JP2006031123A - Usb memory device and usb memory device control program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a USB memory device whose capacity is increased by connecting two or more USB memories together, whose data is accessed at high speed, and whose stored data is easily secured, and also to provide a USB memory device control program for controlling the USB memory device. <P>SOLUTION: This USB memory device is provided with a distributed storage means 20 for making respective memories 7 of a USB memory device A1 and other USB memory devices A2 and A3 connected through primary and secondary USB interfaces 4 and 6 in a row, store data inputted from a host unit by distributing the input data by every predetermined unit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides a USB interface connectable to a USB interface of a host device, writing means for writing data input from the host device via the USB interface to a memory, a memory, and reading data stored in the memory. The present invention relates to a USB memory device including a reading unit that outputs to a host device via the USB interface.

  In recent years, USB has been widely used as a data transmission standard between a computer and peripheral devices. Since USB can connect a plurality of slave devices in a daisy chain to a single USB interface provided in a computer, the host device can advantageously control a large number of peripheral devices with a small number of interfaces. It has special features.

  That is, a slave device that supports USB is provided with both a primary USB interface that can be connected to a USB interface of a host device such as a computer and a secondary USB interface that can be connected to the primary USB interface of another slave device. By connecting the primary USB interface of another slave device to the secondary USB interface, it is possible to connect multiple slave devices in a daisy chain and connect multiple slave devices to one USB interface of the host device. It has become.

  Now, with the popularization of USB interfaces in general computers, USB memory devices (generally also simply referred to as “USB memories”) have become widespread as auxiliary storage devices for computers.

The USB memory device includes a primary USB interface and a flash memory capable of storing data.
The primary USB interface is connected to the USB interface of a host device such as a computer or the secondary USB interface of another slave device connected in a daisy chain from the USB interface of the host device, and between the host device and the USB memory device. Enables data input / output.
A USB memory device connected to the host device via the primary USB interface behaves as one of the slave devices. The USB memory device can write data input from the host device via the primary USB interface to the flash memory, and can output data stored in the flash memory to the host device via the primary USB interface. The data can be read and written by the host device.

One aspect of a conventional USB memory device is disclosed in Patent Document 1. The USB memory device described in Patent Document 1 includes a secondary USB interface that can be connected to the primary USB interface of another USB memory device, in addition to the primary USB interface that can be connected to the USB interface of the host device. Thus, a plurality of USB memory devices are provided so as to be connected in a daisy chain from the USB interface of the host device (Patent Document 1, paragraph 0048).
Then, files are copied between USB memory devices connected in series (in a daisy chain), or a plurality of USB memory devices are recognized as an integrated device, and a data capacity is selected based on the number of connected USB memory devices. (Patent Document 1, paragraphs 0050-0052).

JP 2002-41247 A (paragraphs 0048, 0050-0052)

A conventional USB memory device such as the USB memory device described in Patent Document 1 has a problem that data access (read / write) speed is low.
As a memory of a USB memory device, a flash memory is generally used. However, a writing speed and a reading speed of the flash memory are generally slower than a communication speed of 480 Mbps of USB 2.0 which is currently popular, It takes a lot of time for writing and reading.

Further, the conventional USB memory device has a problem that it takes time to ensure the security of stored data.
That is, in the conventional USB memory device, in order to prevent the stored data from being read by a third party, it is necessary to separately perform processing such as encryption, which takes time and effort.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to increase the capacity by connecting a plurality of connections, perform high-speed data access, and easily secure the security of stored data. It is to provide a USB memory device that can be used and a USB memory device control program for controlling the USB memory device.

  The inventor of the present application is a control program for a plurality of USB memory devices or a plurality of USB memory devices connected in a daisy chain using a distributed storage technique in which one data is divided into a plurality of storage devices and written in parallel (simultaneously), such as RAID in a hard disk. By applying to, we succeeded in solving the above problems.

In order to solve the above problems, a USB memory device according to the present invention has the following configuration. That is, a primary USB that can be connected to the USB interface of the host device or the USB interface of another slave device connected in a daisy chain from the USB interface of the host device and that can input and output data with the host device. A secondary USB interface that is connectable to an interface and a USB interface of another slave device and is capable of inputting / outputting data to / from the other slave device; a memory capable of storing data; and the primary USB Writing means for storing data input from the host device via the interface in the memory; and reading means for reading data stored in the memory and outputting the data to the host device via the primary USB interface; USB memory device with Performs control to store data input from the host device in a distributed manner in units of the USB memory device and other USB memory devices connected in a daisy chain via the primary and secondary USB interfaces. A distributed storage means is provided.
According to this, since the data is distributed and stored in the memories of the plurality of USB memory devices by the distributed storage means, it becomes impossible to read the data collected from one of the USB memory devices, and the stored data Security can be secured.

Further, the distributed storage unit causes each USB memory device to process in parallel the processing of storing the data input from the host device in each memory of the USB memory device and the other USB memory device. .
According to this, since data is written in parallel in a plurality of memories, the data writing speed is increased.

  In addition, it includes a distributed reading unit that reads out data stored in a distributed manner in each memory of the USB memory device and the other USB memory device by the distributed storage unit and outputs the data to the host device. .

Further, the data stored in the predetermined unit by the distributed storage unit of the USB memory device or the other USB memory device, and to be stored in the memory of the USB memory device, is temporarily stored for one or more units. A possible FIFO memory is provided.
According to this, since data to be written next can be received from the host device and stored in the FIFO memory even during writing to the memory, the data to be written next after the storage to the memory is completed. The writing time can be shortened as compared with the case of receiving.

In addition, the distribution is performed so that data is distributed and stored in each memory of each USB memory device from the USB memory device and the other USB memory devices connected in a daisy chain via the primary and secondary USB interfaces. A master selection unit that selects a master USB memory device that executes the storage unit; and when the USB selection is made by the master selection unit to be a master USB memory device, the distributed storage unit is When data is distributed and stored in each USB memory device and the master selection unit selects a USB memory device different from the USB memory device as the master USB memory device, the master USB memory device is distributed. The data distributed in the predetermined unit by the storage means is stored in the memory. Characterized in that it comprises a master-slave control means for controlling so as to store the re.
According to this, among the USB memory devices according to the present invention connected in a daisy chain in an arbitrary order, the USB memory device determined as the master USB memory device by the master determining unit controls the distributed storage. Therefore, it becomes possible to realize distributed storage by connecting the USB memory devices according to the present invention having the same configuration in a random order.

Further, when the USB memory device is selected to be the master USB memory device by the master selection means, a recognition signal indicating that the USB memory device is a slave device is transmitted to the host device. Slave signal control means for controlling not to transmit the recognition signal to the host device when a USB memory device different from the USB memory device is selected as the master USB memory device by the master selection means. It is characterized by providing.
Accordingly, only the master USB memory device can be recognized by the host device as a slave device connected to the USB interface of the host device. As a result, the host device only needs to perform the same processing as accessing one USB memory device, and there is no need to perform special processing for controlling a plurality of USB memory devices. In addition, the communication amount between the host device and a USB memory device other than the master USB memory device can be minimized.

