JPH11353249A - File system and file transfer method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speed up file transfer through a network by reducing an overhead accompanied by the movement of data in a main storage device and direct memory access DMA to a network interface. SOLUTION: When a file is generated, a header is connected to data and they are stored in a secondary storage device 12. At the time of file transfer, contents stored in a buffer 22 in an operating system 10 are read out in the state that the header is connected to the data and after necessary information is written in the header part, the file is passed as it is in the form of packets to be sent to the network interface 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing system using a network, and more particularly to a file management method suitable for an information processing system including a process of transferring a file from a server to a client via a network. About.

[0002]

2. Description of the Related Art In a computer environment in which a plurality of computers are connected to a network, a certain computer (client computer) is stored in a secondary storage device of the server computer with respect to another computer (server computer). When a specific file is requested and the server transfers the specified file to another computer in response to the request, the server operates as shown in FIG.

In FIG. 2, a server machine 1 and a client machine 2
Are connected to the network 3 by the cable 4. In the client machine 2, the client program 1
4 is working. Further, the server machine 1 includes one or more processors and a main storage device, and the server program 46 and the operating system 10 operate. Further, the server machine 1 includes a secondary storage device 12 and a network interface 11. Here, the secondary storage device is, for example, a magnetic disk, a magneto-optical disk,
Examples include a magnetic tape and a CD-ROM. The cable 4 connected to the server 1 is connected to a network interface 11.

Operating system 1 of server machine 1
0 includes the file system 40 and the protocol processing unit 41. The server program 46 stores a user buffer 47, and the protocol processing unit 41 stores a data buffer 45.
And a header buffer 44. Here, the user buffer 47, data buffer 45, header buffer 44
Are storage areas secured on the main storage device of the server machine 1, respectively.

In FIG. 2, a client program 14 of a client machine 2 sends a plurality of files 42, 42 ',... Stored in a secondary storage device 12 to a server machine 1.
Is requested by the server program 46 when the transfer of the file 42 is requested. Server program 46 that has received the file transfer request
Requests the file system 40 of the operating system 10 to transfer the file to the user buffer 47 secured in the server program 46. The file system 40 that has received the request is the secondary storage device 1
2 is instructed to transfer the file 42 to the user buffer 47. The secondary storage device 12 receiving the instruction,
The file 42 is transferred to the user buffer 47.

When the transfer is completed, the server program 46
Requests the protocol processing unit 41 of the operating system 10 to transmit the contents of the user buffer 47 to the client machine 2. Upon receiving the request, the protocol processing unit 41 first stores the contents of the user buffer 47 in the data buffer 45 in the protocol processing unit 41.
Copy to Next, the protocol processing unit 41 creates data called a header in the header buffer 44 secured in the protocol processing unit 41 so that the contents of the data buffer 45 reach the client machine 2 correctly.
In this header, information for identifying the client machine 2 from among a plurality of computers connected to the network 3 is described.

When the creation of the header is completed, the protocol processing unit 41
The contents of the header buffer 44 and the contents of the data buffer 45 are concatenated and transmitted to the network 3.
Upon receiving the instruction, the network interface 11 converts the contents of the header buffer 44 and the contents of the data buffer 45 into
The packet is sequentially transferred to the packet buffer 26 secured in the network interface 11. At this time, the contents of the header buffer 44 and the contents of the data buffer 45 are transferred in such a manner that the network interface 11 accesses the main memory of the server machine 1 by direct memory access (DMA).

Further, the contents of the header buffer 44 and the contents of the data buffer 45 are transferred so that the contents of the two are connected on the packet buffer 26. When the transfer to the packet buffer 26 is completed, the network interface 11 transmits the contents of the packet buffer 26 to the cable 4. The contents of the packet buffer 26 transmitted here reach the client machine 2 via the network 3 if the header created by the protocol processing unit 41 is correct, and the file transfer is completed.

[0009]

However, the file transfer method described in the section of the prior art has the following problems.

First, the file 42 on the secondary storage is first transferred to the user buffer 47, then copied to the data buffer 45, and then transferred to the packet buffer 26 (along with the header). A file is moved at least once in the device, and the process for that takes time.

