JP2003281072A - Method and device for controlling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To have a device connected to a computer with an interface capable of inserting or extracting live wire easily to use. <P>SOLUTION: In a device controller for controlling the device connected to the computer with the interface capable of inserting or extracting live wire, a device address ADDR is attached to each device when the device is connected. Meanwhile, a virtual device address HDA different from the device address ADDR is set in each device. The virtual device address HDA is notified to an application, and designation is made with the virtual device address HDA when the application 50 uses the device 20. Meanwhile, even when the device is disconnected through the computer and is further reconnected, a new device address ADDRn to be newly assigned is linked with the virtual device address HDA, and the application 50 can access the device designated by the new device address ADDRn if the application 50 designates the virtual device address HDA. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device control method and apparatus for controlling a device connected to a computer by using a hot-pluggable interface.

[0002]

2. Description of the Related Art A computer is connected to various devices such as a hard disk device, an optical disk device, and a printer. In recent years, a USB interface has been widely used as an interface for connecting the computer and the device. A characteristic of the USB interface is a function called hot-plugging / unplugging, which allows devices to be connected and disconnected while the computer system is running. With this USB interface,
Up to 126 devices can be connected and used for one computer.

Further, the connector shapes of all devices connected using the USB interface are unified. Furthermore, data transfer of all USB devices is performed by time sharing the same protocol bus. Since the basic protocol for data transfer in all USB devices is the same, in order to give different meanings to the contents of data, it is necessary to process them with a software stack and add the concept of time.

For this reason, the data transfer method of the USB interface satisfies the above-mentioned requirements. Specifically, Interrupt transfer, Bulk transfer, Is
4 of Ochronous transfer and Control transfer
There are two transfer methods. Each device can realize optimum data transfer by selecting a transfer method suitable for the device characteristics. In particular, Control transfer is a transfer method used for exchanging information necessary for device control and the like, and is performed for all devices.

By the way, when a computer recognizes a device and puts it in a usable state, the device is recognized and managed by using a process called enumeration. Specifically, device recognition, device address allocation, and device configuration information reading are mainly performed.

First, the host responds to the default address on the device side to recognize the connection of the address. That is, the device address “0” is set in the buffer of the device in the initial state. On the other hand, the host responds to the device address "0". Therefore, the host can recognize the newly connected device.

Next, the device address is assigned. As described above, up to 127 devices can be connected to the host, and the host must be able to recognize each device. Therefore, the host
Assign device addresses that do not conflict with each device. Specifically, the host is 7 bit (0
Device addresses up to 127) can be assigned, and up to 127 devices including the host are recognized.

In addition, the host controls the device
A device request is sent by transfer to obtain device configuration information. The device has a descriptor describing the function of the device, and the descriptor is read in response to the device request. Then, the host acquires the vendor ID and the product ID together with the device configuration information described in the descriptor. Then, the host allocates the endpoint number based on the read configuration information.

Here, the endpoint means a buffer associated with the transfer method by the host controller. For example, a printer multifunction peripheral with a fax function has a printer function and a fax function in one device. The data and the transfer method to be handled are different for each of these functions. Therefore, the device side is provided with a buffer (FIFO) for each transfer, and the host side is provided with a function for identifying the transfer method for each buffer. The device buffer recognized on the host side is called an endpoint, and the number attached to the buffer is called an endpoint number.

Here, it is assumed that the device is already connected to the computer via the USB interface.
At this time, the host recognizes the device and assigns the device address. Therefore, the application running on the computer can access the device by designating the device address.

On the other hand, when the USB cable is pulled out from the USB connector on the computer side or the device side or the power source on the device side is turned off, the device cannot be accessed. In this state, if an application requests access to the device,
An error is output on the host side because the data is not transferred to the device. However, if the application does not access the device, the host will not output an error.

