JPH07334316A - External storage device for computer - Google Patents

Abstract

PURPOSE:To provide the external storage device for the computer which is suitable for the use of a memory card as a recording medium for the computer. CONSTITUTION:The external storage device 2 is equipped with a host interface part 4 which is connected to the host computer H, a card slot 6 wherein plural memory cards C1-Cn are mounted, a control circuit 8, and a DRAM memory 10, and the CPU 12 in the control circuit 8 controls a card control part 14 and a memory control part 18 at a write and a read request from the computer H to transfer data between the memory cards C1-Cn and computer H and also store the data temporarily in a DRAM memory 10. When data which are written or read by the computer H last time are requested to be read out this time, the data are transferred from the DRAM memory 10 to the computer H. Consequently, the data can be transferred faster.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an external storage device connected to a computer.

[0002]

2. Description of the Related Art Conventionally, a card-shaped memory card (IC card) having a semiconductor memory IC has been put into practical use as a recording medium of a computer. A so-called notebook personal computer is provided with a card slot for mounting a memory card in advance, and a so-called desktop personal computer is
A memory card can be used by additionally providing a dedicated expansion board.

[0003]

However, since the notebook personal computer and the expansion board have only one or two card slots, there is a problem that a large amount of data cannot be stored. is there.

As a countermeasure against this, efforts are being made to improve the semiconductor memory to increase the memory capacity per memory card, but the memory capacity of about 10 to 20 MB (megabyte) is still the limit. Be done. Therefore,
When a memory card was used as a recording medium for a computer, it was not possible to store a large amount of data.

The present invention has been made in view of these problems, and an object thereof is to provide an external storage device of a computer suitable for using a memory card as a recording medium of the computer.

[0006]

That is, the present invention as set forth in claim 1 made in order to achieve the above object, is equipped with an interface connected to a computer and a semiconductor memory as illustrated in FIG. Data is transferred between the computer and the memory card mounted in the card slot, the card slot in which a plurality of memory cards are detachable, the storage unit for storing predetermined data, and the memory card mounted in the card slot. Transfer means for causing the storage means to temporarily store the data transferred by the transfer means in the storage means, and a write request of data from any one of the memory cards inserted in the card slot from the computer, Write control means for causing the transfer means to transfer the data from the computer to the memory card; When there is a data read request from the computer to any of the memory cards mounted in the card slot, it is determined whether or not the data corresponding to the request is stored in the storage means, and the data is stored. Read control means for causing the transfer means to transfer data from the memory card to the computer if the transfer means is not stored, and for causing the transfer means to transfer data from the storage means to the computer if the data is stored. An external storage device of a computer is provided as a gist.

According to a second aspect of the present invention, in the external storage device of the computer according to the first aspect, the same data is transferred from the computer to any two memory cards mounted in the card slot. When there is a request to write, the write control means causes the transfer means to transfer the data from the computer to one of the two memory cards, and at the same time from the storage means to the two memory cards. The gist is an external storage device of a computer, which is characterized in that data is transferred to the other memory card.

According to a third aspect of the present invention, in the external storage device of the computer according to the first or second aspect, the memory card has an interface connectable to another device, An external storage device of a computer is characterized in that the write control unit and the read control unit control data transfer by the transfer unit between a device connected to the memory card and the computer.

Next, the present invention according to claim 4 is the external storage device of the computer according to any one of claims 1 to 3, wherein there is a request to directly access the storage means from the computer. A storage area setting means for setting a predetermined storage area of the storage means as a dedicated area accessible to the computer; and a data write request to the storage means from the computer, the data from the computer is dedicated to the storage area setting means. An external storage device for the computer, further comprising: second transfer means for transferring the data to the area and for transferring the data from the dedicated area to the computer when there is a data read request from the computer to the storage means. Is the gist.

According to a fifth aspect of the present invention, in any one of the external storage device of the computer according to any one of the first to fourth aspects, any one of the ones mounted from the computer to the card slot is used. When there is a request to copy data from one memory card to another memory card, the data is transferred from the one memory card to the storage means, and after the data transfer, from the storage means to the other memory card. An external storage device of a computer is characterized in that a third transfer means for transferring data is provided.

[0011]

In the external storage device of the computer according to claim 1 configured as described above, the transfer means is a memory connected to the computer connected to the interface and a memory detachably attached to the card slot. Data is transferred to and from the card via the interface, and the storage means temporarily stores the data transferred by the transfer means in the storage means.

When there is a request from the computer to write data to any of the memory cards mounted in the card slot via the interface, the write control means causes the transfer means to transfer the data from the computer to the memory card. Transfer to. Then, the storage means
The transferred data is temporarily stored in the storage means.