In addition, the master selection unit selects, as the master USB memory device, a USB memory device that is most connected to the host device among the USB memory device and the other USB memory devices. .
According to this, the master USB memory device can control other USB memory devices by communication via only the secondary USB interface.

Furthermore, when the USB memory device is selected to be the master USB memory device by the master selection unit, the other USB memory device transmitted from the other USB memory device to the host device is Slave signal erasing means for erasing a recognition signal indicating that the device is a slave device is provided.
According to this, the host device recognizes only the master USB memory device as the slave device among the USB memory devices connected in a daisy chain via the USB interface.

Further, continuous storage means for storing data input from the host device in a continuous state in one of the memories of the USB memory device and the other USB memory device, and input from the host device And a storage system selection unit that selects whether the data is stored by the distributed storage unit or the continuous storage unit.
Further, the continuous storage means stores the data input from the host device in a continuous state in one of the memories of the USB memory device and the other USB memory device, and the remaining capacity of the memory When there is no more data, the continuation of the data is controlled to be stored in a continuous state in the memory of another USB memory device of the USB memory device and the other USB memory device. .
According to this, it is possible to selectively use the storage method by the distributed storage means and the storage method for storing data continuously.

Primary USB that can be connected to the USB interface of the host device or the USB interface of other slave devices connected in a daisy chain from the USB interface of the host device, and allows data to be input to and output from the host device. An interface, a plurality of memories capable of storing data, a writing means for storing data input from the host device via the primary USB interface in the memory, and reading the data stored in the memory; A USB memory device comprising: a reading unit configured to output to the host device via the primary USB interface, wherein the writing unit stores data input from the host device in the plurality of memories in predetermined units. Characterized by having distributed storage means for storing in a distributed manner To.
According to this, since the data is distributed and stored in a plurality of memories by the distributed storage means, it is impossible to read the data collected from one of the memories, and the security of the stored data can be ensured.

Further, the distributed storage means is characterized in that the processing for storing the data input from the host device in each memory is caused to process in parallel in each memory.
According to this, since data is written in parallel in a plurality of memories, the data writing speed is increased.

  In addition, the reading unit includes a distributed reading unit that reads the data distributed and stored in the plurality of memories by the distributed storage unit and outputs the data to the host device.

In addition, a FIFO memory capable of temporarily storing data received from the host device and to be stored in the memory is provided.
According to this, since data to be written next can be received from the host device and stored in the FIFO memory even during writing to the memory, the data to be written next after the storage to the memory is completed. The writing time can be shortened as compared with the case of receiving.

Further, the writing means has continuous storage means for continuously storing data input from the host device in the memory, and stores data input from the host device by the distributed storage means. Storage means selection means for selecting whether to store the data by the continuous storage means.
Further, the continuous storage means stores the data input from the host device in one of the plurality of memories in a continuous state, and when the remaining capacity of the memory is exhausted, the data Is stored in a continuous state in another memory of the plurality of memories.
According to this, it is possible to selectively use the storage method by the distributed storage means and the storage method for storing data continuously.

  The predetermined unit is a minimum writing unit of the memory.

  The memory is a flash memory.

In addition, a USB memory device control program according to the present invention has the following configuration in order to solve the above problems. That is, a plurality of slave devices can be connected to a host device having a USB interface that can be connected in a daisy chain, and the daisy chain is connected from the USB interface or the USB interface of another slave device connected in a daisy chain to the USB interface. A USB memory device control program for causing the host device to implement a writing unit for storing data in a memory of a plurality of USB memory devices connected to the memory, and a reading unit for reading data stored in the memory, The writing means includes distributed storage means for performing control for storing data in a predetermined unit in a distributed manner in the memories of the plurality of USB memory devices.
According to this, since the data is distributed and stored in the plurality of USB memory devices by the distributed storage means, it is impossible to read the data collected from one of the USB memory devices, and the security of the stored data is reduced. It can be secured.

Furthermore, the distributed storage means causes each USB memory device to process data stored in the memory of each USB memory device in parallel.
According to this, since data is written in parallel in a plurality of memories, the data writing speed is increased.

  Further, the reading means includes distributed reading means for reading data stored in a distributed manner in the memories of the plurality of USB memory devices by the distributed storage means.

Further, the writing means has continuous storage means for storing data in a continuous state in one of the plurality of USB memory devices, and the data is stored by the distributed storage means or the continuous storage means. A storage method selection means for selecting whether to store by the storage means is realized in the host device.
Further, the continuous storage means stores data in a continuous state in one of the plurality of USB memory devices, and when the remaining capacity of the memory is exhausted, the continuation of the data is It is characterized by being stored in a continuous state in a memory of another USB memory device among a plurality of USB memory devices.
According to this, it is possible to selectively use the storage method by the distributed storage means and the storage method for storing data continuously.

  The predetermined unit is a minimum writing unit of the memory.

  The memory is a flash memory.

  According to the USB memory device and the USB memory device control program for controlling the USB memory device according to the present invention, the capacity can be increased by connecting a plurality of devices, data access can be performed at high speed, and Security of saved data can be easily secured.

  The best mode for carrying out a USB memory device and a USB memory device control program according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an external view of a USB memory device A according to Embodiment 1 of the present invention.
The housing 2 of the USB memory device A is formed in a substantially rectangular parallelepiped shape.

  Insert one end of the USB memory device A into the USB terminal (female side) of a host device such as a computer or the USB terminal (female side) of another slave device connected in a daisy chain from the USB terminal of the host device. The primary USB terminal 4a (male side) that protrudes from the housing 2 is connectable. The USB memory device A functions as one of the slave devices for the host device by being connected to the USB terminal of the host device (or the USB terminal of another slave device connected in a daisy chain from the USB terminal of the host device). To do.

  The other end of the USB memory device A is provided with a concave secondary USB terminal 6a (female side) that can be connected by inserting a primary USB terminal of another slave device. By inserting the primary USB terminal 4a of another USB memory device A having the same configuration into the secondary USB terminal 6a, a plurality of USB memory devices A can be connected in a daisy chain.

FIG. 2 is an explanatory diagram illustrating an example of connection between the host computer H as a host device and the USB memory device A according to the first embodiment.
As shown in the upper stage a, the USB terminal 4a of the USB memory device A is connected to the USB terminal (not shown) of the host computer H, and the USB terminal Ma of the mouse M as the slave device is inserted into the USB terminal 6a. The host computer H is communicably connected to each of the USB memory device A and the mouse M.