Second, the network interface 11
However, when trying to access the main storage device by means of the above-mentioned DMA, transfer by one DMA is usually limited to a continuous area of the main storage device. However, the data buffer 45 and the header buffer 44 are one area on the main storage device, but are not continuous. Therefore, in order to transfer the contents of the two to the packet buffer 26, the protocol processing unit 41 DMA must be performed at least twice for each request to Pre-processing and post-processing are required to perform one DMA, and if the number of DMAs is large, it takes time to complete the transfer.

A first object of the present invention is to provide a method for transferring a file stored in a server machine to a client machine without moving the file in a main storage device in the server machine.

A second object of the present invention is to provide a file transfer method in which the number of DMAs from a main storage device to a network interface is small in a server device when transferring a file from a server device to a client device. It is.

[0014]

The server according to the present invention comprises a server program, a file system, a protocol processing unit, a buffer on a main storage, a secondary storage, and a network interface. The network interface has a packet buffer.

According to the file system of the present invention, when storing certain data as a file in the secondary storage device,
The data, which is the content of the file, is concatenated with a header required when the file is transferred later.

The file system according to the present invention may be arranged such that when the server program requests a file transfer, the contents linked to the header in the step are transferred to the buffer so as to be transferred to the buffer. Instruct,
When the transfer is completed, the protocol processing unit is called.
The called protocol processing unit writes the identification information of the file transfer destination in a portion corresponding to the header in the buffer, and instructs the network interface to transfer the contents of the buffer. Upon receiving the instruction, the network processing unit transfers the contents of the buffer to the packet buffer.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

(1) Hardware Configuration The hardware configuration of the present embodiment will be described with reference to FIG. The computer system 5 of the present embodiment includes a server 1, a client 2, and a network 3. The server machine 1 and the client machine 2 are connected to the network 3 by cables 4 respectively. Server machine 1
It has one or more processors and a main storage device, a network interface 11, and a secondary storage device 12. A program can be stored on the main storage device and executed by the processor.

The cable 4 is connected to the network interface 11, whereby the server 1 is connected to the network 3. Further, the network interface 11 has a storage device separately from the main storage device of the server 1, and a part thereof is secured as a packet buffer 26. The network interface 11 is assigned a unique network address (hereinafter abbreviated as “address”). The client machine 2 also has a network interface (not shown),
An address different from that of the network interface 11 is assigned.

Communication between the server machine 1 and the client machine 2 is realized as follows using this address.
That is, the transmitting side specifies the destination address and the area on the main storage device that stores the data to be transmitted,
By sending an instruction to the own network interface, the area on the main storage device is transmitted to the network 3 in the form of a packet, the destination address is received by the assigned network interface, and the receiving side specifies the destination address. The data is written to the area on the main storage device.

As described above, when a unique address is assigned to each network interface, by specifying the destination address by the transmission side, the data to be transmitted can be correctly delivered to the device having the network interface to which the specified address is assigned. For a more detailed explanation of the communication method that realizes the function "can be realized", see W. Richard Stevens, "UNIX Network Programming",
Prentice-Hall, pp. 171-196. In the computer system of the present embodiment, it is assumed that the communication method has been established, and further detailed description of the communication method will be omitted in this specification.

It should be noted that even when a server other than the server 1 is connected to the network 3 or when a client other than the client 2 is connected, or both, the respective server and client are connected. If a unique address is assigned to the network interface of the device, the method of this embodiment operates without any trouble by the communication method described in the above-mentioned document.

(2) Software Configuration The software configuration (executed programs and data) of the computer system 5 of this embodiment will be described with reference to FIG.

On the client machine 2, a client program 14 is executed. The client program 14 communicates with the server program 13 of the server machine 1 and requests to transfer a specific file. When the requested file is transferred from the server machine 1, it is received.

On the server machine 1, the server program 1
3 and the operating system 10 are stored on the main storage device and executed on the processor. The server program 13 receives the file transfer request received via the network 3, knows the address of the client machine 2 that has sent the request, and what file is requested, and executes the file transfer. Start. In some cases, the server program 13 checks whether the transfer of the file to the client machine 2 has no security problem.

