JP2000322309A - File transmission device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To retransmit data efficiently in the case of transmitting data over a plurality of connections and failing or interrupting data transmission in the middle. To provide a file transmission device. A data reading device reads a transmission target file stored on a magnetic disk by virtually dividing the file. The transmitting devices 5a to 5c share the transmission of the divided files, and the receiving devices 12a to 12c
c. The data writing device 13 is a receiving device 12a
12c to virtually combine the divided files received and write them to the magnetic disk drive. Receiving device 12a
12c create a reception log holding the amount of received data, and the transmission devices 5a to 5c receive the reception log from the reception device when resuming the file transmission halfway, and obtain a transmission restart position from the received data amount.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a file transmission apparatus, and more particularly to a file transmission apparatus suitable for non-real-time transmission of a large-capacity file such as moving image data.

[0002]

2. Description of the Related Art Conventional file transmission, for example, file transmission on the Internet, uses a well-known TCP transmission.
/ IP protocol is used. This protocol has a function of retransmitting erroneous data during transmission, and finally has a feature that an error-free file can be transmitted to a transmission partner. However, when the transmission path delay is large, the response of whether or not the communication has been normally received is delayed from the communication partner, so that the transmission of the next new data is delayed, and as a result, the throughput is reduced. In particular, a high throughput cannot be obtained in an environment with a large delay such as between the United States and Japan or a satellite link.

On the other hand, in the conventional file transmission, a function of establishing a plurality of connections between a transmitting side and a receiving side and transmitting data in parallel has been proposed. By using this function, it is possible to greatly improve the throughput when transmitting a large-capacity file such as moving image data.

[0004]

However, in the prior art for transmitting data by establishing a plurality of connections as described above, after the transmission fails during the data transmission or the data transmission is intentionally interrupted, When transmitting again, it is necessary to retransmit the data from the beginning, and there has been a problem in reliability or efficiency.

[0005] An object of the present invention is to eliminate the above-mentioned problems of the prior art and to transmit data over a plurality of connections. In the case where data transmission fails or is interrupted in the middle of the transmission. It is another object of the present invention to provide a file transmission device capable of efficiently retransmitting data.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a data reading means for virtually dividing a transmission target file stored in a magnetic disk drive into files and reading the data. Transmitting means for transmitting the divided file read from the means by using a plurality of TCP / IP connections, receiving means for receiving the divided file sent from the transmitting means, and receiving by the receiving means A first feature resides in that a data writing means for virtually synthesizing the divided file and writing the divided file into the magnetic disk device is provided.

[0007] The receiving device has a receiving log for holding the amount of received data, and the transmitting device receives the receiving log from the receiving device when the file transmission is restarted halfway, and transmits the received log from the received data amount. A second feature is that the restart position is obtained. Further, both the transmission side and the reception side are provided with a transfer control device, and when the transfer control device on the reception side receives a notification that the reception has been completed from all of the reception devices, it determines that the file transmission has been completed. The third feature is that the transfer control device forcibly terminates all the transmission devices and the reception devices when notified that a transmission error has occurred from the transmission device or the reception device. .

According to the first feature, the file to be transmitted is virtually divided into files, the data is read, and the received divided files are virtually combined and written into the magnetic disk drive. File division can be performed in a short time, and efficient data transmission can be performed.

Further, according to the second feature, when data transmission fails or is interrupted during file transmission, data can be retransmitted from the next data of the received data amount. Therefore, data transmission can be performed efficiently. Further, according to the third feature, when data transmission fails or is interrupted,
Since all the transmitting devices and the receiving devices are forcibly terminated, retransmission from the beginning of data transmission can be started early, and as a result, data transmission can be performed efficiently.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of an embodiment of the present invention.

A transmitting device 1 for transmitting a file includes a magnetic disk for storing a file such as a video file, for example, a hard disk (HD) 2, a characteristic extracting device 3 for extracting characteristic data of the file, and a file from the hard disk 2. A plurality of connections (pipe) are formed between the data reading device 4 to be read, a plurality of transmitting devices 5 (5a, 5b, 5c) for transmitting data read from the data reading device 4, and a receiving device of a communication partner. And a transfer control device 6 for transmitting / receiving various control data to / from the receiving device and performing other controls.