  2, the USB terminal 4a of the USB memory device A1 is connected to a USB terminal (not shown) of the host computer H, and a plurality of USB memory devices A1, A2, A3 are connected to the primary. Also, it can be connected in a daisy chain via the secondary USB terminals 4a and 6a.

  Although not shown, another slave device may be connected between the USB memory device A in the upper stage a or the USB memory apparatus A1 in the lower stage b and the host computer H, or a plurality of USB memory devices A1 in the lower stage b. , A2 and A3, another slave device may be connected.

  Next, the internal configuration of the USB memory device A will be described with reference to the block diagram of FIG.

  The USB memory device A includes a control unit (not shown) having a CPU, a memory, and other electronic circuits. The control unit executes each of the means described later (primary and secondary USB interfaces 4 and 6, storage method selection switches 8 and 9, USB controller, etc.) by executing the circuit configuration and the firmware program stored in the ROM or the like. 10, 12, 14, slave signal control means 30, master-slave control switches 16, 17, master selection means 18, distributed storage / readout means 20, continuous storage / readout means 22, USB signal branching means 24, memory controller 26, and FIFO Memory 28) is realized.

The primary USB interface 4 includes the USB terminal 4a and a USB communication circuit, and can input / output data to / from a host device connected to the USB terminal 4a directly or via another slave device.
A USB signal input from the primary USB interface 4 (a USB signal transmitted from the host device to one or more slave devices connected in a daisy chain) is in the state of the storage system selection switches 8 and 9 (described later). In response, the signal is input to the USB signal branching unit 24 directly or via the distributed storage / reading unit 20 or the continuous storage / reading unit 22.

The storage system selection switches 8 and 9 as storage system selection means are switches that allow the user to select how data is stored in the flash memory 7 (operation mode).
The two storage system selection switches 8 and 9 are configured to always operate in conjunction with each other. That is, when the storage system selection switch 8 is selected to flow an input signal from the primary USB interface 4 to the terminal 8a, the storage system selection switch 9 is linked to the terminal 9a corresponding to the terminal 8a. Configured to connect. Similarly, when the storage system selection switch 8 is connected to the terminal 8b, the storage system selection switch 9 is connected in conjunction with the terminal 9b corresponding to the terminal 8b, and the storage system selection switch 8 is connected to the terminal 8c. In this case, the storage system selection switch 9 is configured to be connected to the terminal 9c corresponding to the terminal 8c.
Thereby, as described above, the USB signal input from the primary USB interface 4 is directly or depending on the state of the storage mode selection switches 8 and 9, or the distributed storage / reading means 20 or the continuous storage / reading means 22 or the like. To the USB signal branching means 24.

  The storage system selection switches 8 and 9 may be provided as, for example, dip switches that are exposed on the outer surface of the housing 2 and can be operated by the user, or according to predetermined commands received from the host device via the primary USB interface 4. It may be provided as switching means realized by software (not necessarily limited to a switch having physical terminals 8a, 8b, 8c, 9a, 9b, 9c).

The USB signal branching unit 24 branches the USB signal input from the primary USB interface 4 and outputs it to the secondary USB interface 6 and the USB controller 14.
As a result, the USB signal from the host device can flow to other slave devices connected to the secondary USB interface 6.
Also, USB signals from other slave devices connected to the secondary USB interface 6 are output from the primary USB interface 4 via the USB signal branching means 24.
That is, the USB signal branching unit 24 serves as a hub for branching the USB signal, and connects a plurality of slave devices connected in a daisy chain via the primary USB interface 4 and the secondary USB interface 6 to a tree structure.

  On the other hand, the USB controller 14 includes the USB signal included in the USB signal input from the USB signal branching unit 24 (the USB signal transmitted from the host device to one or more slave devices connected in a daisy chain). Data transmitted to the memory device A is extracted and written into the FIFO memory 28. The memory controller 26 reads the data written in the FIFO memory 28 at any time, writes the data to the flash memory 7 if it is data to be written to the flash memory 7, and the corresponding data from the flash memory 7 if it is a read command. Are transmitted from the primary USB interface 4 to the host device via the USB controller 14 and the USB signal branching means 24.

In the USB memory device A, the operation mode for reading / writing data from / to the flash memory 7 is switched according to the selection state of the storage method selection switches 8, 9.
As selectable operation modes, there are three operation modes, a normal operation mode, a distributed storage mode, and a continuous storage mode, which will be described later.

When selecting the normal operation mode, the user sets the storage system selection switches 8 and 9 to be connected to the terminals 8a and 9a, respectively. The setting can be performed, for example, by switching a DIP switch or transmitting a predetermined command from the host device.
Similarly, when the continuous storage mode is selected, the storage mode selection switches 8 and 9 are set to be connected to the terminals 8b and 9b, and when the distributed storage mode is selected, the storage mode selection switches 8 and 9 are set. It is set to connect to the terminals 8c and 9c.

(Normal operation mode)
The normal operation mode is an operation mode in which data input from the host device is continuously stored in the flash memory 7 as it is.

  When the normal operation mode (terminals 8 a and 9 a) is selected by the storage system selection switches 8 and 9, the USB signal input from the primary USB interface 4 is input to the USB signal branching unit 24 as it is. The USB signal is branched by the USB signal branching means 24, transmitted to another device via the secondary USB interface 6, and input to the USB controller 14. In addition, USB signals from other slave devices connected to the secondary USB interface 6 are directly output from the primary USB interface 4 via the USB signal branching unit 24.

  The USB controller 14 is connected to the host device when the host device connected via the primary USB interface 4 is activated, or when connected directly to the host device via the primary USB interface 4 or via another storage device. When communication with the device becomes possible, the device communicates with the host device and transmits a recognition signal indicating that the USB memory device A is a USB device as a slave device connected to the host device. Based on this recognition signal, the control unit of the host device recognizes that the USB memory device A is connected to the USB interface of the host device, and can communicate data with the USB memory device A.

When the host device reads / writes data to / from the USB memory device A, the host device sends a USB signal including an instruction to read / write data to / from the flash memory to the USB memory device A via the USB interface. To do. The USB signal is input to the USB memory device A via the primary USB interface 4.
The host device is connected not only to the USB memory device A but also to other storage devices connected in a daisy chain from the USB interface of the host device (for example, the mouse M in the upper row a in FIG. 2 and other USB memory devices in the lower row b). In contrast, a USB signal for controlling them is output from the same USB interface.

  When the normal operation mode (terminals 8 a and 9 a) is selected by the storage system selection switches 8 and 9, the USB signal is input to the USB controller 14 via the USB signal branching unit 24. As described above, the USB controller 14 extracts data and instructions transmitted to the USB memory device A from USB signals transmitted to one or more slave devices included in the USB signal. Then, the memory controller 26 reads / writes the flash memory 7 based on the data and instructions.