The operating system 10 includes a server machine 1 such as a processor, a main storage device, and an external input / output device.
Manage the above computer resources. The management includes controlling the execution of the server program 13, securing the buffer 22 on the main memory, and controlling the secondary storage device 12 and the network interface 1.
1 includes sending an instruction to Operating system 1
0 includes the packet file system 20 and the protocol processing unit 21.

The packet file system 20 plays a role of managing the secondary storage device 12, similarly to the file system 40 in the prior art of FIG. That is, a function that allows the user of the server machine 1 to create, read, change, and delete a file on the secondary storage device 12 by dividing and accessing the secondary storage device 12 in file units is provided. Realize. How these functions are realized in the packet file system 20 will be described later. Note that the file handled by the packet file system 20 is hereinafter particularly referred to as a packet file to distinguish it from the file of the related art.

The packet file 20 has a file transfer function in addition to the functions described above. This function will also be described later. It should be noted that the packet file system 20 manages a part of the secondary storage device 12, and other parts of the secondary storage device 12 may be managed by a file different from the packet file system 20 in some cases. . Even in this case, the present embodiment operates without any trouble.

The packet file 23 is stored in the secondary storage device 12 under the management of the packet file system 20 described above. Although only one packet file is shown in FIG. 1, a plurality of packet files may actually be stored. The packet file system 20 can handle a plurality of packet files in the same manner as the file system 40 of the related art. The packet file 23 includes one or more headers 24
And data 25 (packet).

The protocol processing section 21 manages the network interface 11 similarly to the protocol processing section 41 in the prior art of FIG. The management includes creation of a header, an instruction to transfer data to the network interface 11, and the like. Thereby, the network 3
To communicate with other computers via.

The function of the protocol processing unit 21 will be described in detail. In order to realize communication between the server machine 1 and the client machine 2 via the network 3, the protocol processing unit 21 negotiates both the creation and transmission of the packet between the server program 13 and the client program 14. Must follow the protocol in place.
Therefore, the protocol processing unit 21 needs to create a packet in a format according to the protocol.

FIG. 3 shows the format of a packet in this embodiment. This format is based on the protocol described in the above-mentioned book by Stevens, but can be easily applied to packet formats defined by other protocols. FIG.
Is composed of a header 62 and data 67. The data 67 contains the contents of the file to be transferred. The header 62 includes a protocol type 63, a source address 64, a destination address 65,
It includes a checksum 66 and a data length 68, the format of which is defined by the protocol.

The header 62 allows the server machine 1 to correctly transfer the file contents via the network 3 to the client machine 2 which has transmitted the file transfer request. How to create the contents of the header in this embodiment will be described in the section describing the file transfer operation in this embodiment.

(3) Creation and Management of Packet File In this embodiment, a method of creating a file (packet file) handled by the packet file system 20 on the secondary storage device 12 will be described with reference to FIGS. Will be explained.

In FIG. 6, the server machine 1 executes a file creation program 120 (for example, an editor, a drawing tool, a word processor, etc.) under the management of the operating system 10. File creation program 12
Reference numeral 0 indicates that the user buffer 121 is reserved in the main storage device, and the contents to be stored as the packet file 23 in the secondary storage device 12 are written in the user buffer 121.
When the writing to the user buffer 121 is completed, the file creation program 120 requests the operating system 10 to store the contents of the user buffer 121 in the secondary storage device 12 as a packet file. The operating system 10 that has received the request transfers the request to the packet file system 20, which is a file system that manages the secondary storage device 12. In response to the transferred request, the packet file system 20
Stores the contents of the user buffer 121 in the data buffer 12
Copy to 3. The data buffer 123 is an area secured by the packet file system 20 in the main storage device of the server machine 1.