The receiving device 10 establishes a connection with the transmitting device 1, exchanges control data, and performs other control, and a plurality of receiving devices 12 (12a , 12b, 12c), a data writer 13 that writes files received by the receiver 12 in parallel to the hard disk 14, and a feature extractor 15 that extracts features from the data written to the data writer 13. It is composed of The transfer control devices 6 and 1
1 are connected by a control line 20, and a plurality of connections 21 are established from the transmitting device 5 to the receiving device 12 as a result of the establishment of the connection.

Next, the operation of the transmitting apparatus 1 of the present embodiment will be described with reference to the flowchart of FIG. In step S1, a connection is established. The transfer control device 6 of the transmitting device transmits an FTP (File Transfer Protocol) request command to the transfer control device 11 of the receiving device. In response, the transfer control device 11 returns an FTP response command in step S20 (see FIG. 4) described later. At this time, the command response time is measured. Thereafter, the transfer control device 6 of the transmitting device determines the number of connections established between the transmitting device and the receiving device, the file capacity to be transmitted, and the command response time measured in the connection establishment stage. It is dynamically determined by the above method. In the following description, the number of connections is N
Book.

In step S2, the feature extracting device 3 extracts feature data from a file to be transmitted in the hard disk 2. For example, as shown in FIG. 6 (a), the data of the head, the 100th byte, the 200th byte,..., For example, 0, 1, 1,. Alternatively, as shown in FIG. 6B, the data amount of each of the first frame, the second frame,.
, 360 bytes,... Are extracted as feature data.

In step S3, the data reading device 4 virtually divides the file stored in the hard disk 2 into N (N is a positive integer) for each of the transmitting devices 5a to 5c. As an example, the file is divided into N equal parts. If the file is divided into N equal parts, the size of each divided file is a value obtained by truncating the fraction except for the last Nth divided file, and only the last Nth divided file is truncated. It is assumed that the fraction generated by the above is added. In step S4, N file pointers are prepared. Specifically, as an initial operation, the file pointer is moved to a position obtained by dividing the file on the hard disk 2 into N equal parts. Thereafter, data is read from the hard disk (HD) 2 using the N file pointers.

In step S5, data such as the number of connections, the size of the entire file to be transmitted, and the characteristic data of the file are transmitted from the transfer control device 6 of the transmitting device to the transfer control device 11 of the receiving device. . The feature data is encrypted as necessary and transmitted to the receiving side.

In step S6, N transfer routines are activated to transmit each of the N equally divided files. During data transmission, data is read from the respective positions of the N file pointers, and the data is passed to each of the transmission devices 5a to 5c. One operation of the transfer routine will be described with reference to FIG. 3, taking the transmitting device 5a as a representative.

A receiving device 12a corresponding to the transmitting device 5a
Has a reception log indicating the amount of received data (see step S45 in FIG. 5). In step S11, the transmitting device 5a transmits information based on the reception log from the receiving device 12a, that is, step S42 or S50 described later.
(See FIG. 5), whether the transfer is an initial transfer or a re-transfer
In the case of retransmission, information on the amount of received data is received. In step S12, the transmitting device 5a moves the file pointer according to the information based on the reception log. Thereby, the data reading device 4 supplies the data starting from the transfer start position to the transmitting device 5a. At the start of transmission, a notification of the initial transfer is received from the receiving device 12a, so that the file pointer is moved to the transfer start position in step S12.

Next, in step S13, the transmitting device 5a
Reads K bytes (K is a positive integer) of data from a file and transmits it to the receiving device 12a. In step S14, it is determined whether or not the transmission has been successful within a predetermined T1 seconds. If this determination is affirmative, the process proceeds to step S15, where it is determined whether or not all of the division files in charge have been transmitted. If the determination is negative, the process proceeds to step S16, and the read position pointer is moved by K bytes of data. Next, the process proceeds to step S13 to read and transmit K-byte data from the read position pointer moved by the K-byte data.

On the other hand, if the determination in step S14 is negative, the process returns to step S11 to receive information based on the reception log from the receiving side. That is, step S5 in FIG.
It receives the retransmission from 0 and the received data amount.
Therefore, in step S12, the file pointer is moved to the next data position of the transmitted data obtained based on the received data amount, and the transmission is restarted. This makes it possible to efficiently retransmit data when data transmission fails or is interrupted halfway.

With the above operation, the transmitting device 5a transmits all of its own divided files, and if the determination in step S15 is affirmative, the process proceeds to step S17, where a receiving completion message is received within a predetermined T2 seconds. It is determined whether or not it has been done. When this judgment is affirmative, step S1
In step 8, a transmission completion notification is sent to the transfer control device 6. If the determination in step S17 is negative, the process proceeds to step S1.
Returning to step 1, the same operation as described above is executed.