(Distributed storage mode)
In the distributed storage mode, data input from the host device is stored in the flash memories 7 of the USB memory device A and other USB memory devices A connected in a daisy chain via the primary and secondary USB interfaces 4 and 6. This is an operation mode in which predetermined units are distributed and stored.

When the distributed storage mode (terminals 8 c, 9 c) is selected by the storage method selection switches 8, 9, the USB signal input from the primary USB interface 4 is sent via the USB controller 10 to the master selection means 18 and Input to the distributed storage / readout means 20. The USB signal is changed by the master selection unit 18 and the distributed storage / reading unit 20, and then sent to the USB controller 14 and the secondary USB interface 6 via the USB controller 12 and the USB signal branching unit 24. Is output.
Also, USB signals from other slave devices connected to the secondary USB interface 6 are input to the master selection means 18 and the distributed storage / readout means 20 via the USB signal branching means 24 and the USB controller 12.

  The master selection means 18 is connected to a plurality of USB memory devices A1, A2,... Connected in a daisy chain as shown in the lower part b of FIG. This is means for selecting a master USB memory device that executes the reading means 20 and performs control to distribute and store data in each flash memory 7 of each USB memory device A1, A2,.

  When the host device connected via the primary USB interface 4 is activated, or when the master selection unit 18 is connected directly to the host device via the primary USB interface 4 or via another storage device, etc. When communication with the host device becomes possible, the USB memory devices A1, A2,... Connected to each other via the primary and secondary USB interfaces 4 and 6 communicate with each other, thereby connecting the beads. Among the plurality of USB memory devices A1, A2,... Connected to the USB device (the USB memory device A1 in FIG. 2) connected to the host device side (side closer to the host device). The USB memory device A1 is determined as the master USB device. As a result, the master selection unit 18 of each of the USB memory devices A1, A2,... Recognizes whether or not the own USB memory device has become a master USB memory device.

  Note that the master selection unit 18 is not necessarily limited to the configuration in which the USB memory device most connected to the host device is selected as the master USB memory device, and the master USB memory device may be selected according to other criteria. Good. For example, the master selection unit 18 may be provided on a switch that can be operated by the user, and the user may select the master USB device.

The master selection unit 18 of the USB memory device A1 selected as the master USB memory device sets the master / slave control switches 16 and 17 so that the USB signal input / output to / from the primary USB interface 4 passes through the distributed storage / readout unit 20. Control is performed so as to connect to terminals 16a and 17a, respectively.
On the other hand, the master selection unit 18 of the USB memory devices A2 and A3 not selected as the master USB memory device controls the master and slave so that the USB signal input to and output from the primary USB interface 4 does not pass through the distributed storage / readout unit 20. Control is performed so that the switches 16 and 17 are connected to the terminals 16b and 17b, respectively.

The two master-slave control switches 16 and 17 are configured to always operate in conjunction with each other. That is, when the master-slave control switch 16 is connected to the terminal 16a, the master-slave control switch 17 is configured to be connected to the terminal 17a corresponding to the terminal 16a in conjunction with it. Similarly, when the master-slave control switch 16 is connected to the terminal 16b, the master-slave control switch 17 is configured to connect in conjunction with the terminal 17b corresponding to the terminal 16b.
The master-slave control switches 16 and 17 may be provided as switching means realized by software (firmware program) (not necessarily limited to switches having physical terminals 16a, 16b, 17a, and 17b). ).

In addition, the USB controller 14 transmits the recognition signal to the host device when communication with the host device becomes possible, as in the operation in the normal operation mode described above. Here, in the distributed storage mode, this recognition signal is input to the master selection means 18.
When the USB memory device is selected as the master USB memory device by the master selection unit 18, the slave signal control unit 30 transmits this recognition signal to the host device via the primary USB interface 4. On the other hand, when a USB memory device other than the USB memory device is selected as the master USB memory device (that is, when the USB memory device is not selected as the master USB memory device), the slave signal The control unit 30 performs control so that the recognition signal is not transmitted to the host device.

  If the master selection means 18 receives this control signal before determining the master USB memory device, the slave signal control means 30 temporarily holds the recognition signal and the master selection means 18 When the master USB memory device is selected by the above, it is determined whether or not to transmit the recognition signal to the host device based on the selection result.

According to the operation of the slave signal control means 30, only the USB memory device A1 connected most to the host device side transmits a recognition signal to the host device, and the USB memory device A2 connected downstream from the USB memory device A1. , A3 does not transmit a recognition signal to the host device.
Therefore, the host device recognizes only the master USB memory device A1 as a slave device by the only recognition signal transmitted from the master USB memory device A1, and does not recognize the other USB memory devices A2 and A3.

  Instead of the slave signal control means 30, slave signal erasure means that can erase the recognition signal input from the secondary USB interface 6 from another USB memory device is provided, and a USB memory other than the master USB memory device A1 is provided. The recognition signals transmitted from the devices A2 and A3 may be erased by the slave signal erasing means of the master USB memory device A1, so that the recognition signals of the USB memory devices A2 and A3 are not received by the host device. .

When the USB memory device A1 transmits a recognition signal to the host device, the host device recognizes the total data capacity that can be stored in the flash memories 7, 7,... Of the USB memory devices A1, A2,. The capacity of the USB memory device A1 is preferably transmitted to the host device. For example, if the sizes of the flash memories 7 of the three USB memory devices A1, A2, and A3 are all 1 Gbyte, the information on the total data capacity to be transmitted to the host device is 3 Gbyte.
According to the writing method in the distributed writing mode described later, since the amount of data written to each flash memory 7 of each USB memory device A1, A2,... Is equal, each flash memory 7 of USB memory device A1, A2,. When the data capacity varies, the total memory capacity is a capacity obtained by a calculation formula of “the smallest flash memory capacity among a plurality of connected USB memory devices × the number of USB memory devices”. .

When the host device reads / writes data to / from the USB memory device, the USB including a command for instructing the master USB memory device A1 to read / write to the flash memory via the USB interface of the host device. Send a signal. The USB signal is input to the USB memory device A1 via the primary USB interface 4.
In the distributed storage mode, the USB signal input to the USB memory device A1 is input to the distributed storage / readout unit 20 via the terminal 16a of the master / slave control switch 16.

When the data (USB signal) to be written to the flash memory is input, the distributed storage / reading means 20 of the USB memory device A1 is connected to the USB memory device A1 and the downstream at a predetermined unit. Control is performed to be distributed and stored in the respective flash memories 7 of the USB memory devices A2 and A3.
Specifically, a new USB signal in which the destination of the write data transmitted from the host device to the USB memory device A1 is rewritten in order to each of the USB memory devices A1, A2, and A3 for each predetermined unit. And the USB signal is transmitted to the USB memory devices A1, A2, A3 via the USB signal branching means 24.

