JP2014044683A - Communication device and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a file system of a recording medium of a writing destination from being damaged and realize high-speed data transfer by switching the processing content according to an address of a recording destination in data registration through a network.SOLUTION: It is determined whether a received command is a write command for management information of a file system to a storage area in a recording medium (S501). In the situation where it is determined the received command is the write command for the management information of the file system to the storage area in the recording medium, when received write data for management information to a storage area is not normal, writing of data to a recording medium is prohibited (S506).

Description

  The present invention relates to a communication apparatus, and more particularly to an apparatus for recording a signal received from outside on a recording medium.

  Conventionally, in an information communication device such as a mobile phone, data is transmitted and received by wireless communication (for example, see Patent Document 1). For example, data transmitted from a transmitting device is received by a receiving device, and the received data is recorded on a recording medium such as a memory card.

  In the memory card, data is exchanged by near field communication (NFC).

JP 2003-061041 A

  In wireless communication, communication may be cut off due to interference or obstacles of other wireless devices or when the distance is long. Therefore, the protocol used for communication is generally application communication. For example, in the case of an IP network protocol, data is transmitted and received in units of files, such as FTP (File Transfer Protocol). This did not have a significant impact on the system even if the communication was interrupted.

  However, in such a communication method in units of files, a search for a recording position of received data and a management process occur, so that overhead increases and transmission efficiency is poor.

  On the other hand, there is a USB or the like as an interface for connecting a general recording medium and a system. In USB, a mass storage protocol is generally employed for communication with a recording medium. Unlike FTP, this protocol depends on the recording medium. In other words, because the sending side designates where to record on the recording medium and sends the data, the mass storage program processing is lighter in load than the communication method in units of files such as FTP, so there is less overhead and high speed. Transfer can be realized. However, in the case of this communication method, there is a possibility that the recording medium is destroyed when communication is cut off. For example, data recorded on a memory card or the like is generally managed as a file according to a file system such as a FAT file system. If communication is cut off during the transmission of management information in the file system, there is a possibility that information recorded on the recording medium cannot be read.

  The present invention has been made in view of such problems, and an object thereof is to enable data to be received and recorded at high speed and safely.

  According to one aspect of the present invention, a communication means for communicating with an external device, a recording medium for storing data, and a recording / reproducing means for writing and reading data to and from the recording medium according to a predetermined file system Detection means for detecting that the command received by the communication means is a write command to the storage area of the management information of the file system in the recording medium; and storage of the management information detected by the detection means There is provided a communication device comprising control means for prohibiting writing of data to the recording medium by the recording / reproducing means when data by an area write command is not normal.

  According to the present invention, data can be received and recorded at high speed and safely.

The figure which shows the structure of the communication system in embodiment. The figure which shows the structure of the transmitter in embodiment, and a receiver. The schematic diagram of the storage area in the recording medium with which management information was memorize | stored. The flowchart which shows the data transmission process by the transmitter in embodiment. The flowchart which shows the data reception process by the receiver in embodiment. The figure which shows the structural example of the packet data in embodiment. The figure which shows the register for memorize | storing the management information in embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment, It shows only the specific example advantageous for implementation of this invention. Moreover, not all combinations of features described in the following embodiments are indispensable for solving the problems of the present invention.

  FIG. 1 is a block diagram illustrating a configuration example of a communication system according to the present embodiment. In FIG. 1, a transmission apparatus 101 and a reception apparatus 102, which are communication apparatuses, are information processing apparatuses each having the configuration shown in FIG. The transmission apparatus 101 and the reception apparatus 102 communicate by wireless communication to transmit / receive data. In the present embodiment, the transmission device 101 may be a device including a large-capacity recording medium such as a personal computer, and the reception device 102 may be a portable device such as a mobile phone.