As described above, step S in FIG.
When the operation of Step 6 is completed, the process proceeds to Step S7, and the transfer control device 6 determines whether or not transmission completion notifications have been received from all the transmitting devices 5a to 5c. If this determination is affirmative, the transmission process ends.

Next, the operation of the receiving apparatus 10 will be described with reference to the flowcharts of FIGS. In step S20, a connection is established by returning an FTP response command to the transfer control device 6, corresponding to step S1 (see FIG. 2). In step S21, corresponding to step S5, data such as the number of connections, the size of the entire transmitted file, and the characteristic data of the file are received from the transfer control device 6. When the encrypted feature data is received, it is decrypted after the reception.

In step S22, the sectors on the hard disk 14 cannot be continuously obtained unless the file write area is secured on the hard disk 14. Therefore, the sectors on the hard disk 14 cannot be obtained according to the file size obtained in the communication in step S21. A dummy file is created in advance, and a file area is reserved in advance. In step S23, the position where the file area is divided into N is determined, and in step S24, N file pointers are prepared.

In step S25, N reception routines are started. One operation of the receiving routine is performed by the receiving apparatus 1
2a will be described as a representative. FIG. 5 shows the receiving device 12.
5 is a flowchart illustrating the operation of FIG. Step S
At 41, it is determined whether or not there is an error end record in the reception log. Initially, this determination is negative, so the process proceeds to step S42 to notify the transmitting side of the initial transfer. In step S43, the file pointer is moved to the head of the reception position. In step S44, it is determined whether or not the received data has arrived within a predetermined T3 seconds. If this determination is affirmative, the process proceeds to step S45, where the received data is written to the hard disk, and the received data amount is recorded in the reception log. On the other hand, if the data transmission fails or is interrupted halfway, and the determination in step S44 is negative, the process proceeds to step S49, and the end of error is recorded in the reception log.

In step S46, a determination is made as to whether or not the last data in charge of its own routine has been received. If the determination is negative, the process returns to step S43 to move the file pointer to the head of the next reception position. You. On the other hand, when the determination is affirmative, the process proceeds to step S47, and a reception completion message is transmitted to the transmission device 5a. In step S48,
A reception completion notification is sent to the transfer control device 11.

When the end of the error is recorded in the reception log in step S49, the process returns to step S41, and it is determined whether or not the end of the error is recorded in the reception log. This time the determination is affirmative and the process proceeds to step S50. In step S50, the transmission device 5a is notified of the retransmission and the received data amount. In step S51, the file pointer is moved to the received position to prepare for receiving the retransferred data.

As described above, step S25 in FIG.
Is performed, the process proceeds to step S26, where the transfer control device 11 determines whether or not reception completion notifications have been received from all the receiving devices 12a to 12c. If this determination is affirmative, the process proceeds to step S27 where the hard disk 14
The N divided files stored above are combined. In step S28, the feature extraction device 15 extracts feature data from the synthesized file. In step S29, it is determined whether or not the feature data matches. If they match, the process proceeds to step S30, where the data is determined to be normal or intrinsic data. On the other hand, if they do not match, the flow advances to step S31 to determine that the data is invalid.

As described above, according to the present embodiment, a plurality of connections are established between a transmitting apparatus and a receiving apparatus, a divided file is transferred through each connection, and data transmission fails during the connection. In the case of interruption or interruption, the amount of received data can be detected from the reception log, and data can be retransmitted from the data following the received data, so that file transmission can be performed efficiently.

Next, another embodiment of the present invention will be described with reference to FIGS. In these figures, FIG.
The same steps as those in FIG. 3 and FIG.

In this embodiment, when the determination in step S7 in FIG. 7 is negative, the process proceeds to step S61, and the transfer control device 6 determines whether or not the transmission device 5 has notified the transmission failure. When this determination is affirmative, step S62
To terminate all the transfer routines. In FIG. 8, when the determination in step S14 or step S17 is negative, the process proceeds to step S63 or step S64 to notify the transfer control device 6 of transmission failure. on the other hand,
In the receiving device 10, when the error end is recorded in the reception log in step S49 in FIG. 5, the error end is notified to the transfer control device 11. Upon receiving the error end notification, the transfer control device 11 forcibly ends all reception routines.