Further, when a data read request is issued from the computer to any one of the memory cards mounted in the card slots via the interface, the read control means first causes the data corresponding to the request to be stored in the storage means. It is determined whether or not the data is stored, and if the data is not stored, the transfer means transfers the data from the memory card that has issued the read request to the computer.
Then, also in this case, the storage means temporarily stores the transferred data in the storage means. On the other hand, when the read control unit determines that the data corresponding to the read request from the computer is stored in the storage unit, the read control unit causes the transfer unit to transfer the data from the storage unit to the computer.

That is, in the external storage device of the computer according to the first aspect, data transfer between the computer and the memory card mounted in the card slot is executed in response to a write request and a read request from the computer. At the same time, the transferred data is stored in a temporary storage means, and when this data is requested to be read from the computer, that is, the data previously written to any memory card from the computer or the previous time from any memory card to the computer. When the data read out to the computer is requested to be read this time, the data is transferred not from the memory card but from the storage means to the computer.

As described above, according to the external storage device of the computer according to the first aspect, since a plurality of memory cards can be used as the recording medium, even if the storage capacity per memory card is small. , Large amount of data can be stored using memory card. And since memory cards do not require mechanical parts like when using a floppy disk or hard disk as a recording medium, they are excellent in vibration resistance and shock resistance, and data can be accessed at high speed when accessed from a computer. Can be transferred.

Further, in the external storage device of the computer according to the first aspect, the data to be transferred in response to the write or read request from the computer is temporarily stored in the storage means, and when there is a read request from the computer, When the data corresponding to the request is stored in the storage means, the data is directly transferred from the storage means to the computer, not from the memory card.

Therefore, according to the external storage device of the computer described in claim 1, data can be transferred at a higher speed in response to a read request from the computer. Next, in the external storage device of the computer according to claim 2, in the external storage device of the computer according to claim 1, the write control means transfers from the computer to any two memory cards mounted in the card slots. When there is a request to write the same data, the transfer means is caused to transfer the data from the computer to one of the two memory cards and to transfer the data from the storage means to the other memory card. There is.

That is, when the transfer means transfers the data from the computer to one of the memory cards, the data is temporarily stored in the storage means. Therefore, in the external storage device of the computer according to claim 2, the computer transfers the card to the card. When there is a request to write the same data to any two memory cards installed in the memory slots, first, the data from the computer is transferred to one memory card, and the storage means is transferred to the other memory card. I am trying to transfer data from.

Therefore, according to the external storage device of the computer of the second aspect, the data can be written in the two memory cards by the computer only outputting the data once. Next, in the external storage device of the computer according to claim 3, in the external storage device of the computer according to claim 1 or 2, a memory card having an interface connectable to another device in the card slot. When is mounted, the write control means and the read control means control the data transfer by the transfer means between the computer connected to the memory card and the computer.

In other words, a memory card currently in practical use that is compliant with JEIDA (Japan Electronic Industry Development Association) Ver4.1, which is the standard, is for connecting the memory card itself to the telephone line. RS-232C, which is a communication interface with electronic devices such as a modem (modulator / demodulator) and printer, and SCSI (Small Computer System Interface), which is an interface with storage devices such as a hard disk drive and a CD-ROM drive.
Interface functions such as are added.

Therefore, in the external storage device of the computer according to claim 3, the card slot is provided with the JEIDA standard.
When a Ver4.1 memory card is installed and a device such as a telephone line or a hard disk drive is connected to the memory card, the write control means and the read control means,
The data transfer by the transfer means between the device connected to the memory card and the computer is controlled. Therefore, according to the external storage device of the computer described in claim 3, the connection between the computer and the other device can be easily realized by the device.

On the other hand, in the external storage device of the computer according to claim 4, when there is a request from the computer to directly access the storage means, the storage area setting means causes the computer to access a predetermined storage area of the storage means. Set as a possible private area. Then, the second transfer means transfers the data from the computer to the set dedicated area when the computer issues a data write request to the storage means, and also issues the data read request from the computer to the storage means. , Transfer data from its dedicated area to the computer.

Therefore, according to the external storage device of the computer according to the fourth aspect, the computer can directly access the storage means, and higher speed data transfer can be realized. Further, in the external storage device of the computer according to claim 5, when there is a request from the computer to copy data from any one memory card mounted in the card slot to another memory card, The transfer means 3 transfers the data from the one memory card to the storage means, and after the data transfer, transfers the data from the storage means to another memory card.

