important role in determining the life of the hard disk 12. Accordingly, the control unit 11 of the root node RN notifies the requester RQ of the index information EXX of the content holder CH that has exceeded the guaranteed energization time of the hard disk 12 among the index information EXX stored in the hard disk 12 of its own node. By not doing so, the content holder CH breaks down or the operation becomes unstable while acquiring the content information, and as a result, the content information cannot be acquired and it takes time to acquire the content information. Such a problem can be avoided.

  Further, only the temperature information 101 may be configured as a parameter of the hard disk status information HS. The temperature information 101 plays an important role in grasping a high temperature state that causes a failure in the hard disk 12. A typical hard disk has a maximum operation guarantee temperature of 55 ° C. Therefore, the control unit 11 of the root node RN includes the index information EXX stored in the hard disk 12 of the local node RN of the content holder CH whose temperature of the hard disk 12 exceeds the maximum guaranteed operating temperature (or a temperature close thereto). By not sending the index information EXX to the requester RQ, there is a problem or content that the content holder CH fails or becomes unstable during the acquisition of the content information, and as a result, the content information cannot be acquired. It is possible to avoid the problem of taking information acquisition time.

  Further, the hard disk status information HS may be configured with only one of the read error occurrence rate information 102, the defective sector number information 103, and the throughput performance information 104 as a parameter. These play an important role in grasping the abnormal state of the hard disk 12. For example, if the throughput performance is low, the probability that there is an abnormality in the hard disk 12 increases. Further, if the read error occurrence rate is high, the probability that the hard disk 12 is abnormal is increased. Therefore, the control unit 11 of the root node RN, among the index information EXX stored in the hard disk 12 of its own node, the index information EXX of the content holder CH that is estimated to have a high probability of being abnormal based on such information. Is not notified to the requester RQ, the content holder CH is broken or the operation becomes unstable while acquiring the content information, and as a result, the content information cannot be acquired or the content information is acquired. The problem of taking time can be avoided.

  In the above-described embodiment, when a certain amount of deviation occurs in the reception interval of the unit data constituting the content data, it is determined that the connection with the content holder CH connected at that time has become unstable. In addition to this, the content holder CH to be distributed can be switched. Alternatively, the content holder CH may be switched in the same manner when the connection is completely disconnected.

  Even in this case, even if the connection with the previous content holder CH is disconnected, the same content information can be continuously distributed.

  Further, in the above-described embodiment, among the parameters constituting the hard disk status information HS, the energization accumulated time information 100, the temperature information 101, the read error occurrence rate information 102, the defective sector number information 103, and the throughput performance information 104 are scored. Although the content holder CH has performed, the hard disk status information HS can be scored at any of the requester RQ, the root node RN, and the cache node CN.

  Note that if the entire hard disk status information HS is transmitted to the requester RQ, the amount of data exchanged in the requester RQ increases. Therefore, only the score information 105 after scoring can be transmitted to the requester RQ. .

  In the above-described embodiment, scoring in the hard disk status information HS is performed by defining that the hard disk 12 is in a better state as the score is higher. On the contrary, as the score is lower, the score is lower. The scoring may be performed by defining that the state of the hard disk 12 is good, and the scoring may be performed using any scoring method as long as it is uniformly defined in the information distribution system. good.

  Furthermore, the program corresponding to the flowcharts shown in FIG. 5 and FIGS. 7 to 10 described above is recorded on an information recording medium such as an optical disk such as a CD or DVD, or obtained via the Internet or the like to obtain the hard disk 12 or the like. It is also possible to cause the computer to function as the control unit 11 according to the embodiment by storing them in a computer and reading and executing them with a general-purpose computer.

