JP5077624B2 - USB device sharing system, server interface device used therefor, and operation method thereof - Google Patents

Description

  The present invention relates to a USB device sharing system in which a plurality of servers are connected to a USB device via a common USB bus, a server interface device used in the server, an operation method thereof, an operation program thereof, and a device sharing system. The present invention relates to a USB device sharing method in which a plurality of servers have a data cache function of a USB device and the USB device can be used simultaneously.

  In an apparatus in which a plurality of servers are mounted on a single chassis such as a blade server, each server has a CD-ROM (Compact Disk Read Only Memory) drive, a floppy (registered trademark) disk drive (hereinafter referred to as FDD), etc. When peripheral devices are mounted, there are problems in terms of mounting area and cost. For this reason, a system has been adopted in which each peripheral device is mounted on the chassis one by one and a server that uses the peripheral device is switched by a switch so that a plurality of servers do not use the peripheral device at the same time.

  As an interface for connecting a server and peripheral devices, USB (Universal Serial Bus), which is most popular at present and is advantageous in terms of cost and assortment of devices, is usually used. In server applications, peripheral devices are mainly used for installing software such as an OS (operating system) and are rarely used during operation.

As a prior art related to the present invention, there is a parallel digital signal processing device (see Patent Document 1) that shortens the time required for data transfer, and a storage system (see Patent Document 2) that adopts a common bus system. Proposed.
Japanese Patent Laid-Open No. 04-138554 Japanese Patent No. 3264465

  However, in the apparatus for switching servers that use peripheral devices as described above, software must be installed one by one in turn, which requires a lot of labor and time especially when the number of servers increases. . The prior art described above has not necessarily been made by recognizing such a problem.

  The present invention has been made in consideration of such a conventional situation, and in a system in which a plurality of servers use the same peripheral device, data transfer time such as software installation of all servers regardless of the number of servers. The purpose is to reduce the time and labor of operation significantly.

In order to achieve the above object, a USB device sharing system according to the present invention includes a plurality of servers, and the plurality of servers are connected to a USB device via a common USB bus. A USB controller that transmits and receives packets to and from the USB device; and an interface unit disposed between the USB controller and the USB bus, wherein the interface unit analyzes the contents of the packet flowing through the USB bus. First packet analysis means that performs data capture, and data capture means that captures, into a buffer, data read and written between the plurality of servers and the USB device in accordance with the analysis result of the packet by the first packet analysis means And monitoring packets flowing through the USB bus, and other servers Bus monitoring means for suppressing output of packets to the USB bus while it can be determined that the USB bus is being used; temporary storage means for temporarily saving packets output from the USB controller to the USB device; Analyzing a device request output from the USB controller to the USB device and generating a read address of the buffer from address information in the device request; and the second packet analyzing unit A determination unit that reads the buffer based on a read address of the buffer that is an analysis result and determines whether or not the same data as the data to be read from the USB device exists in the buffer; When the same data exists, Device without outputting the packet unit to the USB bus, and a packet output control means for returning the same data to the USB controller from said buffer, said first packet analysis means, through said USB bus The buffer write address is generated from the address information of the request, the data fetching means fetches data flowing through the USB bus into the buffer based on the buffer write address, and the second packet analyzing means When a device request for data read to the USB device is issued from the USB controller, the read address of the buffer is generated from the address information of the device request, and the determination unit is configured to generate the buffer based on the read address of the buffer. The packet output control means includes a handshake generation unit for generating a handshake packet for output to the USB controller, the handshake generation unit, the USB bus, and And a multiplexer that selectively switches the output side of the buffer and connects to the USB controller side .

  According to the present invention, in a system in which a plurality of servers use the same peripheral device, data transfer time such as software installation of all servers is greatly reduced regardless of the number of servers, and operation time and effort are reduced. can do.

  Next, a USB device sharing system according to the present invention, a server interface apparatus used therewith, and a best mode for carrying out the operation method will be described in detail with reference to the drawings.

  Referring to FIG. 1, a block diagram of a USB device sharing system as an embodiment of the present invention is shown.

  In the figure, the server A 100 and the server B 200 have exactly the same hardware configuration, and are connected to a USB HUB (USB hub) 2 via the USB bus 1. The USB HUB 2 is connected to the CD-ROM drive 3 and the FDD drive 4 which are USB devices, and is shared by the server A 100 and the server B 200 via the USB bus 1 and the USB HUB 2.