  Specifically, the predetermined unit is preferably the minimum writing unit (generally called a page) of the flash memory 7 (generally, the size of one page of the flash memory is about 256 bytes to 512 bytes). Often). Write data from the host device is generally transmitted in units of pages, which is the minimum write unit of the flash memory 7. Therefore, by configuring the unit of data distributed by the distributed storage / write unit 20 as a page unit, the distributed storage / read unit 20 can transmit the destination of data input from the host device to the USB memory device A1. Can be realized by a simple process of rewriting A1 → A2 → A3 → A1 → A2.

FIG. 4A is an explanatory diagram showing a recording method using the USB memory devices A1, A2, and A3 according to the first embodiment.
First, when the first page of data to be stored is transferred from the host device to the USB memory device A1 together with a write command to be written to the USB memory device A1, the distributed memory / memory of the USB memory device A1 as the master USB memory device is transferred. The reading unit 20 outputs the data as it is to the USB signal branching unit 24. Then, the data is written into the FIFO memory 28 via the USB controller 14 of the USB memory device A1, and is sequentially written from the FIFO memory 28 into the flash memory 7 via the memory controller 26.

  Here, since the USB communication speed is faster than the writing speed of the flash memory 7, the writing of data from the FIFO memory 28 to the flash memory 7 is performed for a while after all the data of the first page is written to the FIFO memory 28. This is continued (refer to “first page” in FIG. 4A).

When the writing of the first page of data to the FIFO memory 28 is completed, the second page of data can be transferred, and the host device transfers the second page of data to the USB memory device A1.
At this time, the distributed storage / reading means 20 of the USB memory device A1 rewrites the transmission destination of the data write command for the second page to the address of the USB memory device A2, and outputs it to the USB signal branching means 24. The write command is not extracted to the USB controller 14 of the USB memory device A1 because the transmission destination is rewritten to the address of the USB memory device A2.

The write command and data whose transmission destination is rewritten to the address of the USB memory device A2 are input to the USB memory device A2 connected via the secondary USB interface 6 of the USB memory device A1.
In the USB memory device A2 which is not the master USB memory device, the master-slave control switches 16 and 17 are set not to go through the distributed storage / reading means 20, so that the command and data are directly input to the USB signal branching means 24. The data is written to the flash memory 7 of the USB memory device A2 via the USB controller 14, the FIFO memory 28, and the memory controller 26 of the USB memory device A2 (“second page” in FIG. 4A).
Similarly, the write instruction and data for the third page are written to the flash memory 7 of the USB memory device A3 with the write destination being rewritten to the USB memory device A3.

The write destinations of the data on and after the fourth page are also changed in order of A1 → A2 → A3... By the distributed storage / readout means 20 of the USB memory device A1, which is the master USB memory device.
At this time, the transferred data on and after the fourth page is written into the FIFO memory 28 of each USB memory device to which the data is written. At this time, in the USB memory device, if writing of the previously transferred page to the flash memory 7 is not completed, writing of the next written page to the flash memory 7 is started after the writing is completed. (See FIG. 4 (a), page 4 onwards).

  As described above, according to the USB memory devices A1, A2,... According to the first embodiment, the processing for storing data in the flash memories 7 of the plurality of USB memory devices A1, A2,. .

  As a comparative example, FIG. 4B shows a storage method of a conventional USB memory device in which data is continuously stored in the flash memory 7. In the conventional USB memory device, even if data can be stored in advance by storing a plurality of pages of data in the FIFO memory, the next page cannot be written until the first page is written. Compared to this storage method, it takes much time to write data.

  In the distributed storage mode, when the master USB memory device A1 receives an instruction to read data from the host device, the distributed storage / reading unit 20 performs the operation of each of the USB memory devices A1, A2 as shown in FIG. , A3 sequentially transmits a read command for each page to sequentially read data from each of the USB memory devices A1, A2, A3, and transmits the read data to the host device (distributed read means).

In order to increase the speed of the distributed reading means, the data read command and the data transfer command are separated, and as shown in FIG. In addition, a read command for each page is transmitted and a data transfer command for the first page is transmitted. The memory controller 26 of each USB memory device A1, A2, A3 stores the read data in the FIFO memory 28 in response to the data read command at the time of distributed reading. When the data transfer command is received from the master USB memory device A1, the data read into the FIFO memory 28 is transmitted to the host device. When the data transfer corresponding to the data transfer command is completed, the host device issues a next page data transfer command to transfer the next page of data.
According to this configuration, the process of reading data from each flash memory 7 of the plurality of USB memory devices A1, A2,... According to the same principle as the speeding up method of the distributed writing means shown in FIG. A plurality of USB memory devices A1, A2,.

(Continuous storage mode)
The continuous storage mode is one of the flash memory 7 of the USB memory device and other USB memory devices in which data input from the host device is connected in a daisy chain via the primary and secondary USB interfaces 4 and 6. When the remaining capacity of the flash memory 7 is exhausted, the continuation of the data is stored in the flash memory 7 of another USB memory device in a continuous state. .

When the continuous storage mode (terminals 8b and 9b) is selected by the storage system selection switches 8 and 9, the USB signal input from the primary USB interface 4 is continuously stored and read out via the USB controller 10. 22 is input. The USB signal is changed by the continuous storage / reading means 22 and then output to the USB controller 14 and the secondary USB interface 6 via the USB controller 12 and the USB signal branching means 24.
In addition, USB signals from other slave devices connected to the secondary USB interface 6 are input to the continuous storage / readout means 22 via the USB signal branching means 24 and the USB controller 12.

  Although not shown, even in the continuous storage mode, the master USB memory device is determined by executing the same functions as the master selection unit 18, slave signal control unit 30, and master-slave control switches 16 and 17 in the distributed storage mode. Thus, the recognition signal to the host device is controlled, and only the master USB memory device is configured to execute the continuous storage / reading means 22.

When the data (USB signal) to be written to the flash memory is input from the host device, the continuous storage / reading means 22 of the USB memory device A1 (lower b in FIG. 2) that is the master USB memory device starts with the USB memory. The data is stored in a continuous state in the flash memory 7 of the device A1.
Thereafter, when there is no remaining capacity in the flash memory 7, the subsequent transmission destination of the data is rewritten to the address of the USB memory device A2 connected downstream, so that the flash memory 7 of the USB memory device A2 is rewritten. The continuation of the data is stored in a continuous state.
Further, when the remaining capacity of the flash memory 7 of the USB memory device A2 runs out, the continuous storage / reading means 22 of the USB memory device A1 uses the USB memory device connected downstream of the destination of the data. By rewriting the address A3, the continuation of the data is stored in a continuous state in the flash memory 7 of the USB memory device A3.

  In the continuous storage mode, when the USB memory device A1 receives an instruction to read data from the host device, the distributed storage / reading means 20 reads the data to be read from each of the USB memory devices A1, A2, A3, Send to the host device.