Therefore, according to the external storage device of the computer according to the fifth aspect, if the computer outputs a request to copy the data from one memory card to another memory card, then the computer and The data stored in one memory card can be copied to another memory card when the device is disconnected (offline state). And the computer is
While the data is being copied between the memory cards, another process can be executed.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an external storage device of a computer of an embodiment to which the present invention is applied (hereinafter, simply referred to as an external storage device)
Will be described. The external storage device 2 of the present embodiment has a hard disk drive (hereinafter, referred to as a hard disk drive) as shown in FIG. 2 showing its schematic structure and FIG.
S, which is a typical interface of HDD)
CSI and IDE (Intelligent Drive Electronics or
Integrated Device Electronics)
A host interface unit 4 as an interface for interpreting the protocol and commands, a card slot 6 into which a plurality of memory cards C1 to Cn are detachably mounted, and a computer H connected via the host interface unit 4. Control circuit 8 for controlling the data transfer between the memory card C1 to the memory card C1 mounted in the card slot 6, and a DRAM as a storage means for temporarily storing the data handled by the control circuit 8.
A (dynamic RAM) memory 10 is provided.

Here, the host interface section 4 is connected to the HDD connection section provided in the computer H. The card slot 6 is composed of a plurality of slots for mounting memory cards individually, and each slot has an interface for supporting memory cards of JEIDA standard Ver4.0 or later. The DRAM memory 10 is a so-called SIMM (Single Inline Memory Module) in which a plurality of DRAM semiconductor chips are mounted on an elongated printed circuit board having connector terminals on one side.
It has the structure of.

On the other hand, the control circuit 8, as shown in FIG.
Access via the card slot 6 by controlling the CPU 12 that controls each unit that configures the circuit according to various requests input via the card, and the card slot 6 according to a command from the CPU 12. A card controller 14 for setting possible memory cards C1 to Cn and their addresses, an SRAM (static RAM) memory 16 for storing information on data written in the DRAM memory 10 as described later, and a command from the CPU 12 Accordingly, the host interface unit 4 (computer H), the card slot 6 (memory cards C1 to C)
n), the DRAM memory 10, the SRAM memory 16, and the CPU 12, and a memory control unit 18 as a transfer unit for transferring data.

In the external storage device 2 thus configured, the CPU 12 in the control circuit 8 executes each process described later in response to a request from the computer H, so that the memory card C1 to C1 by the computer H is executed. The writing and reading of data to and from Cn, the caching function by the DRAM memory 10 at the time of reading, the mirroring function for performing the mirroring for writing the data from the computer H to the two memory cards, and the computer H using the DRAM memory 10 as the RAM A RAM disk function for use as a disk, a copy function for copying data between two memory cards, and a memory card compliant with JEIDA standard Ver4.1 in the card slot 6, that is, with another device. Memory with interface function If the over-de is mounted, and realize the function of controlling the data transfer between the connected device and computer H to the memory card.

Therefore, first, regarding the writing / reading processing executed by the CPU 12 in order to realize the writing and reading of data to and from the memory cards C1 to Cn by the computer H and the caching function of the DRAM memory 10 at the time of reading. , FIG. 4 will be described.

When writing data to any of the memory cards C1 to Cn mounted in the card slot 6, the computer H has a slot on the card slot 6 in which a memory card to which data is to be written is mounted. The number (hereinafter, simply referred to as a slot) and the address on the memory card where the data is written are output to the device together with the write request. Similarly, the computer H
When reading data from any of the memory cards C1 to Cn mounted in the card slot 6, a read request is made for the slot of the memory card from which the data should be read and the address on the memory card in which the data is stored. And output to the device.

As shown in FIG. 4, when the writing / reading process is started, first, in step (hereinafter, simply referred to as S) 110, the computer H loads one of the memory cards C1 to Cn. On the other hand, it is determined whether or not there is a data write request. If it is determined that a write request has been issued, then in step S120, the slot of the memory card for which the write request has been made and the address on the memory card in which the data should be written are acquired from the host interface unit 4, and then step S130 Then, the obtained slot and address of the memory card are output to the card controller 14. Then, the card control unit 14 outputs the slot and the address to the card slot 6, and a storage area (hereinafter, referred to as a writing area) corresponding to the address of the memory card mounted in the slot is a card slot. 6 is set so that it can be accessed.

Then, in subsequent S140, the data input from the computer H via the host interface unit 4 is transferred to the write area of the memory card for which the write request is made and the DRAM memory 10, respectively. In this data transfer, the memory controller 18 causes the data from the computer H to be transferred to the card slot 6, and at the same time, the data is written to the DRAM memory 10 as a write control means and a storage means. Executed by. Then, by this processing, the computer H
The data from is written in the memory card (write area of the memory card which is set to be accessible by the card control unit 14) for which a write request has been made and the DRAM memory 10.