[0012]

If the device is reconnected to the computer without the application accessing the device, the host (computer) does not output an error, and the user disconnects the device. Recognize that you can use the device as before. However, even when the same device is reconnected, the host executes the enumeration mode described above to recognize the device. Here, the device address assigned to the same device by the host may be different from that assigned when the device was first connected. Then, even if the application tries to access the device by specifying the old device address, the device cannot be accessed. Therefore, when the device is reconnected, it takes time to search for the device to be accessed from the devices connected to the host, or the application causes an error.

As described above, even if the user can use the device under the same conditions as before the device is reconnected and disconnected, the device cannot be recognized on the computer unless the recognition work is performed on the computer. ing. That is,
There is a problem that the user interface cannot be achieved because the recognition by the user is different from the recognition on the computer.

Therefore, an object of the present invention is to provide a device control method and apparatus that make it easier to use a device connected to a computer by means of a hot-pluggable interface.

[0015]

A device control method of the present invention is a device control method for controlling a device connected to a computer by using a hot-swappable interface, when the device is connected to the computer. A step of obtaining device information from the device and assigning a device address for identifying the device to the device, and identifying the device when an application running on the computer uses the device. Assigning the virtual device address of the device to the device; creating an address table that links the virtual device address assigned to the device, the device address, and the device information; Access to the device, using the address table, converting the virtual device address included in the data sent from the application into the device address linked to the virtual device address and sending the device address. A step of retrieving the same device information from the address table using new device information newly acquired from the device when the device is disconnected from the computer and reconnected again; Updating the device address linked to the device information to the new device address when the device information identical to the new device address is present in the table.

Further, the device control apparatus of the present invention is a device control apparatus for controlling a device connected to a computer by using a hot-pluggable interface, recognizing that the device is connected to the computer. A device management unit that acquires device information from the device; an address setting unit that allocates a device address for identifying the device to the device when the device management unit recognizes the device; A virtual address setting unit that assigns a virtual device address for the application to identify the device when the application running on the device uses the device, the virtual device address assigned by the virtual address setting unit, and the address. When the device accesses the device, the address management unit that creates and stores an address table in which the device address assigned by the setting unit and the device information acquired by the device management unit are linked, Using the address table, the virtual device address included in the data sent from the application,
Address conversion means for converting the device address linked to the virtual device address and sending it to the device, wherein the address management means, when the device is disconnected from the computer and reconnected,
Using the new device information newly acquired from the device, search the same device information as the newly assigned new device information from the address table,
If the same device information as the new device address exists in the address table, the virtual device address remains the same and the device address linked to the device information is updated to the new device address. To do.

Here, "the device is connected to the computer" means that the device is connected in a state in which the computer can recognize it. Further, the “assignment of virtual device address” may be performed when the application is activated, or may be performed at the same time when the computer is activated.

Further, the "address table" may be stored in a buffer and created every time the computer is started, or the created address table may be stored in the computer and the same address table may be created each time the computer is started. May be used. The “device information” means information unique to each device for identifying the device connected to the computer.

[0019]

According to the device control method and apparatus of the present invention, when an application transfers data to a device, the device is disconnected once because it uses a virtual device address that does not change even if the device is reconnected to the computer. When the application is reconnected to the device, the seek time when the application attempts to access and use the device can be shortened or the occurrence of an error can be prevented, and the user interface can be improved.

By saving the created address table in the computer and using the same address table each time the computer is started, it is not necessary to assign a virtual device address each time the computer is started, and the virtual device address is not required. It is possible to reduce the processing for allocating the device address and the time.

[0021]

1 is a schematic diagram showing a configuration example of a device and a computer. In FIG. 1, the computer 1 and the device 20 are directly connected by a USB cable 10. If the device 20 is connected in a recognizable state when the computer 1 starts up, the device 20 is recognized and becomes usable when the computer 1 starts up. On the other hand, when the device 20 is connected while the computer 1 is running, the device is recognized in the computer 1 when the device 20 is connected. Then, the device is ready to use after the recognition is completed.