  In the first embodiment, all of the USB memory devices A1, A2,... Connected in a daisy chain are assumed to have the same configuration. However, the distributed storage / reading means 20 and the continuous storage / reading means 22 are different from each other. Provided in one USB memory device, the other USB memory devices do not have the distributed storage / readout means 20 and the continuous storage / readout means 22, but the distributed storage / readout means 20 or the continuous storage / readout means of the one USB memory device. 22 may be configured to perform control to store data in a distributed or continuous manner in another USB memory device.

  The appearance of the USB memory device B according to the second embodiment of the present invention and the connection example with the host device are the same as those of the USB memory device A according to the first embodiment shown in FIG. 1 and FIG. To do.

  FIG. 6 is a block diagram showing an internal configuration of the USB memory device B according to the second embodiment of the present invention. In FIG. 6, the same components as those of the USB memory device A according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The USB memory device B includes a control unit (not shown) having a CPU, a memory, and other electronic circuits. The control unit executes each of the means described later (primary and secondary USB interfaces 4 and 6, USB controller 14, FIFO memory 28, storage system, etc.) by executing the circuit configuration and the firmware program stored in the ROM or the like. A selection switch 32, distributed storage / reading means 34, continuous storage / reading means 36, memory controller 26, and USB signal branching means 24) are realized.

  The USB memory device B includes a plurality (three) of flash memories 7a, 7b, and 7c, and memory controllers 26, 26, and 26 corresponding to the flash memories 7a, 7b, and 7c, respectively.

  A USB signal input from the primary USB interface 4 (a USB signal transmitted from the host device to one or more slave devices connected in a daisy chain) is directly input to the USB signal branching unit 24.

  The storage system selection switch 32 as a storage system selection unit is a switch that allows the user to select how data is stored in the flash memories 7a, 7b, and 7c (operation mode). As selectable operation modes, there are two operation modes, a distributed storage mode and a continuous storage mode.

  The storage method selection switch 32 may be provided as, for example, a dip switch that is exposed on the outer surface of the housing 2 and can be operated by the user, or software according to a predetermined command received from the host device via the primary USB interface 4. It may be provided as switching means realized by (not necessarily limited to a switch having physical terminals 32a and 32b).

When the distributed operation mode is selected, the user sets the storage method selection switch 32 to be connected to the terminal 32a. The setting can be performed, for example, by switching a DIP switch or transmitting a predetermined command from the host device.
Similarly, when the continuous storage mode is selected, the storage system selection switch 32 is set to be connected to the terminal 32b.
Thus, depending on the state of the storage system selection switch 32, the flash memory 7a, 7b, 7c is selected to read / write data by the distributed storage / reading means 34 or to read / write data by the continuous storage / reading means 36. Is done. That is, when the storage system selection switch 32 is connected to the terminal 32a, the flash memory 7a, 7b is distributed by the distributed storage / reading means 34, and when it is connected to the terminal 32b, the continuous storage / reading means 36 is used. , 7c, data is read and written.

(Distributed storage mode)
The distributed storage mode is an operation mode in which data input from the host device is distributed and stored in a plurality of flash memories 7a, 7b, 7c for each predetermined unit.

  When the storage mode selection switch 32 selects the distributed storage mode (terminal 32a), the USB signal input from the primary USB interface 4 and passed through the USB signal branching unit 24 and the USB controller 14 is distributed storage / reading unit. 34.

When the data (USB signal) to be written to the flash memory is input, the distributed storage / reading unit 34 stores the data in units of a predetermined unit in each flash memory 7a, 7b, 7c, 7a → 7b → 7c → 7a → 7b... Is controlled so as to be distributed and stored in order.
Specifically, the predetermined unit is desirably a minimum writing unit (page) of the flash memories 7a, 7b, and 7c.

  According to the recording method using the USB memory device B according to the second embodiment, the processing for storing data in the plurality of flash memories 7a, 7b, and 7c is performed in parallel as in the recording method shown in FIG. Can be made.

In the distributed storage mode, when the USB memory device B receives an instruction to read data from the host device, the distributed storage / read means 34 sequentially reads the data from each of the flash memories 7a, 7b, 7c, and reads the read data. Is transmitted to the host device (distributed readout means).
At this time, the distributed storage / reading means 34 controls each of the memory controllers 26, 26, 26, and, based on the same principle as the distributed reading means shown in FIG. 5B, a plurality of flash memories 7a, 7b, 7c. In parallel, the process of reading data from the flash memory 7a, 7b, 7c is stored in the FIFO memory 28, and the data of each page stored in the FIFO memory 28 is stored. If data is transferred to the host device in order, data reading can be speeded up.

(Continuous storage mode)
In the continuous storage mode, data input from the host device is stored continuously in one of the plurality of flash memories 7a, 7b, 7c, and when the remaining capacity of the flash memory runs out, This is an operation mode in which the continuation of the data is stored in a continuous state in another flash memory of the flash memories 7a, 7b, and 7c.

When the data (USB signal) to be written to the flash memory is input from the host device, the continuous storage / reading means 36 first stores the data in the flash memory 7a in a continuous state.
Thereafter, when the remaining capacity of the flash memory 7a runs out, the continuation of the data is stored in the flash memory 7b in a continuous state.
When the remaining capacity of the flash memory 7b runs out, the continuous storage / reading means 36 causes the flash memory 7c to store the continuation of the data in a continuous state.

  In the continuous storage mode, when the USB memory device A1 receives a command to read data from the host device, the continuous storage / reading means 36 reads the data to be read from each flash memory 7a, 7b, 7c, and Send to device.

Next, the best mode for carrying out a USB memory device control program according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 7 is an explanatory diagram showing a configuration of the USB memory device driver P as a USB memory device control program according to the third embodiment of the present invention and an example of its use.

A host computer H as a host device includes a control unit (not shown) having a CPU, a memory, other electronic circuits, and the like and capable of executing a program, and a USB interface 38 capable of connecting a plurality of slave devices in a daisy chain. Prepare. In addition, the host computer H includes input means (not shown) such as a mouse and a keyboard that allow a user to input information and operations, and display means (not shown) such as a display that can display information to the user. Prepare.
A plurality of USB memory devices C1, C2,... Can be connected to the USB interface 38 of the host computer H as shown in FIG.
In FIG. 7, the internal configurations of the USB memory devices C2 and C3 are omitted, but they have the same internal configuration as the USB memory device C1.
Although not shown, another slave device may be connected between the USB memory devices C1, C2,... Or at the end thereof.

In the host computer H, a file system 40, a USB memory device driver P, and the like are provided (installed) so as to be readable by the computer.
By executing the USB memory device driver P, the control unit of the host computer H causes each unit to be described later (storage method selection switches 46 and 47, distributed storage / reading unit 42, and continuous storage / reading unit 44). Realize.