  In addition to hard disk status information HS, range information (AS (Autonomous System) number of ISP (Internet Service Provider) to which content holder CH belongs) and line type information (used when connecting content holder CH to the network). Type (analog line, optical line, ADSL, CATV line)), congestion level information (ratio of the number of simultaneous simultaneous distributions to the maximum number of simultaneous distribution of content holder CH in the line type), frequency In consideration of information (past frequency of stopping the supply of power in the content holder CH, past frequency of forcibly terminating the distribution process due to timeout), etc. (for example, in addition to the score of the hard disk status information HS, Content obtained between the nodes N) (the total obtained by scoring these pieces of information as score information 105) It may be carried out the delivery of the broadcast.

It is a schematic diagram (I) which shows the outline | summary of the information delivery system which concerns on embodiment, (a) is a schematic diagram which shows ID space in the said information delivery system, (b) is a figure which illustrates index information. It is a schematic diagram (II) which shows the outline | summary of the information delivery system which concerns on embodiment, (a) is a schematic diagram which shows the transmission state of the message in the said information delivery system, (b) is the said message represented as spanning tree It is a figure which shows the transmission state of. It is a figure which shows the principle of this invention. It is a block diagram which shows the outline structure of the node which concerns on embodiment common about a content holder etc. It is a flowchart which shows the operation | movement in the content holder which concerns on embodiment. It is a figure which shows the specific example of each parameter which comprises the hard disk status information which concerns on embodiment. It is a flowchart which shows the whole operation | movement in the root node and cache node which concern on embodiment. 5 is a flowchart (I) showing detailed operations in the root node and the cache node according to the embodiment, (a) is a flowchart showing an operation corresponding to a search message in the cache node, and (b) is a search message in the root node. It is a flowchart which shows a corresponding operation | movement. It is flowchart (II) which shows the whole operation | movement in the root node which concerns on embodiment, and a cache node, (a) And (b) is a flowchart which shows the operation | movement corresponding to the registration message in a root node, (c) and (d ) Is a flowchart showing the operation corresponding to the registration message in the cache node. It is a flowchart which shows the operation | movement in the requester which concerns on embodiment. It is a flowchart which shows the other operation | movement in the requester which concerns on embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Control part 12 Hard disk 13 Buffer memory 14 Decoder part 15 Image | video processing part 16 Display part 17 Audio | voice processing part 18 Speaker 20 Communication part 20
21 Input unit 22 Bus 100 Current accumulation time information 101 Temperature information 102 Read error occurrence rate information 103 Bad sector number information 104 Throughput performance information 105 Point information Rc, RN Ring EX, EXX Index information CH Content holder RQ, RQ1, RQ2, RQ3 Requester RN Root node CN Cache node Qp Registration message Qr Search message N node HS Hard disk status information RT Reply information

Claims (18)