Although FIG. 1 illustrates the case where the device 20 is directly connected to the computer 1, when the plurality of devices 20 are connected to the computer 1, the computer 1 and the plurality of devices 20 are connected. Connected via a hub or a plurality of devices 20
Connect each other with a USB cable 10
May be connected to.

FIG. 2 shows a computer 1 and a device 20.
3 is a conceptual diagram showing a hierarchical structure in FIG. A host that controls the entire USB interface is configured in the computer 1 of FIG. 2, and the host is the bus interface 3
0, a device control device (logical device) 40, and an application 50 have three hierarchical structures. The bus interface 30 is a physical layer that transmits and receives data to and from the device 20, and is a SIE (Serial Interface Engine) that is connected to the USB cable 10.
ne) 31 is provided.

Device control device (logical device) 40
Is a layer of software that outputs data generated by the computer 1 to the bus interface 30 or processes data transmitted from the device 20. This software is run by the host controller of the bus interface and the CPU of the computer 1. The application 50 is a layer including application software that provides functions provided by various vendors, a device driver for controlling the operation of the device 20, and the like.

The device 20 is a bus interface 2
1, a USB logical device 22, and a function 23 have a hierarchical structure. The bus interface 21 is a physical layer that transmits / receives data to / from the computer 1, and is a SIE (Serial) connected to the USB cable 10.
l Interface Engine) 21 is provided. The logical device 22 is a layer that performs data input / output processing at the endpoint of the device 20. The function 23 is a layer that provides a function to the host, and by sending a script to the host side,
The host side can use the functions that the device can provide.

FIG. 3 is a block diagram showing a preferred embodiment of the device control apparatus of the present invention, and the device control apparatus 40 will be described with reference to FIG. The device control device 40 executes the program installed in the computer 1 or the host controller 32 on the computer 1
Realized by running on.

The device control device 40 comprises a device management means 41, an address setting means 42, a virtual address setting means 43, an application monitoring means 44, an address management means 46 and the like. The device management unit 41 sends various device requests to the device 20 connected to the computer 1 and receives a response from the device 20. Also, the device management means 41
Are for transmitting and receiving data packets to and from the bus interface 30 and for transferring data to and from the device 20. In particular, the device management means 41 is adapted to send information unique to the device 20 such as a vendor ID and a product ID (hereinafter referred to as “device information”) DI to the address management means 46 among the configuration information acquired from the device 20. .

Here, when the device management unit 41 transfers the control to the device 20, the token packet (Token Packet) as shown in FIG.
t) is sent. Even when data is transferred from the device management means 41 to the device 20, the token packet is sent before the data packet. The token packet in FIG. 4 includes a device address ADDR composed of a 7-bit (0 to 127) data string. The device 20 which is the same as the device address ADDR of the token packet responds to the token packet and data is transmitted and received.

The address setting means 42 is the computer 1
Device address ADDR to the device 20 connected to
Is to be set. Where device address AD
When setting the DR, the address setting means 42 uses the device address ADDR so that the devices 20 do not conflict with each other.
Are to be assigned. Further, the address setting means 42 sends the set device address ADDR to the address management means 46.

The virtual address setting means 43 has a function of assigning a virtual device address HDA for the application 50 to identify the device 20 when the application 50 uses the device 20. And
The virtual address setting means 43 sends the set virtual device address HDA to the address management means 46.

Here, in the conventional device control apparatus, the application 50 uses the device 20 by using the device address ADDR assigned by the address setting means 42. On the other hand, in the device control apparatus 40 of FIG. 3, the application 50 uses the virtual device address HDA to use the device 20. The virtual device address HDA is
For example, it has the same data length (7 bits) as the device address ADDR.

The application monitoring means 44 monitors the activation and termination of the application 50. In particular, the application monitoring unit 44 sends the virtual device address HDA stored in the address management unit 46, which will be described later, to the application 50 when the application 50 recognizes the activation. Then, the application 50 determines that the virtual device address HD
The device 20 is designated by A.