When the data transfer is completed in S140, the information about the data written in the DRAM memory 10 is transferred to the SRAM memory 1 in the subsequent S150.
6, and then returns to S110. The information recorded in the SRAM memory 16 represents that the data written in the DRAM memory 10 is the same as the data written in which address of which memory card. In the flag prepared inside, S
It is recorded by writing the slot and address of the memory card acquired in 120.

On the other hand, when it is determined in S110 that there is no write request from the computer H, the process proceeds to S160, and this time, the computer H issues a data read request to one of the memory cards C1 to Cn. It is determined whether or not there is. If it is determined that there is no read request, the process returns to S110, and if it is determined that there is a read request, the process proceeds to S170.

In S170, as in S120,
The slot of the memory card for which the read request has been made and the address on the memory card in which the data to be read are stored are acquired from the host interface unit 4, and then S18
At 0, it is determined whether the data corresponding to the slot and address of the memory card acquired in S170 is stored in the DRAM memory 10. In addition, this determination is S1
This is performed by comparing the slot and address of the memory card acquired in 70 with the slot and address of the memory card written in the flag in the SRAM memory 16, and if both match, the read request is made this time. An affirmative decision is made that the data in the memory card is in the DRAM 10 memory, and a negative decision is made if the two do not match.

When a negative determination is made in S180,
That is, if it is determined that the data corresponding to the slot and address of the memory card acquired in S170 is not stored in the DRAM memory 10, the card control unit 14 continues to S190 in which the slot of the memory card acquired in S170 and Output address. Then, as in the case of S130, the card control unit 14 outputs the slot and address to the card slot 6, and the storage area (hereinafter, read area) corresponding to the address of the memory card mounted in the slot. Is a card slot 6
To be accessible via.

Then, in subsequent S200, the data stored in the read area of the memory card for which the read request is issued is transferred to the computer H and the DRAM memory 10, respectively. Note that this data transfer is performed by the memory control unit 18
The data stored in the read area of the memory card for which a read request is made is transferred to the computer H via the card slot 6 and the host interface unit 4, and at the same time, the data is transferred to the DRAM memory 10.
It is executed by the processing as the read control means and the storage means that is written in the. Then, by this processing, D
The same data as that of the memory card (the reading area of the memory card which is set to be accessible by the card control unit 14) for which the reading request is made is written in the RAM memory 10.

When the data transfer is completed in S200, information about the data written in the DRAM memory 10 is recorded in the SRAM memory 16 in S210, which is the same as in S150, and then in S1.
Return to 10. On the other hand, in S180, the DRAM memory 10
When it is determined that the data corresponding to the slot and address of the memory card acquired in S170 is stored in S170, the process proceeds to S220. Then, in S220, a command is issued to the memory control unit 18, and the DRAM memory 1
The data stored in 0 is transferred to the host interface unit 4
The process as the read control means for transferring the data to the computer H via the is executed, and the process returns to S110.

That is, in the writing / reading process, by controlling the card control unit 14 and the memory control unit 18 in response to the writing request and the reading request from the computer H, any one of the cards inserted into the card slot 6 is controlled. The data transfer between the memory cards C1 to Cn and the computer H, and the transferred data is temporarily stored in the DRAM.
The data is stored in the memory 10 (S140, S2
20). Then, when the data previously written from the computer H to any of the memory cards C1 to Cn or the data previously read from any of the memory cards C1 to Cn to the computer H is requested to be read this time (S180). : YES), data is transferred from the DRAM memory 10 to the computer H, not from the memory cards C1 to Cn (S220). That is, when writing and reading data between the computer H and the memory cards C1 to Cn, the DRAM memory 10
Is used as a so-called cache memory.

Therefore, according to the external storage device 2 of the present embodiment, the computer H can use the plurality of memory cards C1 to Cn as recording media, so that the storage capacity per memory card C1 to Cn is one. Even if it is small, it can store a large amount of data. Since the memory cards C1 to Cn do not require any mechanical parts, they are excellent in vibration resistance and shock resistance, and can transfer data at high speed when accessed by the computer H.

Moreover, in the external storage device 2 of this embodiment,
Using the DRAM memory 10 as a cache memory,
When the computer H issues a read request for the same data as the previously written data or the previously read data, the data is directly transferred from the DRAM memory 10 to the computer H. Therefore, it is possible to realize higher-speed data transfer with the computer H.

Next, the mirroring process executed by the CPU 12 to realize the mirroring function of writing the data from the computer H into the two memory cards will be described with reference to FIG. This mirroring process is
This is executed when the computer H previously designates two memory cards for performing mirroring (that is, the slots of the memory card for performing mirroring) to the device. First, at S310, the memory is designated by the computer H. It is determined whether or not there is a data write request to either one of the two memory cards.