  The server A 100 includes a USB controller 102 and an interface unit 101 (which constitutes the interface means or apparatus of the present invention) provided between the USB controller 102 and the USB bus 1. Note that the USB controller 102 and the interface unit 101 can be configured as either an integrated device or a separate device as long as the respective functions can be realized.

  The interface unit 101 includes a multiplexer 104, an output packet analysis unit 105, an output packet temporary save FIFO (First in First out) (FIFO buffer) 106, a handshake generation unit 107, a packet output determination unit 108, a data buffer 110, and an input request analysis unit. 111 and a USB bus monitoring unit 112. At least some of the functions of these units can be realized by program code executed by a processor (for example, a CPU (Central Processing Unit)). In this case, a processor and program code are included as components.

  The device request output from the USB controller 102 is received by the output packet analysis unit 105 and the output packet temporary save FIFO 106.

  The output packet analysis unit 105 analyzes the device request output from the USB controller 102 and generates the read address of the data buffer 110 from the address information in the device request. Also, the device request output from the USB controller 102 and the type of token packet are reported to the packet output determination unit 108.

  The output packet temporary save FIFO 106 temporarily stores the packet output from the USB controller 102 and performs either processing of outputting the packet to the USB bus 1 or discarding it according to an instruction from the packet output determination unit 108. Do.

  The packet output determination unit 108 is stored in the output packet temporary save FIFO 106 based on the packet information received from the output packet analysis unit 105, the data storage status of the data buffer 110, and the USB bus usage status received from the USB bus monitoring unit 112. It is determined whether to output the packet to the USB bus 1, which direction the multiplexer 104 is switched to, and which handshake the handshake generation unit 107 generates, and an instruction is given according to the situation. put out.

  The USB bus monitoring unit 112 monitors whether the USB bus 1 is in use, and notifies the packet output determination unit 108 of the usage status of the USB bus 1.

  The input request analysis unit 111 analyzes a device request flowing through the USB bus 1 and generates a write address of the data buffer 110 from address information in the device request.

  The data buffer 110 writes the data packet flowing through the USB bus 1 to the address specified by the input packet analysis unit 111, and outputs the data at the address specified by the output packet analysis unit 105 to the multiplexer 104. Further, it reports to the packet output determination unit 108 whether data is stored at the address designated by the output packet analysis unit 105.

  The handshake generation unit 107 generates an ACK or NACK handshake packet in accordance with an instruction from the packet output determination unit 108.

  In response to an instruction from the packet output determination unit 108, the multiplexer 104 sends the packet input from the USB bus 1, the data packet output from the data buffer 110, or the handshake packet generated by the handshake generation unit 107 to the USB controller 102. Select the packet to be output.

  The server B 200 has the same configuration as the server A 100 described above, and includes a USB controller 202 and an interface unit 201. The interface unit 201 includes a multiplexer 204, an output packet analysis unit 205, an output packet temporary save FIFO 206, a handshake generation unit 207, a packet output determination unit 208, a data buffer 210, an input request analysis unit 211, and a USB bus monitoring unit 212. Since the function of each part is the same as the function of each part of the server A100, description thereof is omitted.

Next, the operation of the circuit of FIG. 1 will be described with reference to FIGS. 2 to 4 show the processing operation of the packet output determining unit 108.
(When reading data)
First, an operation when data is read from a USB device will be described with reference to FIG.

  First, when the server A 100 reads data from the CD-ROM drive 3, the USB controller 102 first issues a device request. The device request is composed of a token packet and a data packet. The device request output from the USB controller 102 is stored in the packet temporary save FIFO 106 and simultaneously received by the output packet analysis unit 105.

  The output packet analysis unit 105 analyzes the received device request, generates the read address of the data buffer 110 from the address information in the device request, and at the same time, issues the data read device request to the packet output determination unit 108 To be notified. The data buffer 110 notifies the packet output determination unit 108 whether or not data corresponding to the read address generated by the output packet analysis unit 105 is stored. Here, the processing is divided between the case where data is not stored in the data buffer 110 and the case where data is already stored.