In the terminal device in the information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices,
Acquisition means for acquiring content identification information for identifying content information, location information of another terminal device holding the content information in the hard disk, and status information of the hard disk of the other terminal device via the network;
Storage means for storing information acquired by the acquisition means;
Determining means for determining whether or not the status information of the hard disk of the other terminal device satisfies a predetermined condition when there is a transmission request for the location information of the other terminal device holding the content information;
When the hard disk status information satisfies a predetermined condition, the location information of the other terminal device is extracted from the storage means and transmitted to the requesting terminal device, and the hard disk status information does not satisfy the predetermined condition. And a transmitting unit that does not transmit the location information of the other terminal device to the requesting terminal device. When the updated status information of the hard disk is acquired by the acquiring means, the hard disk status information stored in the storage means is updated with the acquired status information of the hard disk. The terminal device according to claim 1. The transmission means includes
When there is a request for transmission of location information of the other terminal device holding the content information, and there are a plurality of other terminal devices in which the location information is stored in the storage means, among these terminal devices The terminal device according to claim 1, wherein location information of a terminal device whose state information of the hard disk has a high degree of satisfying a predetermined condition is transmitted to the requesting terminal device. The hard disk status information is information based on at least one of the cumulative energization time, temperature, read error occurrence rate, number of defective sectors, and throughput performance of the hard disk. The terminal device according to any one of 3. The hard disk status information is score information obtained by scoring at least one of the cumulative energization time, temperature, read error occurrence rate, number of defective sectors, and throughput performance of the hard disk. Item 5. The terminal device according to Item 4. In the terminal device in the information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices,
A hard disk for storing the content information;
Status information acquisition means for acquiring status information of the hard disk from the hard disk;
Registration message transmitting means for transmitting a registration message including identification information of content information stored in the hard disk, location information of the own device, and status information of the hard disk to a predetermined terminal device via the network. Characteristic terminal device. The hard disk status information is information based on at least one of an energization cumulative time, temperature, read error occurrence rate, number of defective sectors, and throughput performance of the hard disk. The terminal device described in 1. The hard disk status information is score information obtained by scoring at least one of the cumulative energization time, temperature, read error occurrence rate, number of defective sectors, and throughput performance of the hard disk. The terminal device according to claim 7. 9. The registration message transmitting means transmits the registration message to another terminal device via the network when the content information is stored in the hard disk or periodically. The terminal device according to claim 1. In the terminal device in the information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices,
Information acquisition means for acquiring location information of a plurality of other terminal devices each holding desired content information in the hard disk and status information of the hard disk of each of the other terminal devices via the network;
Based on the status information of the hard disk acquired by the information acquisition means, selection means for selecting one terminal device among the plurality of other terminal devices that acquired the location information;
A terminal device comprising: content acquisition means for acquiring the desired content information from the selected other terminal device via the network. The selection means includes
Among the other terminal devices whose location information is acquired by the information acquisition means, when there are a plurality of other terminal devices whose state information of the hard disk satisfies a predetermined condition, one of those terminal devices is randomly selected. The terminal device according to claim 10, wherein the terminal device is selected. The selection means includes
Among the other terminal devices whose location information is acquired by the information acquisition means, when there are a plurality of other terminal devices whose hard disk status information satisfies a predetermined condition, the predetermined condition is selected from those terminal devices. The terminal device according to claim 10, wherein a terminal device that satisfies a high degree of satisfaction is selected. The hard disk status information is information based on at least one of an energization accumulation time, temperature, read error occurrence rate, number of defective sectors, and throughput performance of the hard disk. The terminal device as described in any one of -12. The hard disk status information is score information obtained by scoring at least one of the cumulative energization time, temperature, read error occurrence rate, number of defective sectors, and throughput performance of the hard disk. The terminal device according to claim 13.   An information processing program for causing a computer to function as the terminal device according to any one of claims 1 to 14. In the information processing method of the terminal device in an information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices,
Acquiring content identification information for identifying content information, location information of another terminal device holding the content information in the hard disk, and status information of the hard disk of the other terminal device via the network;
Storing the acquired information;
Determining whether the status information of the hard disk of the other terminal device satisfies a predetermined condition when there is a transmission request for the location information of the other terminal device holding the content information;
When the status information of the hard disk satisfies a predetermined condition, the location information of the other terminal device is extracted from the storage means and transmitted to the requesting terminal device. Information processing method. In the information processing method of the terminal device in an information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices,
Storing the content information on a hard disk;
Obtaining status information of the hard disk from the hard disk;
Transmitting a registration message including identification information of content information stored in the hard disk, location information of the device itself, and status information of the hard disk to a predetermined terminal device via the network. Information processing method of the apparatus. In the information processing method of the terminal device in an information distribution system formed by participation of a plurality of terminal devices connected to each other via a network and transmitting / receiving content information between the terminal devices,
Obtaining the location information of a plurality of other terminal devices each holding desired content information in the hard disk and the hard disk status information of each of the other terminal devices via the network;
Selecting one terminal device among the plurality of other terminal devices that have acquired the location information based on the acquired state information of the hard disk; and
Obtaining the desired content information from the selected other terminal device via the network. An information processing method for a terminal device, comprising:

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