Then, until there is a write request, this S3
When it is determined that there is a write request by waiting at 10, the slot of the memory card for which the write request is made and the address on the memory card where the data should be written are acquired from the host interface unit 4 at S320. . Then, in subsequent S330, the acquired slot and address of the memory card are output to the card control unit 14, and the card control unit 14 is loaded into the slot in exactly the same manner as in S130 in the writing / reading process. The storage area (writing area) corresponding to the above address of the memory card is set so as to be accessible through the card slot 6.

Then, in subsequent S340, the data input from the computer H via the host interface unit 4 is transferred to the above-mentioned writing area of the memory card having the writing request and the DRAM memory 10, respectively. Note that this data transfer causes the memory control unit 18 to transfer the data from the computer H to the card slot 6 in the same manner as in the case of S140 in the writing / reading process, and at the same time, the data is transferred to the DRAM memory. This is executed by the processing as the write control means and the storage means that causes the data to be written in the memory 10. Then, by this processing, the computer H
The data from (1) will be written to one of the memory cards designated for mirroring and the DRAM memory 10.

Then, in subsequent S350, just like S150 in the writing / reading process, the DRAM memory 10
The information about the data written in is stored in the SRAM memory 16, and the process proceeds to S360. In S360, the slot of the other memory card designated to be mirrored and the same address as the address acquired in S320 are output to the card control unit 14. Then, the card control unit 14 sets the other memory card so that the storage area (writing area) of the same address as the memory card to which the data is written in S340 can be accessed.

Then, in the subsequent S370, the memory controller 18 is instructed to transfer the data stored in the DRAM memory 10 to the writing area of the other memory card through the card slot 6. The process as the write control unit is executed, and then the process returns to S310.

Then, exactly the same data is written in the write areas of the same address in the two memory cards designated to perform the mirroring. In other words, by executing this mirroring process, the computer H can write the data into the two memory cards by outputting the data only once.

When the computer H issues a write request to a memory card other than the memory card designated to perform the mirroring, or a read request to the memory card designated to perform the mirroring. In that case, no special processing is executed, and the writing / reading processing shown in FIG. 4 is executed.

Next, the computer H sets the DRAM memory 1
Regarding the processing executed by the CPU 12 to realize the RAM disk function of using 0 as a RAM disk,
This will be described with reference to FIG. As shown in FIGS. 6A and 6B, this process is executed when the computer H requests the device to use the DRAM memory 10 as a RAM disk. A RAM disk area setting process and a RAM disk area releasing process which is executed when there is a request from the computer H to finish using the DRAM memory 10 as a RAM disk;
Consists of.

Therefore, first, the RAM disk area setting process will be described. In this RAM disk area setting process, first, in S410, the computer H
It is determined whether or not there is a request to use the memory 10 as a RAM disk, and if there is a request, the following processing is executed.

That is, in subsequent S420, a process as a storage area setting means for setting a partial storage area of the DRAM memory 10 as a dedicated area (hereinafter referred to as a RAM disk area) directly accessible by the computer H is executed. Note that this processing is performed by causing the memory control unit 18 to allocate a predetermined area of the DRAM memory 10 as a RAM disk area.

Then, in subsequent S430, which storage area of the DRAM memory 10 is set as the RAM disk area is recorded in the SRAM memory 16, and the subsequent S4 is executed.
At 40, the RAM disk (DRA
It waits until there is a data transfer request to the M memory 10).

When there is a data transfer request, S45
In step S460, it is determined whether or not the request is a write request. If the request is a write request, the data input from the computer H via the host interface unit 4 is subjected to memory control in S460. D through section 18
A process as a second transfer means for transferring to the RAM disk area of the RAM memory 10 is executed. Then, the data from the computer H is written in the RAM disk area, and after this process, the process returns to S440.

On the other hand, if it is determined in S450 that the data transfer request from the computer H is not a write request, that is, a read request, the process proceeds to S470,
A process as a second transfer unit that transfers data from the RAM disk area of the DRAM memory 10 to the computer H via the memory control unit 18 and the host interface unit 4 is executed, and then the process returns to S440.

That is, in this RAM disk area setting process, the DRAM memory 10 is transferred from the computer H to the RAM.
If there is a request to use it as a disc (S410:
YES), a partial area of the DRAM memory 10 is set as a RAM disk area (S420), and thereafter, when the computer H makes a data write request to the RAM disk, the data from the computer H will be DRAM.
Write to the RAM disk area of the memory 10 (S46
0), when there is a request from the computer H to read data from the RAM disk, RA of the DRAM memory 10
Data is read from the M disk area and transferred to the computer H (S47).
0).