According to this embodiment, if transmission failure or reception error end occurs in one of the transfer routines or reception routines, all transfer and reception routines are forcibly terminated. Therefore, retransmission from the beginning of the file can be started at an early stage, and data can be retransmitted efficiently.

[0033]

As is apparent from the above description, according to the present invention, when data is transmitted over a plurality of connections, the transmission target file stored in the magnetic disk device is virtually divided into files. And read,
Further, since the divided files received by the receiving means are virtually synthesized and written into the magnetic disk device, the time required for dividing the files can be reduced, and the files can be transmitted with high efficiency.

Further, when data transmission fails or is interrupted during file transmission, data can be retransmitted from the data following the amount of received data, so that data transmission can be efficiently performed. Will be able to do it.
Furthermore, when data transmission fails or is interrupted, all transmitting and receiving devices are forcibly terminated, so that retransmission from the beginning of data transmission can be started early, resulting in data transmission. It can be done efficiently.

Further, a dummy file having a size of a file to be received is once created on the magnetic disk on the receiving side, and the data writing means overwrites the received data on the dummy file. Can be continuously obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an embodiment of a file transmission device according to the present invention.

FIG. 2 is a flowchart illustrating an operation of a transmitting device.

FIG. 3 is a flowchart showing a detailed operation of step S6 in FIG. 2;

FIG. 4 is a flowchart showing the operation of the receiving device.

FIG. 5 is a flowchart showing a detailed operation of step S25 in FIG. 4;

FIG. 6 is an explanatory diagram of a specific example of feature extraction data.

FIG. 7 is a flowchart showing the operation of the second embodiment of the present invention.

8 is a flowchart showing a detailed operation of step S6 in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transmission side apparatus, 2 ... Magnetic disk, 3 ... Feature extraction apparatus, 4 ... Data reading apparatus, 5 ... Transmission apparatus, 6 ... Transfer control apparatus, 10 ... Reception side apparatus, 11 ... Transfer control apparatus, 12 ...
Receiving device, 13: data writing device, 14: magnetic disk, 15: feature extracting device, 20: control line, 21: connection.

Continuation of the front page (72) Inventor Masahiro Wada 2-1-15 Ohara, Kamifukuoka-shi, Saitama F-term in Kadidi Research Institute Co., Ltd. 5B082 HA05 5B089 GA23 HB02 JA32 JB04 KA05 KA12 KC53 KG04 KH30 ME08

Claims (8)

[Claims] 1. A data reading means for virtually dividing a transmission target file stored in a magnetic disk device and reading the divided file, and a plurality of TCP / IP connections for dividing the divided file read from the data reading means. Transmitting means for transmitting the divided files transmitted from the transmitting means, and data to be virtually combined with the divided files received by the receiving means and written into the magnetic disk drive A file transmission device comprising a writing unit. 2. The file transmission device according to claim 1, wherein the data reading unit performs data reading using an individual file pointer for each of the transmitting units, and the data writing unit performs individual data reading for each of the receiving devices. A file transmission device for performing data writing using the file pointer. 3. The file transmission device according to claim 1, wherein the reception device has a reception log for holding a received data amount, and the transmission device stores the reception log when the file transmission is restarted halfway. A file transmission device wherein information based on the received data is received from the receiving device, and a transmission restart position is obtained from the received data amount. 4. The file transmission device according to claim 1, further comprising a transfer control device on both the transmission side and the reception side, wherein the transfer control device on the reception side has completed reception from all of the reception devices. Receiving the notification of the above, it is determined that the file transmission is completed. 5. The file transmission device according to claim 4, wherein the transfer control device forcibly removes all transmission devices and reception devices when notified that a transmission error has occurred from the transmission device or the reception device. A file transmission apparatus characterized in that the file transmission is terminated. 6. The file transmission device according to claim 1, wherein a dummy file having a size of a file to be received is once created on a magnetic disk on a receiving side, and the data writing means overwrites the received data on the dummy file. A file transmission device. 7. The file transmission apparatus according to claim 1, wherein characteristic data of the file is extracted from the transmission target file, and the characteristic data is transmitted to a receiving side. A file transmission apparatus characterized in that the authenticity of a file is confirmed by comparing the extracted data with characteristic data extracted from the file. 8. The file transmission device according to claim 7, wherein the transmitting side encrypts the characteristic data and transmits the encrypted characteristic data to the receiving side.