  When data is not stored in the data buffer 110, the packet output determination unit 108 determines that the device is based on two conditions: a data read device request is issued and data is not stored in the data buffer 110. The request is output to the USB bus 1, and it is determined that the handshake packet for the output device request is returned from the CD-ROM drive (step St1: YES, step St2: NO). Based on the determination result, the packet output determination unit 108 instructs the device request stored in the temporary packet save FIFO 106 to be output to the USB bus 1, and switches the multiplexer 104 to the USB bus 1 side (step St3). The device request output to the USB bus 1 is received by the server A100, the server B200, and the USB HUB2.

  The input packet analysis units 111 and 211 of the server A 100 and the server B 200 analyze the received device request, and generate the write addresses of the data buffers 110 and 210 from the address information in the device request. The USB HUB 2 outputs the received device request to the CD-ROM 3, and the CD-ROM 3 outputs an ACK handshake packet because it has received the device request. The output ACK handshake packet is output to the USB bus 1 via the USB HUB 2 and received by the server A 100 and the server B 200.

  In the server A100, since the multiplexer 104 faces the USB bus 1, the ACK handshake packet is output to the USB controller 102. The server B 200 discards the ACK handshake packet because the multiplexer 204 does not face the USB bus 1 side.

  Upon receiving the ACK handshake packet, the USB controller 102 of the server A 100 recognizes that the CD-ROM drive 3 is ready to output a data packet, and outputs an IN token packet. The output IN token packet is received by the output packet analysis unit 105 and the output packet temporary save FIFO 106, and the output packet analysis unit 105 reports to the packet output determination unit 108 that the IN token packet has been issued.

  When receiving the IN token packet issuance report (step St4: YES), the packet output determining unit 108 instructs the output packet temporary save FIFO 106 to output the IN token packet to the USB bus 1, and is further returned from the CD-ROM 3. The multiplexer 104 is switched to the USB bus 1 side so that the USB controller 102 can receive the data packet to be received (step St5). The IN token packet output to the USB bus 1 is received by the CD-ROM drive 3 via the USB HUB, and the CD-ROM drive 3 thereby outputs a data packet. The data packet is output to the USB bus 1 via the USB HUB 2 and received by the server A 100 and the server B 200.

  The data buffers 110 and 210 of the server A 100 and the server B 200 store data packets at addresses designated by the input packet analysis units 111 and 211. In the server A100, since the multiplexer 104 faces the USB bus 1, the data packet is stored in the buffer 110 and output to the USB controller 102.

  When the USB controller 102 receives all the data packets, the USB controller 102 outputs an ACK handshake packet. The output ACK handshake is transferred to the CD-ROM drive 3 in the same procedure as the IN token, and the data read from the CD-ROM drive 3 is completed. At this time, the data of the CD-ROM drive 3 is stored in the data buffers 110 and 210 of the server A100 and the server B200.

  When data is stored in the data buffer 110, the packet output determination unit 108 determines that a data read device request is issued and that a data packet is stored in the data buffer 110. It is determined not to output the device request to the USB bus 1 but to output the data packet stored in the data buffer 110 to the USB controller 102 (step St1: YES, step St2: YES). Based on the determination result, the packet output determination unit 108 discards the device request stored in the packet temporary save FIFO 106, instructs the handshake generation unit 107 to generate an ACK handshake packet, and causes the multiplexer 104 to the handshake generation unit 107 side. (Step St6). The generated ACK handshake packet is output to the USB controller 102 via the multiplexer 104.

  The USB controller 102 recognizes that the CD-ROM drive 3 is ready to output data by receiving the handshake packet, and outputs an IN token packet. The output IN token packet is received by the output packet analysis unit 105 and the output packet temporary save FIFO 106, and the output packet analysis unit 105 reports to the packet output determination unit 108 that the IN token packet has been issued.

  When receiving the report of the IN token packet issuance (step St7: YES), the packet output determining unit 108 instructs the output packet temporary save FIFO 106 to discard the IN token packet, and switches the multiplexer 104 to the data buffer 110 side (step). St8). The data packet output from the data buffer 110 is output to the USB controller 102 via the multiplexer 104 and simultaneously monitored by the packet output determination unit 108.