Therefore, according to the external storage device 2 of this embodiment, the computer H can directly access the DRAM memory 10 as a RAM disk.
Higher speed data transfer can be realized. Incidentally, R
In S430 of the AM disk area setting process, which storage area of the DRAM memory 10 is R is stored in the SRAM memory 16.
What is set as the AM disk area is recorded in the above-mentioned write / read processing (S140, S).
200) and the mirroring process (S340),
This is to show that data cannot be written in the portion of the DRAM memory 10 set as the RAM disk area, which prohibits the use of the RAM disk area as a cache memory.

Further, the RAM disk area set in this way is stored in the R area of the DRAM memory 10 from the computer H.
Request to end use as an AM disk (hereinafter,
When there is a release request), it is returned to the normal storage area. Therefore, next, the RAM disk area releasing process for returning the RAM disk area to the normal storage area will be described.

This RAM disk area release processing is performed by RA
Although it is executed in parallel with the M disk area setting process, as shown in FIG. 6B, when it is determined in S510 that the computer H has issued a release request, the following substantial process is performed. To be executed. That is, when there is a release request from the computer H, in the subsequent S520, the DRA
The RAM disk area in the M memory 10 is returned to the normal storage area, and in the subsequent S530, the contents recorded in the SRAM memory 16 in S430 of the RAM disk area setting process are rewritten. That is, the fact that the area of the DRAM memory 10 set as the RAM disk area can be used as the cache memory is recorded in the SRAM memory 16, and then the process returns to S510.

When the RAM disk area releasing process is executed once, the computer H restarts the DRA operation.
There is a request to use the M memory 10 as a RAM disk, and the use of the DRAM memory 10 as a RAM disk is stopped until a positive determination is made in S410 of the RAM disk area setting process.

Next, a copy process executed by the CPU 12 to realize a copy function for copying data between two memory cards will be described with reference to FIG.
When copying data between two memory cards, the computer H issues a copy command to the slot of the source memory card that is the copy source and the slot of the destination memory card that is the copy destination. And output to the device.

As shown in FIG. 7, in this copy process,
First, in S610, it is determined whether or not a copy command is output from the computer H. Then, when it is determined that the copy command is received, the respective slots of the source side memory card and the destination side memory card output from the computer H together with the copy command are acquired, and the process proceeds to S620.

In S620, the slot of the memory card on the source side is output to the card control unit 14, and the card control unit 1
4 is set so that the source side memory card can be accessed through the card slot 6. Then, in subsequent S630, 1 stored in the memory card on the source side is stored.
A block (for example, 512 bytes) of data is transferred to the DRAM memory 10 via the card slot 6 and the memory control unit 18, and a process as a third transfer unit is executed, and the process proceeds to S640. Note that in S630, each time the processing is executed, one block of data is sequentially read from the source side memory card and transferred to the DRAM memory 10.

In S640, this time, the slot of the destination side memory card is output to the card control section 14 so that the destination side memory card can be accessed through the card slot 6. To set. Then, in subsequent S650, S
The data stored in the DRAM memory 10 in the process of 630 is transferred to the destination side memory card through the memory control unit 18 and the card slot 6, and the process as the third transfer means is executed. Then, it is determined whether or not the copying of all the data stored in the source side memory card is completed.

If it is determined that the copying of all the data has not been completed, the process returns to S620 and S620 to S620.
When it is determined that the copying of all the data is completed by repeating the processing of 660, the process returns to S610. In other words, in this copy processing, by reading the data for one block from the source side memory card, writing it once in the DRAM memory 10 (S630), and writing the data in the destination side memory card (S650), the processing is repeated. , All data in the source memory card is copied to the destination card.

Therefore, according to the external storage device 2 of the present embodiment, when the computer H outputs the copy command, thereafter, the computer H and the device are disconnected from each other (offline state), and the source side memory is obtained. Since the data in the card can be copied to the destination side memory card, the computer H can execute other processing while the data is being copied between the two memory cards.

Further, the CPU 12 executes S of this copy processing.
If there is another request (access to any memory card, etc.) from the computer H during the execution of 620 to S660, the execution of the copy process is temporarily stopped, and the process corresponding to the request is preferentially executed. After the end of the processing, the copy processing is restarted. Therefore, the computer H can proceed with other processing by prioritizing the data copy between the two memory cards.

Here, each of the processes described above with reference to FIGS. 4 to 7 was performed when the memory card intended only for storing data was mounted in the card slot 6. Therefore, in the following, the JEIDA standard is used for the card slot 6.
When a memory card conforming to Ver4.1, that is, a memory card having an interface function with another device is attached, the CPU 12 controls the data transfer between the device connected to the memory card and the computer H. The processing executed by will be described.