  FIG. 2 is a diagram illustrating the configuration of the transmission device 101 and the reception device 102. In FIG. 2, a transmission apparatus 101 and a reception apparatus 102 have the same configuration. In the following description, the configuration of the transmission apparatus 101 will be described. Since the receiving apparatus 102 has the same configuration as that of the transmitting apparatus 101, detailed description of each part of the receiving apparatus 102 is omitted. Common reference numerals are assigned to components corresponding to the transmission apparatus 101 and the reception apparatus 102. However, at the end of each reference number, a letter “a” indicating that it is a component of the transmitting apparatus 101 or a character “b” indicating that it is a component of the receiving apparatus 102 is further added. .

  The control unit 201a controls the entire operation of the transmission apparatus 101 in accordance with an input from the operation unit 202a. The control unit 201a includes a microcomputer, a memory, and the like, and controls the transmission device 101 according to a program (software) stored in a memory (not shown). The operation unit 202a includes various switches that can be operated by the user. The operation unit 202a accepts various instructions from the user and notifies the control unit 201a. The operation unit 202a includes a power switch, a user interface for starting data transmission, and selecting data to be transmitted.

  The display control unit 203a displays various types of information on the display unit 204a according to instructions from the control unit 201a. The display unit 204a includes a display device such as a liquid crystal panel. The memory 205a stores various data such as received data. The bus 206a transmits and receives data between the units of the transmission apparatus 101.

  The recording / playback unit 207a writes and reads various information to and from the recording medium 208a. In the present embodiment, the recording medium 208a is a random access recording medium such as a hard disk (HDD) or a flash memory card. The recording / playback unit 207a manages the data recorded on the recording medium 208a as a file according to a file system such as FAT (File Allocation Table). In addition, the recording medium 208a can be easily mounted and discharged from the receiving apparatus 102 by a mounting / discharging mechanism (not shown), but the recording apparatus 208a may be built in the transmitting apparatus 101. .

  The communication unit 209a transmits and receives data, other commands, and the like to and from an external device by wireless communication using the antenna 210a. As will be described later, the data determination unit 211a determines the content of the received command and the designated address. The bus 212a is a dedicated bus for transmitting and receiving data between the recording / reproducing unit 207a and the data determining unit 211a. The buffer memory 213a temporarily stores commands, addresses, and data received by the data determination unit 211a.

  Next, processing for transmitting data from the transmission apparatus 101 to the reception apparatus 102 and recording the received data on the recording medium 208b in the reception apparatus 102 will be described.

  FIG. 4 is a flowchart showing data transmission processing by the transmission apparatus 101. The program corresponding to the flowchart of FIG. 4 is stored in, for example, the memory 205a, and the data transmission process is realized by the control unit 201a reading and executing the program and controlling each unit.

  The user operates the operation unit 202a to instruct display of a selection screen for selecting data to be transmitted. When the display of the selection screen is instructed, the control unit 201a instructs the recording / playback unit 207a to read management information related to the file system from the recording medium 208a. The recording / playback unit 207a reads management information related to the file system from the recording medium 208a and stores it in the memory 205a. The management information is information for managing the recording position of data recorded on the recording medium 208a, the free area of the recording medium 208a, and the like. For example, in the FAT file system, the management information is FAT, root directory entry, or information on each directory entry. The control unit 201a detects a file recorded on the recording medium 208a based on the management information stored in the memory 205a, and performs display control so as to generate a selection screen for selecting transmission target data (file). The unit 203a is instructed. The display control unit 203a generates a selection screen and displays it on the display unit 204a.

  The user operates the operation unit 202a to select data to be transmitted from the data displayed on the display unit 204a (S401). When the transmission data is selected, the control unit 201a requests the receiving device 102 to transmit the management information of the recording medium 208b in the receiving device 102 from the communication unit 209a (S402). The communication unit 209a sends a management information transmission command from the antenna 210a to the receiving apparatus 102 in accordance with an instruction from the control unit 201a.