Subsequently, when all the data packets are output (step St9: YES), the packet output determination unit 108 instructs the handshake generation unit 107 to generate an ACK handshake packet, and switches the multiplexer 104 to the handshake generation unit 107 side. (Step St10). The USB controller 102 receives the generated ACK handshake, and the data read is completed. As described above, when data is already stored in the data buffer 110, no packet flows on the USB bus 1.
(When writing data)
Next, an operation when data is written to the USB device will be described with reference to FIG.

  When the server A100 writes data to the FDD drive 4, the USB controller 102 first issues a device request. The device request output from the USB controller 102 is stored in the packet temporary save FIFO 106 and simultaneously received by the output packet analysis unit 105. The output packet analysis unit 105 analyzes the received device request and notifies the packet output determination unit 108 that a data write device request has been issued.

  Since the device request for data write has been issued, the packet output determining unit 108 outputs the device request to the USB bus 1, and determines that the handshake packet for the output device request is returned from the FDD drive 3 (step St11: YES).

  Based on the determination result, the packet output determination unit 108 instructs the temporary packet save FIFO 106 to output the stored device request to the USB bus 1 and switches the multiplexer 104 to the USB bus 1 side (step St12). The device request output to the USB bus 1 is received by the server A100, the server B200, and the USB HUB2.

  The input packet analysis units 111 and 211 of the server A 100 and the server B 200 analyze the received device request and generate the write addresses of the data buffers 110 and 210. The USB HUB 2 outputs a device request to the FDD drive 4, and since the FDD drive 4 has received the device request, it outputs an ACK handshake packet. The output handshake packet is output to the USB bus 1 via the USB HUB 2 and received by the server A 100 and the server B 200.

  In the server A100, since the multiplexer 104 faces the USB bus 1, the handshake packet is output to the USB controller 102. The server B 200 discards the handshake packet because the multiplexer 204 does not face the USB bus 1 side.

  The USB controller 102 of the server A 100 receives the handshake packet, determines that the FDD drive 4 is ready to receive data, and outputs an OUT token packet and a data packet. The output OUT token packet is received by the output packet analysis unit 105 and the output packet temporary save FIFO 106, and the output packet analysis unit 105 reports to the packet output determination unit 108 that the OUT token packet has been issued.

  When receiving the report of the OUT token packet issuance (step St13: YES), the packet output determining unit 108 outputs the OUT token packet to the output packet temporary save FIFO 106 and the data packet output from the USB controller 102 to the USB bus 1 thereafter. (Step St14). The server A 100, the server B 200, and the USB HUB 2 receive the OUT token packet and the data packet output to the USB bus 1.

  The USB HUB 2 transfers the received packet to the FDD drive 4. The OUT token packet received by the server A 100 and the server B 200 is discarded, and the data packet is stored in the data buffers 110 and 210. At this time, the addresses to be stored are those generated by the input packet analysis units 111 and 211 from the device request.

  While the USB controller 102 outputs the data packet, the packet output determination unit 108 monitors the completion of the data packet transfer (step St15). When the transfer of the data packet is completed (step St15: YES), the packet output determination unit 108 switches the multiplexer 104 to the USB bus 1 side so that the USB controller 102 can receive the handshake packet output from the FDD drive 4. (Step St16).

  When all the data packets are received, the FDD drive 4 outputs an ACK handshake packet. The output ACK handshake packet is output to the USB bus 1 via the USB HUB 2 and received by the server A 100 and the server B 200.

In the server A100, since the multiplexer 104 faces the USB bus 1, the ACK handshake packet is output to the USB controller 102. In server B200, it is discarded. In this way, when the USB controller 102 writes data to the USB device, the contents of the data buffers 110 and 210 are also updated, so that data consistency is maintained.
(When other server is using USB bus)
Finally, with reference to FIG. 4, the operation when the USB bus is used by another server will be described.

  When the server B 200 uses the USB bus 1, the token packet first flows on the USB bus 1, and finally the handshake packet flows on the USB bus 1. The USB bus monitoring unit 112 of the server A 100 instructs the packet output determination unit 108 to suppress the packet output to the USB bus 1 until the handshake packet flows after the token packet flows to the USB bus 1.

  When the USB controller 102 tries to output a packet while the USB bus monitoring unit 112 is instructed to suppress the packet output (step St21: YES), the packet output determination unit 108 proceeds to the output packet temporary save FIFO 106. Is instructed to generate the NACK handshake packet to the handshake generation unit 107, the multiplexer 104 is switched to the handshake 107 side, and the NACK handshake packet is output to the USB controller 102 (step St22).