Next, the packet file system 20 creates a packet according to the procedure shown in FIG. 4 without writing the content copied to the data buffer 123 as it is to the secondary storage device. The data buffer 123 stores the contents (new file) 42 for which a new file is to be created in FIG. The packet file system 20 first converts the new file 80 into one or more data 81 according to the maximum packet length (MTU) that can be transmitted to the network 3.
A, 81B,... Since the MTU is determined by the network 3 connecting the server 1 and the client 2, the number of pieces of data of the new file 80 is determined only by the length of the new file 80. In FIG.
The new file 80 has three data 81A, 81B, 81
C is divided into three.

Next, the packet file system 20
One header 82A to 82C is created for each of the data 81A to 81C. These headers are created on the header buffer 122 (FIG. 6) which is an area secured on the main storage by the packet file system 20. These headers have the same size as the header 62 in FIG.

For each of the created headers 82A to 82C, the packet file system 20 adds data 81A to a portion corresponding to the data length 68 (FIG. 3).
Write the length of ~ 81C. In the other portions of the headers 82A to 82C, values (for example, 0) indicating blanks are written.

When the writing to the headers 82A to 82C is completed, the packet file system 20
And one or both of the data 81A and the data 81A by copying them in the main storage device of the server machine 1, and
Create A. The packet is created in the data buffer 12
3, a new area may be secured in the main storage device, or either of the header buffers 122 may be used. Further, the packet file system 20 performs the same operation,
Combination of header 82B and data 81B, header 82
This is also performed for the combination of C and data 81C to create packets 83B and 83C, respectively.

When the creation of the packets 83A to 83C is completed, the packet file system 20 writes the created packets 83A to 83C in the secondary storage device 12 as the packet file 23. FIG. 5 shows the format of the packet file 23 written in the secondary storage device 12. Thus, the creation of the packet file 23 is completed, and the packet file system 20 notifies the file creation program 120 that the writing has been completed.

After the creation of the packet file 23, when another program requests the operating system 10 to read the packet file 23 (for the purpose of file editing or the like), the packet file system 20 executes the above procedure in reverse. Then, only the data 81A to 81C are extracted from the packet file 23, and the data 81A to 81C are linked and copied to an area on the main storage designated by the program.

From the above, it is apparent that the packet file system 20 of this embodiment has the following advantages. That is, the packet file 23 of the present embodiment can be handled in exactly the same manner as the file 42 of the related art from the file creation program executed on the server machine 1. Therefore, the packet file 23 can be used for creation and editing without changing an existing program such as a word processor or a drawing tool.

(4) File Transfer The operation at the time of file transfer in this embodiment is shown in FIG.
This will be described with reference to FIG. The packet file 23 in the secondary storage device 12 is a file created by the packet file system 20 by the method described above.

When the client program 14 running on the client machine 2 requests transfer of the file (packet file) 23, the request is received by the server program 13. The server program 13 that has received the request knows which file is being requested and the address of the client machine 2 that made the request from the contents of the request.
The requested file (packet file) 23 is
Requests transfer to client machine 2.

A specified file (packet file)
Since 23 is stored in the secondary storage device 12, the request received by the operating system 10 is transferred to the packet file system 20. Upon receiving the request, the packet file system 20 instructs the secondary storage device 12 to transfer the contents of the specified packet file 23 to the buffer 22. When the transfer is completed, the contents of the packet file 23 shown in FIG.

Next, the packet file system 20 calls the protocol processing unit 21 and requests the contents of the buffer 22 to be transmitted to the client machine 2.
Upon receiving the request, the protocol processing unit 21 transmits the packets 83A to 83 of the packet file 23 stored in the buffer 22.
A blank portion is written for each header of 3C as follows.

First, the protocol type 63 (FIG. 3) includes:
Write the identification number of the protocol to be sent. Since the protocol is known at the latest when the server program 13 receives the request from the client program 14, the corresponding identification number can be written at the time of file transfer. Next, the source address 64
In the field, the address of the network interface 11 of the server machine 1 is written. Further, the address of the client machine 2 is written in the transmission destination address 65. Further, the checksum of the packet is calculated and written to the checksum 66. In addition, information (defined by the protocol) is written in the header.