The USB memory devices C1, C2,... Include a primary USB interface 4, a secondary USB interface 6, a flash memory 7, a USB signal branching unit 24, a USB controller 14, a FIFO memory 28, a memory controller 26, And a flash memory 7. In addition, about the structure similar to the said Example 1 and 2, the same code | symbol is attached | subjected and description is abbreviate | omitted.
In the third embodiment, control (distributed storage means) for distributing and storing data in the flash memories 7 of the USB memory devices C1, C2,... Is performed on the host computer H side. C2... Does not need to be provided with distributed storage means.

  The storage system selection switches 46 and 47 as storage system selection means are switches that allow the user to select how the USB memory devices C1, C2,... Store data (operation mode). As selectable operation modes, there are two operation modes, a distributed storage mode and a continuous storage mode.

The storage method selection switches 46 and 47 are set by, for example, a user performing a predetermined operation on the predetermined setting screen displayed on the display unit by the execution of the USB memory device driver P by the input unit. (The storage system selection switches 46 and 47 are not necessarily limited to switches having physical terminals 46a, 46b, 47a and 47b).
When the user selects the distributed operation mode, the storage system selection switches 46 and 47 are connected to the terminals 46a and 47a, respectively, and set to read / write data to / from the USB memory device by the distributed storage / read means 42. On the other hand, when the user selects the continuous operation mode, the storage system selection switches 46 and 47 are connected to the terminals 46b and 47b, respectively, and are set to read / write data by the continuous storage / read means 44.

A user operation on the input means of the host computer H or an application program (not shown) provided on the host computer H so as to be readable is executed by the control unit, and the file system 40 reads / writes data from / to the USB memory device. When instructed, the file system 40 reads and writes data via the USB memory device driver P.
The USB memory device driver P accesses the file system 40 on the assumption that only one USB memory device is connected to the USB interface 38.

(Distributed storage mode)
The distributed storage mode is an operation mode in which data input from the file system 40 is distributed and stored in predetermined units in the flash memories 7, 7,... Of the plurality of USB memory devices C1, C2,.

When the distributed storage mode (terminals 46 a, 47 a) is selected by the storage method selection switches 46, 47, a data read / write command (access command) input from the file system 40 is sent to the distributed storage / reader 42. Entered. Then, the access command is changed by the distributed storage / reading means 42 and then output to the USB memory devices C1, C2,... Via the USB interface 38 as USB signals.
Further, USB signals from the respective USB memory devices C1, C2,... Are input to the distributed storage / reading means 42 via the USB interface 38, and output to the file system 40 via the distributed storage / reading means 42.

  When the data to be written to the USB memory device is input from the file system 40 from the file system 40, the distributed storage / read-out means 42 sets the transmission destination of the write data for each of C1, C2, and C3 in order for each predetermined unit. Control is performed to set the USB memory device to generate a USB signal and transmit the USB signal to the USB memory devices C1, C2, and C3 via the USB interface 38.

  Specifically, the predetermined unit is desirably a minimum writing unit (page) of the flash memory 7. Write data from the file system 40 is generally transmitted in units of pages, which is the minimum write unit of the flash memory 7 of the USB memory devices C1, C2,. Therefore, by configuring the unit of data distributed by the distributed storage / write unit 42 as a page unit, the distributed storage / read unit 42 determines the transmission destination of the write data input from the file system 40 in order. In addition, distributed writing can be realized by a simple process of setting C1, C2, C3, C1, C2,.

  According to the recording method using the USB memory device driver P according to the third embodiment, data is stored in each flash memory 7 of the plurality of USB memory devices C1, C2, and C3, as in the recording method shown in FIG. Can be processed in parallel.

  In the distributed storage mode, when the USB memory device driver P receives an instruction to read data from the file system 40, the distributed storage / read means 42 reads each page from the USB memory devices C1, C2, and C3. By sequentially transmitting the command, the data is sequentially read from each of the USB memory devices C1, C2, and C3, and the read data is sent to the file system 40 (distributed read means).

(Continuous storage mode)
In the continuous storage mode, the write data input to the file system 40 is stored in a continuous state in one of the flash memories 7, 7,... Of the plurality of USB memory devices C1, C2,. In this operation mode, when the remaining capacity of 7 disappears, the continuation of the data is stored continuously in the flash memory 7 of another USB memory device C1, C2,.

When the data to be written to the USB memory device is input from the file system 40, the continuous storage / reading means 44 first stores the data in the flash memory 7 of the USB memory device C1 in a continuous state.
Thereafter, when the remaining capacity of the flash memory 7 runs out, the continuation of the data is stored in a continuous state in the flash memory 7 of the USB memory device C2.
When the remaining capacity of the flash memory 7 is exhausted, the continuous storage / reading means 36 stores the continuation of the data in the flash memory 7 of the USB memory device C3 in a continuous state.

  In the continuous storage mode, when the continuous storage / reading means 44 receives an instruction to read data from the file system 40, the continuous storage / reading means 44 sends the data to be read out to the USB memory devices C1, C2, C3. Read from the flash memory 7 and pass to the file system 40.

  According to the USB memory devices A and B and the USB memory device control driver P according to the first to third embodiments, the capacity can be increased by connecting a plurality of USB memory devices, and data can be transferred in the distributed write mode. Since data is written and read in parallel in a plurality of memories, the data writing and reading speed is increased, and the data is distributed and stored in the memories of the plurality of USB memory devices by the distributed storage means. It becomes impossible to read data collected from one, and the security of stored data can be ensured.

In the above embodiment, the host computer is used as the host device. However, the host device is not limited to what is used as a so-called computer, and any device having a USB interface and having a function of reading and writing data from and to a USB memory device. Including equipment.
Further, the writing unit (predetermined unit) at the time of distributed writing is not limited to the page unit of the flash memory, and the memory used for the USB memory device is not limited to the flash memory.

It is a figure (plan view) showing an appearance of a USB memory device according to the present invention. It is explanatory drawing which shows the aspect at the time of connecting the USB memory device based on this invention to a host apparatus. 1 is a block diagram showing an internal configuration of a USB memory device according to the present invention. It is explanatory drawing which shows the recording system using a USB memory device, (a) shows the recording system using the USB memory device based on this invention, (b) shows the recording system using the conventional USB memory device. It is explanatory drawing which shows the distributed reading system using the USB memory device based on this invention, (a) shows the reading system by the 1st distributed reading means, (b) shows the reading system by the 2nd distributed reading means 2. . 1 is a block diagram showing an internal configuration of a USB memory device according to the present invention. It is explanatory drawing which shows the structure of the USB memory device control program based on this invention, and its usage example.