  Since the USB controller 102 has received the NACK handshake packet, the USB controller 102 performs a retry process.

  As described above, in this embodiment, when the server A 100 acquires data from the CD-ROM drive 3, the device request issued by the USB controller 102 is input to the input packet analysis units 111 and 211 of the server A 100 and the server B 200, respectively. Is generated, and the write addresses of the data buffers 110 and 210 are generated from the address information in the request. When a response to the device request is returned from the CD-ROM drive 3, the response content from the CD-ROM drive 3 is recorded in the data buffers 110 and 210. When the server B 200 acquires data for the same address, the output packet analysis unit 205 analyzes the device request issued by the USB controller 202, generates the read address of the data buffer 210 from the address information in the request, and stores the data. read out.

  Thus, in this embodiment, the contents of the USB device are buffered in each server, so that each server can use the USB device at the same time. Also, by caching the USB device data in each server, the overhead due to server switching is reduced, and the USB bus usage efficiency is improved, so the software installation time for all servers can be greatly reduced. It becomes possible. In addition, since the switch operation for switching the servers is not necessary, the operation time can be reduced.

  Therefore, according to the present embodiment, in a device in which a plurality of servers serving as a host share a USB device, the host device can have a USB device data cache function so that a plurality of hosts can use the USB device simultaneously.

  As described above, according to the present embodiment, the following effects can be obtained.

  The first effect is that when data is cached in each server, the data transfer is completed without using the USB bus, so that the USB bus can be used effectively.

  The second effect is that since each server caches the data of the USB device, the USB device can be shared without switching the server.

  The third effect is that since the USB device can be shared without switching the server, the operation time can be reduced.

  In the present embodiment, an example in which a USB device is shared by two servers A100 and B200 has been shown. However, three interface units 301,..., N01 similar to the interface units 101 and 201 as shown in FIG. If the servers C300,..., And the server n00 are connected between the USB controllers 301,..., N01 and the USB bus 1, the USB bus common to the three or more servers 100, 200, 300,. USB devices (CD-ROM drive 3 and FDD drive 4) can be shared via 1. Even in this case, the same effect as described above can be obtained.

  In this embodiment, a case where a plurality of servers share a USB device via a common USB bus has been described. However, a plurality of servers can connect peripheral devices other than the USB device via a common bus other than the USB bus. It is applicable even when sharing.

  As mentioned above, although the Example of this invention was described in detail, this invention is not limited to the above-mentioned Example illustrated typically, and those skilled in the art will be based on description content of a claim. The present invention can be modified and changed into various modes without departing from the gist of the present invention. These modified examples and modified examples also belong to the scope of the right of the present invention.

  Further, in the case where at least a part of functions of each unit constituting the USB device sharing system according to the present embodiment is realized using a program code, the program code and a recording medium for recording the program code are included in the scope of the present invention. It is. The program code in this case includes those program codes when the above functions are realized in cooperation with an operating system or other application software. As a recording medium, a hard disk, a ROM (Read Only Memory), a flexible disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, and the like can be used.

  The present invention can also be applied to a device such as a blade server in which a plurality of servers are mounted on a single chassis.

1 is a block diagram illustrating an overall configuration of a USB device sharing system according to an embodiment of the present invention. In the Example of this invention, it is a flowchart which shows the process of the packet output control part at the time of data read. In the Example of this invention, it is a flowchart which shows the process of the packet output control part at the time of data write. In the Example of this invention, it is a flowchart which shows the process of the packet output control part when another server is using the USB bus. It is a schematic block diagram which shows the whole structure of a USB device sharing system at the time of applying the Example of this invention to three or more servers.