First, when a memory card connectable to a telephone line (hereinafter, referred to as a modem card) like the memory card denoted by reference numeral C3 in FIG. 3 is mounted in the card slot 6, FIG. The background transmission / reception processing as the write control means and the read control means shown in is executed.

This background transmission / reception processing is executed in order to efficiently connect the computer H and the telephone line via the modem card mounted in the apparatus. First, in S710, for the card. Slot 6
The computer H connects the telephone line to any one or more of the other memory cards (for example, an inexpensive RAM card that loses data when the card is inserted into or removed from the card slot 6) that does not have an interface function. It is assigned as a transmission / reception memory card for temporarily storing data to be transmitted / received via. Hereinafter, this allocated memory card will be referred to as an allocation card.

Then, in the following S720, it is determined whether or not there is a transmission request from the computer H indicating that the data is to be transmitted to the telephone line. If there is a transmission request, then in the following S730, the computer H transmits the data. The transmission data output together with the transmission request is written in the allocation card. Note that the transmission data is written to the allocation card in the same manner as in S120 to S140 of the writing / reading process described above, the card control unit 1
4 is set so that the assigned card can be accessed through the card slot 6, and the memory control unit 18 transfers the transmission data from the computer H to the card slot 6.

Then, in step S740, whether or not the file name (transmission file name) of the data to be transmitted to the telephone line and the telephone number of the transmission destination are output from the computer H is checked via the host interface unit 4. When the transmission file name and the telephone number are received, the process proceeds to S750.

In S750, the memory control unit 18 is set so that data can be directly transferred between the allocation card and the modem card, and in the subsequent S760, the modem card is accessed to make a call. Then, in the following S770, it is determined whether or not the data can be transferred by calling the destination, and S760, 77 until the data can be transferred.
The process of 0 is repeated.

When it is determined in S770 that the data transfer is possible, the process proceeds to S780, in which the data corresponding to the transmission file name from the data stored in the allocation card is stored in the memory controller 18 as the modem card. Transfer to. Then, the data is sent to the telephone line via the modem card and reaches the destination.

Then, in the following S790, it is determined whether or not the data transfer is completed, and until the data transfer is completed,
The processing of S780 and 790 is repeated. And S790
When it is determined that the data transfer is completed, the process proceeds to S800, the modem card is accessed to close the telephone line,
In subsequent S810, the computer H is notified that the communication is completed, and then the process returns to S720.

On the other hand, if it is determined in S720 that there is no transmission request from the computer H, the process proceeds to S820, and it is determined whether the modem card has detected a telephone call. Then, if the telephone call is not detected by the modem card, the process returns to S720, and if the telephone call is detected, the process proceeds to S830.

In S830, as in the case of S750,
The memory control unit 18 is set so that data can be directly transferred between the modem card and the allocation card, and in the subsequent S840, the reception file is set in the allocation card. And
In subsequent S850, the modem card is accessed to receive the call, and in subsequent S860, it is determined whether or not the data can be transferred through the telephone, and the data transfer can be performed in S850 and S860. Repeat the process.

When it is determined in S860 that the data transfer is possible, the process proceeds to S870 and the memory control unit 18 is caused to transfer the data from the modem card to the reception file set in the allocation card. Then, the data transmitted from the telephone line is stored in the reception file of the allocation file.

Then, in subsequent S880, it is determined whether or not the data transfer is completed, and until the data transfer is completed,
The processes of S870 and S880 are repeated. And S88
When it is determined that the data transfer is completed at 0, S890
Then, in step S900, the computer H is notified of the reception and the file name for reception of the allocation card in which the reception data is stored. Return to S720.

That is, in this background transmission / reception processing, the data to be transmitted to the telephone line is stored in the allocation card other than the modem card (S730), and the transmission file name and the transmission destination telephone number are output from the computer H. Then, (S740: YES), the data corresponding to the transmission file name is transferred from the allocation card to the modem card, and the data is transmitted to the destination (S).
750-S810). When a call is received via the modem card (S820: YES), the data received by the modem card is transferred to the receiving file of the allocation card (S).
830 to S890), the computer H is notified of only the reception and the reception file name (S900).

Therefore, from the side of the computer H, all the data transmission / reception performed via the telephone line is processed in the background by the device, and the computer H transmits / receives the data via the telephone line. In the meantime, you will be able to run other applications.