Explanation of symbols

A, A1, A2, A3, B USB memory device H Host computer (host device)
M mouse (other slave devices)
P USB memory device driver (USB memory device control program)
2 Housing 4 Primary USB interface 6 Secondary USB interface 7, 7a, 7b, 7c Flash memory (memory)
8, 9, 32, 46 Storage system selection switch (storage system selection means)
16, 17 Master-slave control switch (master-slave control means)
18 Master selection means 20, 34, 42 Distributed storage / reading means (distributed storage means / distributed reading means)
22 Continuous storage / readout means (continuous storage means)
24 signal branching means 28 FIFO memory 30 slave signal control means 36, 44 continuous storage / reading means (continuous storage means)
38 USB interface of host device 40 File system

Claims (25)

A primary USB interface that can be connected to the USB interface of the host device or the USB interface of another slave device connected in a daisy chain from the USB interface of the host device, and that can input and output data with the host device; ,
A secondary USB interface provided so as to be connectable to a USB interface of another slave device and enabling data input / output to / from the other slave device;
A memory capable of storing data;
Writing means for storing, in the memory, data input from the host device via the primary USB interface;
A USB memory device comprising: reading means for reading data stored in the memory and outputting the data to the host device via the primary USB interface;
Control for storing data input from the host device in a predetermined unit dispersedly in each memory of the USB memory device and other USB memory devices connected in a daisy chain via the primary and secondary USB interfaces. A USB memory device comprising distributed storage means for performing.   The distributed storage unit causes each USB memory device to perform parallel processing of storing data input from the host device in each memory of the USB memory device and the other USB memory device. The USB memory device according to 1.   The distributed storage unit includes a distributed reading unit that reads out data stored in a distributed manner in each memory of the USB memory device and the other USB memory device and outputs the data to the host device. The USB memory device according to 1 or 2.   The data stored in the predetermined unit by the distributed storage unit of the USB memory device or the other USB memory device, and the data to be stored in the memory of the USB memory device can be temporarily stored for one or more units. The USB memory device according to claim 1, further comprising a FIFO memory. The distributed storage means for distributing and storing data in each memory of each USB memory device from the USB memory device and the other USB memory devices connected in a daisy chain via the primary and secondary USB interfaces Master selection means for selecting a master USB memory device to execute
When the master selection unit selects the USB memory device as a master USB memory device, the distributed storage unit is executed to distribute and store data in the USB memory devices, and the master selection unit When a USB memory device different from the USB memory device is selected to be the master USB memory device, the data distributed in the predetermined unit by the distributed storage unit of the master USB memory device is stored in the memory. 5. The USB memory device according to claim 1, further comprising: a master-slave control unit configured to perform control.   When the master selection unit selects the USB memory device to be the master USB memory device, it sends a recognition signal indicating that the USB memory device is a slave device to the host device, and Slave signal control means for controlling not to transmit the recognition signal to the host device when the selection means selects a USB memory device different from the USB memory device as the master USB memory device. The USB memory device according to claim 5.   The master selection unit selects, as the master USB memory device, a USB memory device that is most connected to the host device among the USB memory device and the other USB memory devices. The USB memory device according to 5 or 6.   When the master selection unit selects the USB memory device to be the master USB memory device, the other USB memory device transmits to the host device, and the other USB memory device is a slave device. The USB memory device according to claim 7, further comprising slave signal erasing means for erasing a recognition signal indicating that the data is recognized. Continuous storage means for storing data input from the host device in one of the memories of the USB memory device and the other USB memory device in a continuous state;
9. A storage method selection unit that selects whether the data input from the host device is stored by the distributed storage unit or the continuous storage unit. The USB memory device according to claim 1.   The continuous storage means stores data input from the host device in one of the memories of the USB memory device and the other USB memory device in a continuous state, and the remaining capacity of the memory is eliminated. In this case, control is performed to store the continuation of the data in a continuous state in a memory of another USB memory device of the USB memory device and the other USB memory device. 9. The USB memory device according to 9. A primary USB interface that can be connected to the USB interface of the host device or the USB interface of another slave device connected in a daisy chain from the USB interface of the host device, and that can input and output data with the host device; ,
A plurality of memories capable of storing data;
Writing means for storing, in the memory, data input from the host device via the primary USB interface;
A USB memory device comprising: reading means for reading data stored in the memory and outputting the data to the host device via the primary USB interface;
The USB memory device according to claim 1, wherein the writing means includes distributed storage means for storing data input from the host device in the plurality of memories in a predetermined unit.   The USB memory device according to claim 11, wherein the distributed storage unit causes each memory to perform processing for storing data input from the host device in each memory in parallel.   13. The read unit according to claim 11, further comprising: a distributed read unit that reads the data distributed and stored in the plurality of memories by the distributed storage unit and outputs the data to the host device. USB memory device.   14. The USB memory device according to claim 11, further comprising a FIFO memory that can temporarily store data received from the host device and to be stored in the memory. The writing means has continuous storage means for storing data input from the host device in the memory in a continuous state;
15. The storage system selecting means for selecting whether the data input from the host device is stored by the distributed storage means or by the continuous storage means. The USB memory device according to claim 1.   The continuous storage means stores the data input from the host device in one of the plurality of memories in a continuous state, and when the remaining capacity of the memory is exhausted, the continuation of the data 16. The USB memory device according to claim 15, wherein the memory is stored in a continuous state in another memory of the plurality of memories.   The USB memory device according to claim 1, wherein the predetermined unit is a minimum writing unit of the memory.   The USB memory device according to claim 1, wherein the memory is a flash memory. A host device with a USB interface that can connect multiple slave devices in a daisy chain is readable.
Write means for storing data in the memory of a plurality of USB memory devices connected in a daisy chain from the USB interface or a USB interface of another slave device connected in a daisy chain to the USB interface;
A USB memory device control program for causing the host device to implement a reading means for reading data stored in the memory,
The USB memory device control program characterized in that the writing means has distributed storage means for performing control to distribute and store data in predetermined units in the memories of the plurality of USB memory devices.   20. The USB memory device control program according to claim 19, wherein the distributed storage means causes each USB memory device to perform processing for storing data in the memory of each USB memory device in parallel.   21. The USB memory device control according to claim 19, wherein the reading unit includes a distributed reading unit that reads data stored in a distributed manner in the memories of the plurality of USB memory devices by the distributed storage unit. program. The writing means has continuous storage means for storing data in a continuous state in one of the plurality of USB memory devices,
22. The storage device selection unit for selecting whether to store data by the distributed storage unit or the continuous storage unit is implemented in the host device. The USB memory device control program according to one item.   The continuous storage means stores the data in a continuous state in one of the plurality of USB memory devices, and when the remaining capacity of the memory is exhausted, the continuation of the data is 23. The USB memory device control program according to claim 22, wherein the USB memory device is stored in a continuous state in a memory of another USB memory device.   The USB memory device control program according to any one of claims 19 to 23, wherein the predetermined unit is a minimum writing unit of the memory.   The USB memory device control program according to any one of claims 19 to 24, wherein the memory is a flash memory.

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