When the destination address or the like is written in the blank of the header, each of the packets 83A to 83C of the packet file 23 stored in the buffer 22 is immediately ready for sequential transfer to the packet buffer of the network interface 11 by DMA. Has become. Thereafter, the protocol processing unit 21 instructs the network interface 11 to sequentially transmit the packets 83A to 83C.
The procedure at this time is the same as that of the protocol processing unit 41 in the related art after the creation of the header is completed.

The above is the file transfer operation in this embodiment. From the above description, it is apparent that the file transfer method in the present embodiment has the following features.

First, in the file transfer according to the present embodiment, the server program 13 merely needs to instruct the execution of the file transfer, and it is necessary to secure the user buffer in the main memory and to first read the user buffer. Since there is no data transfer, no data is moved on the main memory at the time of file transfer. Therefore, the file can be transferred at a higher speed than the conventional file transfer.

Second, in the file transfer according to the present embodiment, since the header and data of one packet are continuous on the main memory from the beginning, the network interface of the main memory required for transmission of one packet is used. The number of DMAs with the 11 packet buffers 26 is only one. Therefore, the file can be transferred at a higher speed as compared with the conventional file transfer.

Third, when a packet is transmitted from the server machine 1 to the network 3, the packet has a format according to a predetermined protocol. Therefore, it is not necessary to change the client machine 2 and the client program 14 in performing the file transfer according to the present embodiment, and the existing computer and program can be used.

[0053]

According to the present invention, data transfer on the main storage does not occur at all during file transfer. Therefore,
The file can be transferred faster than the conventional file transfer.

Further, according to the present invention, the number of DMAs between the main storage device and the network interface required for transmitting one packet in the file transfer is only one. Therefore, the file can be transferred at a higher speed as compared with the conventional file transfer.

[Brief description of the drawings]

FIG. 1 is a diagram showing an operation of file transfer according to an embodiment of the present invention.

FIG. 2 is a diagram showing a file transfer operation according to a conventional technique.

FIG. 3 is a diagram showing a packet format according to an embodiment of the present invention.

FIG. 4 is a diagram showing a procedure for creating a packet file from data to be converted into a file in one embodiment of the present invention.

FIG. 5 is a diagram showing a format of a packet file according to an embodiment of the present invention.

FIG. 6 is a diagram showing an operation when creating a packet file in one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Server machine, 2 ... Client machine, 3 ... Network, 10 ... Operating system, 11 ... Network interface, 12 ... Secondary storage device, 20 ... Packet file system, 23 ... Packet file, 81
A to 81C: data, 82A to 82C: header, 83A
８３83C: packet.

Claims (6)

[Claims] 1. A file system for managing files stored in a secondary storage device, wherein when a user writes a file in the secondary storage device, the content of the file flows over a network. A file system having a step of writing in the form of a packet in the secondary storage device. 2. The step of writing the contents of a file into a secondary storage device in the form of a packet flowing through a network, wherein the maximum transfer length (MT) of a packet determined by a network connected to a computer having the secondary storage device.
U) dividing the contents of the file into a plurality of data in accordance with U), creating one header for each of the plurality of data, and generating the header generated for each of the plurality of data. 2. The file system according to claim 1, further comprising the steps of: creating a plurality of packets by linking the plurality of packets; and storing the plurality of packets in the secondary storage device. 3. The step of dividing the content of the file into a plurality of data in accordance with the MTU.
U as an MTU defined by a protocol available in the network, and creating a header for each of the plurality of data,
3. The file system according to claim 2, further comprising a step of setting a format of the header according to a protocol defined by a protocol available in the network. 4. The method according to claim 1, further comprising the step of: when the user program reads a file, extracting only the data portion from the file stored in the secondary storage device in the form of the packet. The file system according to claim 3. 5. A method of transferring a file stored in a secondary storage device of a first computer to a second computer, wherein the file system manages the file. A file transfer method, wherein the file system according to any one of the above is used. 6. The file transfer method according to claim 5, wherein a step of securing a buffer on a main storage device of said first computer, and a step of transferring a file stored in said secondary storage device to said buffer. 6. The file transfer method according to claim 5, further comprising the steps of: (a) writing the address of the second computer into a portion corresponding to the header of the file read into the buffer;