Explanation of symbols

1 USB bus 2 USB HUB
3 CD-ROM drive 4 FDD drive 100, 200 Server A, B
101, 201 Interface unit 102, 202 USB controller 104, 204 Multiplexer 105, 205 Output packet analysis unit 106, 206 Output packet temporary save FIFO
107, 207 Handshake generation unit 108, 208 Packet output determination unit 110, 210 Data buffer 111, 211 Input packet analysis unit 112, 212 USB bus monitoring unit

Claims (5)

In a system having a plurality of servers, wherein the plurality of servers are connected to a USB device via a common USB bus,
The plurality of servers are:
A USB controller that transmits and receives packets to and from the USB device;
An interface means arranged between the USB controller and the USB bus,
The interface means includes
First packet analysis means for analyzing the content of a packet flowing through the USB bus;
Data fetching means for fetching into the buffer data read and written between the plurality of servers and the USB device according to the analysis result of the packet by the first packet analyzing means;
A bus monitoring unit that monitors packets flowing through the USB bus and suppresses output of packets to the USB bus while it can be determined that another server is using the USB bus;
Temporary storage means for temporarily storing packets output from the USB controller to the USB device;
A second packet analyzing means for analyzing a device request output from the USB controller to the USB device, and generating a read address of the buffer from address information in the device request;
The buffer is read based on the read address of the buffer, which is the analysis result by the second packet analysis means, and it is determined whether or not the same data as the data to be read from the USB device exists in the buffer. A judgment means to
Packet output control means for returning the same data from the buffer to the USB controller without outputting the packet of the temporary storage means to the USB bus when the same data exists in the buffer;
The first packet analysis means generates a write address of the buffer from address information of a device request flowing through the USB bus,
The data capture means captures data flowing through the USB bus based on the write address of the buffer into the buffer,
The second packet analyzing means generates a read address of the buffer from address information of the device request when a device request for data read to the USB device is issued from the USB controller,
The determining means determines whether the same data exists in the buffer based on a read address of the buffer;
The packet output control means includes
A handshake generator for generating a handshake packet for output to the USB controller;
The handshake generation unit, the USB bus, and U SB device sharing system that, comprising a multiplexer that connects to the USB controller side output selectively switching of said buffer. The packet output control means includes
When the same data corresponding to the data read exists in the buffer when a device request for data read is issued from the USB controller, a control command is given to the temporary storage unit to discard the device request, A control command is given to the handshake generator to generate an ACK handshake packet for the device request, and a control command is given to the multiplexer to output the ACK handshake packet generated by the handshake generator to the USB controller Means,
When an IN token packet is issued from the USB controller in response to the ACK handshake packet, a control command is given to the temporary storage unit so as to discard the IN token packet, and from the buffer to the USB controller Means for providing a control command to the multiplexer to output data;
The multiplexer gives a control command to the handshake generation unit so as to generate an ACK handshake packet after the same data is output, and outputs the ACK handshake packet generated by the handshake generation unit to the USB controller USB device sharing system according to claim 1, further comprising a means for providing a control command to. The packet output control means includes
When the device request for data read is issued from the USB controller, the temporary storage means controls to output the device request to the USB bus when the same data corresponding to the data read does not exist in the buffer Means for giving a control command to the multiplexer so as to output an ACK handshake packet sent from the USB device via the USB bus to the USB controller in response to the device request;
When an IN token packet is issued from the USB controller in response to the ACK handshake packet, a control command is given to the temporary storage unit so that the IN token packet is output to the USB bus, and the response to the IN token packet 3. The USB device according to claim 2 , further comprising means for giving a control command to the multiplexer so as to output a data packet sent from the USB device via the USB bus to the USB controller. Shared system. The packet output control means includes
When a device request for data write by the USB controller is issued, a control command is given to the temporary storage unit to output the device request to the USB bus, and the USB device responds to the device request from the USB device. Means for giving a control command to the multiplexer so as to output an ACK handshake packet sent via the bus to the USB controller;
When a OUT token packet is issued from the USB controller in response to the ACK handshake packet, a control command is given to the temporary storage unit so that the OUT token packet and a data packet corresponding to the OUT token packet are output to the USB bus. ,
And a means for giving a control command to the multiplexer so as to output an ACK handshake packet sent from the USB device via the USB bus to the USB controller when transfer of the data packet is completed. The USB device sharing system according to any one of claims 1 to 3 . The packet output control means includes
Instructs the temporary storage means to discard the packet when a packet is output from the USB controller while the USB bus is being used by another server, and generates a NACK handshake packet for the device request Means for giving a control command to the handshake generation unit and giving a control command to the multiplexer so as to output the NACK handshake packet generated by the handshake generation unit to the USB controller. The USB device sharing system according to any one of claims 1 to 4 .

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