  In the receiving device 102, the communication unit 209b receives the management information transmission command from the transmitting device 101 via the antenna 210b, and sends it to the data determination unit 211b. As will be described later, the data determination unit 211b detects that the received command is a write command. Here, since the received command is a management information transmission command, the data determination unit 211b sends the received command to the control unit 201b. In response to the management information transmission command, the control unit 201b instructs the recording / playback unit 207b to read the management information of the recording medium 208b in the receiving apparatus 102. The recording / playback unit 207b reads management information from the recording medium 208b and stores it in the memory 205b. The control unit 201b instructs the communication unit 209b to transmit the management information stored in the memory 205b. The communication unit 209b reads management information from the memory 205b and sends the management information to the transmission apparatus 101 via the antenna 210b.

  In the transmission device 101, the communication unit 209a receives the management information transmitted from the reception device 102 and sends it to the data determination unit 211a (S403). The data determination unit 211a sends the received management information to the control unit 201a. Based on the received management information, the control unit 201a instructs the display control unit 203a to display the folder in the recording medium 208b of the receiving apparatus 102 on the display unit 204a. The display control unit 203a displays the folder of the recording medium 208b on the display unit 204a (S404). The user operates the operation unit 202a to select a folder for recording the transmitted data from the folders displayed on the display unit 204a (S405). When the transmission destination folder is selected, the control unit 201a generates a write command for instructing the selected folder to write the selected data based on the management information received from the receiving apparatus 102.

  The control unit 201a detects a free area in the recording medium 208b based on the management information received from the receiving device 102. Then, from this empty area, an address for recording transmission data is determined, and a write command including a write address is generated. Further, the control unit 201a generates management information that needs to be changed in accordance with the writing of transmission data to the recording medium 208b, based on the management information received from the receiving device 102. For example, the directory entry related to the folder designated as the recording destination of the transmission data and the FAT information are changed. Then, a write command including the changed management information and write address is generated.

  The control unit 201a instructs the communication unit 209a to transmit a write command and transmission data (S406). The communication unit 209a sends a write command and transmission data to the receiving device 102. In this embodiment, a command is transmitted as the format of the packet data 601 shown in FIG. The packet data 601 includes a command field 602 indicating processing contents such as reading and writing, and an address field 603 indicating a logical address. The packet data 601 includes a data length field 604 indicating the length of data to be written and read, and a data field 605 in which data to be transmitted is stored.

  Next, data reception processing in the receiving apparatus 102 will be described. FIG. 5 is a flowchart showing data reception processing by the reception apparatus 102. Note that a program corresponding to the flowchart of FIG. 5 is stored in, for example, the memory 205b, and the data reception process is realized by the control unit 201b reading and executing the program and controlling each unit.

  As described above, when a command is transmitted from the transmission apparatus 101, the communication unit 209b receives the command via the antenna 210b and sends the command to the data determination unit 211b. The data determination unit 211b stores the received command in the buffer memory 213b. When the data determination unit 211b receives a command, the flow of FIG. 5 is started.

  First, the data determination unit 211b determines whether or not the received command is a data write command (S501). If it is not a data write command, the data determination unit 211b sends the received command to the control unit 201b, and the control unit 201b executes processing corresponding to the command (S508).

  If the received command is a write command, the data determination unit 211b determines whether the write address included in the command is a predetermined address (S502). The data determination unit 211b has a built-in register 700 for storing a logical address where management information in the recording medium 208b is recorded. FIG. 7 shows a register for storing management information. In FIG. 7, a storage start address 701 and a storage end address 702 for management information are stored in the register 700. For example, as shown in FIG. 3, when management information is stored in an area 302 between addresses 0x0000BE00 to 0x0040BE00 in the storage area 301 in the recording medium 208b, these addresses are stored in the register 700. When the address management information is distributed and stored in a plurality of areas in the recording medium 208b, the top logical address and the end logical address of each area are stored in the register 700, respectively. The data determination unit 211b detects all the storage areas of the management information stored in the recording medium 208b when the power of the receiving apparatus 102 is turned on or when the recording medium 208b is newly installed. 700 is stored.

  The data determination unit 211b determines whether the write address included in the received command is included in any one of the storage areas specified by the one or more storage start addresses and storage end addresses stored in the register 700. .