Next, a memory card that can be connected to the HDD, such as the memory card denoted by Cn in FIG.
When a SCSI card) is attached to the card slot 6, the CPU 12 executes a process for connecting the HDD connected to the SCSI card to the computer H. And this processing is performed by the H from the computer H.
When the access request to the DD is received, the card control unit 14 and the memory control unit 18 cause the host interface unit 4 and the S
It is executed by the procedure of controlling so that the data can be directly transferred to and from the CSI card.

Then, the computer H can handle the HDD connected to the SCSI card as one of the memory cards mounted in the card slot 6. In other words, the SCSI card to which the HDD is connected is treated by the computer H as if it were a memory card having the storage capacity of the HDD.

As described in detail above, according to the external storage device 2 of this embodiment, the computer H can access a plurality of memory cards C1 to Cn and store a large amount of data. Moreover, DRAM memory 1
Using 0 as cache memory, the computer H
It is possible to realize higher-speed data transfer in response to a read request from the.

Further, by the mirroring process using the DRAM memory 10 (FIG. 5), the computer H can write the data into two memory cards by outputting the data only once, and the RAM disk area setting can be performed. The process (FIG. 6) enables the computer H to directly access the DRAM memory 10 as a RAM disk. Then, by the copy processing shown in FIG. 7, the computer H can copy the data between the two memory cards only by outputting a copy command to the device, and during that time, the computer H does not copy other data. Processing can be performed.

On the other hand, in the external storage device 2 of the present embodiment, when a memory card conforming to the JEIDA standard Ver4.1 having an interface function with another device is attached to the card slot 6, the case shown in FIG. Since the background transmission / reception processing and the processing for connecting the HDD shown in (1) are executed, the external device connected to the memory card and the computer H can be connected easily and efficiently.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of the present invention.

FIG. 2 is a structural diagram showing a schematic structure of an external storage device of an embodiment.

FIG. 3 is a block diagram illustrating a configuration of an external storage device according to an embodiment.

FIG. 4 is a flowchart showing a writing / reading process executed by a CPU of an external storage device.

FIG. 5 is a flowchart showing a mirroring process executed by a CPU of an external storage device.

FIG. 6 is a flowchart showing a RAM disk area setting process and a RAM disk area releasing process executed by the CPU of the external storage device.

FIG. 7 is a flowchart showing a copy process executed by a CPU of an external storage device.

FIG. 8 is a flowchart showing background transmission / reception processing executed by a CPU of an external storage device.

[Explanation of symbols]

2 ... External storage device 4 ... Host interface unit
6 ... Card slot 8 ... Control circuit 10 ... DRAM memory 1
2 ... CPU 14 ... Card control unit 16 ... SRAM memory 18
Memory controller C1 to Cn Memory card H Computer

Claims (5)

[Claims] 1. An interface connected to a computer, a card slot in which a plurality of memory cards each having a semiconductor memory mounted therein are detachable, storage means for storing predetermined data, and the computer and the card slot. Transfer means for transferring data to and from the attached memory card via the interface, storage means for temporarily storing the data transferred by the transfer means in the storage means, and the card slot from the computer When there is a data write request to any of the memory cards attached to the memory card, write control means for causing the transfer means to transfer the data from the computer to the memory card, and the computer is attached to the card slot from the computer. Need to read data to any memory card When there is a request, it is determined whether or not the data corresponding to the request is stored in the storage means, and if the data is not stored, the transfer means transfers the data from the memory card to the computer. An external storage device for a computer, comprising: read control means for causing the transfer means to transfer the data from the storage means to the computer when the data is stored. 2. The external storage device of the computer according to claim 1, wherein when there is a request from the computer to write the same data to any two memory cards installed in the card slot, the writing is performed. The control means causes the transfer means to transfer the data from the computer to one of the two memory cards and the data from the storage means to the other memory card of the two memory cards. An external storage device of a computer characterized by the following. 3. The external storage device of the computer according to claim 1, wherein the memory card includes an interface connectable to another device, and the write control unit and the read control unit include: An external storage device for a computer, wherein data transfer by the transfer means between a device connected to the memory card and the computer is controlled. 4. The external storage device for a computer according to claim 1, wherein a predetermined storage area of said storage means is set when a direct access from said computer is made to said storage means. Storage area setting means for setting as a dedicated area accessible by the computer; and, when there is a data write request from the computer to the storage means, data from the computer is transferred to the dedicated area, and the storage means from the computer And a second transfer means for transferring data from the dedicated area to the computer when there is a request to read data from the external storage device of the computer. 5. The external storage device of the computer according to claim 1, wherein data is transferred from the computer to the other memory card from any one memory card installed in the card slot. When there is a request to copy the data, the third transfer means for transferring data from the one memory card to the storage means and transferring the data from the storage means to the other memory card after the data transfer is performed. An external storage device of a computer, characterized by being provided.