  If the received address is not included in the management information storage area, the data determination unit 211b reads the received data from the buffer memory 213b and sends it to the recording / playback unit 207b via the bus 212b (S507). The recording / playback unit 207b records data at a specified address on the recording medium 208b based on the received command.

  If the received address is included in the management information storage area, the data determination unit 211b outputs an interrupt signal to the control unit 201 to the effect that there has been a write request to the management information storage area (S503). The control unit 201b controls the data determination unit 211b according to the interrupt signal, reads the data received from the buffer memory 213b, and stores it in the memory 205b (S504). The control unit 201b determines whether or not the data stored in the memory 205b is normal (S505). The fact that the address included in the received write command is included in the management information storage area in the recording medium 208b means that the data to be written is management information defined by the file system. For this reason, the control unit 201b confirms whether or not the received data to be written has a correct value defined by the FAT file system. For example, the control unit 201b determines that the received data is not correct when indefinite data such as a defective cluster is stored in a place where a value indicating the end of the cluster in which management information is stored is to be stored. To do. Alternatively, when the cluster chain specified by the FAT is looped, it is determined that the data is not correct.

  If it is determined that the data is normal, the control unit 201b reads the data from the memory 205b, sends the data to the recording / reproducing unit 207b, and records the data at the designated address in the recording / reproducing unit 207b (S507).

  If it is determined that the data is not normal, the control unit 201b stops the transmission of the write command and data to the recording / reproducing unit 207b, and prohibits the writing of the received data (S506). As described above, when the data writing is not normally completed, the control unit 201b transmits a command indicating that the data writing is not completed to the transmission apparatus 101 through the communication unit 209b.

  As described above, according to the present embodiment, when a management information write command is received, the received data is temporarily stored in the memory to check whether the contents are correct. For this reason, it is possible to prevent the data from being read out due to the error during transmission or the disconnection of the wireless communication, which causes bad data to be written in the management information area of the recording medium 208b.

  Also, according to the present embodiment, when a command for writing data other than management information is received, the command and data are sent as they are to the recording / reproducing unit, so that data can be written at high speed.

  In this embodiment, the data is managed according to the FAT file system. However, the present invention can be similarly applied to a case where a file system other than FAT is used. In addition, in the receiving apparatus 102 in FIG. 2, when a plurality of recording media can be mounted, a management information storage area is stored in a register for each recording medium. In this embodiment, the communication is performed by wireless communication, but wired communication can also be used.

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed. In this case, the program and the storage medium storing the program constitute the present invention.

Claims (5)

A communication means for communicating with an external device;
A recording medium for storing data;
Recording and reproducing means for writing and reading data to and from the recording medium according to a predetermined file system;
Detecting means for detecting that the command received by the communication means is a write command to the storage area of the file system management information in the recording medium;
Control means for prohibiting writing of data to the recording medium by the recording / reproducing means when data by a write command to the storage area of the management information detected by the detecting means is not normal;
A communication apparatus comprising: A register for storing information relating to the storage area of the management information in the recording medium;
When the detection means includes a write address included in the command received by the communication means in the storage area stored in the register, the command received by the communication means is the management information in the recording medium. The communication device according to claim 1, wherein the communication device is determined to be a write command to the storage area.   When the write address included in the command received by the communication means is not included in the storage area stored in the register, the recording / reproducing unit stores data in the write address included in the command of the recording medium. The communication apparatus according to claim 1, wherein the communication apparatus records the information. A communication means for communicating with an external device;
A recording medium for storing data;
Recording and reproducing means for writing and reading data to and from the recording medium according to a predetermined file system;
A method for controlling a communication device having
A detecting step for detecting that the command received by the communication unit is a write command to the storage area of the management information of the file system in the recording medium;
A control step for prohibiting writing of data to the recording medium by the recording / reproducing means when the data by the write command to the storage area of the management information detected in the detection step is not normal;
A method for controlling a communication apparatus, comprising:   The program for making a computer perform each step of the control method of the communication apparatus of Claim 4.

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