The address conversion means 45 has a function of performing address conversion processing on the data D1 sent from the application 50 via the application monitoring means 44, and sending it to the device management means 41. Specifically, the address conversion unit 45 converts the virtual device address HDA included in the data D1 into a device address ADDR and sends the device address ADDR to the device management unit 41.

Next, referring to FIG. 3, the address management means 4
6 will be described. The address management unit 46 receives the device information DI sent from the device management unit 41 and the device address ADD sent from the address setting unit 42.
An address table A that links R and the virtual device address HDA sent from the virtual address setting means 43.
It has a function of storing T. Therefore, as shown in FIG. 5, the address table AT shows the device address ADD.
R, device information DI and virtual device address HD
A is stored in a linked state.

The address table AT may be created by the device management means 41 every time the computer 1 is started up, or may be recorded in a storage device in the computer 1 such as a hard disk device and the computer 1 is restarted. Alternatively, the address table AT having the same content may be used.

The address management means 46 shown in FIG. 3 performs various operations in response to requests or data transfers from each component. First, the relationship between the address management means 46 and the device management means 41 will be described. Address management means 4
When the device information DI is acquired from the device management means 41, the device 6 searches the address table AT for the same device information DI. That is, when the device management unit 41 sends the device information DI to the address management unit 46, it is limited to when the new device 20 is connected to the computer. On the other hand, once computer 1
Device information D for the device 20 connected to
The address table AT in which I or the virtual device address HDA is linked is created. Therefore, when the address management means 46 receives the device information DI, it searches the address table AT to determine whether the device 20 is newly connected or reconnected. There is.

When the same device information DI exists as a result of the search, the address management means 46 updates the device address ADDR linked to the device information DI to the device address ADDR newly assigned by the address setting means 42. The created address table AT is created. On the other hand, when the same device information DI does not exist, the address management means 46 causes the virtual address setting means 43.
To request the allocation of the virtual device address HDA.
Then, the address management means 46 creates a new address table AT in which the device address ADDR of the newly connected device 20, the virtual device address HDA and the device information DI are linked.

The address management means 46 has a function of sending the virtual device address HDA to the application monitoring means 44 in response to a request from the application monitoring means 44. Then, the application monitoring means 44
Notifies the application 50 virtual device address HDA so that the application 50 can specify the device 20 by the virtual device address HDA.

Further, the address management means 46 responds to the request from the address conversion means 45 to generate the virtual device address
It has a function of searching the device address ADDR corresponding to DA and sending it to the address conversion means 45. Then, the address conversion unit 45 converts the virtual device address HDA in the data D1 into the device address ADDR and sends it to the device management unit 41.

As described above, the address management means 46 allocates the virtual device address HDA when the new device 20 is searched. However, when the application monitoring means 44 makes a request, the virtual device address HDA is allocated. The virtual device address HDA may be requested to the address setting means 43. At this time, until there is a request from the application monitoring means 44, the address table AT in which only the device address ADDR and the device information DI are linked is created.

6 to 8 are flowcharts showing a preferred embodiment of the data control method of the present invention, and the data control method will be described with reference to FIGS. 1 to 8. 6 is a device recognition process, FIG. 7 is a data transfer process to the device, and FIG. 8 is a flowchart showing the process of disconnecting and reconnecting the device 20.

First, the recognition process of the device 20 will be described with reference to FIG. If the device 20 is not connected, the device
Is recognized as not existing. On the other hand, when the device 20 is connected, the device management unit 41 recognizes the device connection by the change in the current of the USB port (step ST1).

Then, in the device management means 41,
Enumeration is executed. Specifically, Control transfer is performed from the device management means 41 to the device 20. By this Control transfer, the device 20 having the default address is transferred to the device management means 4
Recognized by 1. Thereafter, the device management unit 41 requests the address setting unit 42 to request the device address ADDR to be assigned to the device 20.

Then, in the address setting means 42,
The device address ADDR of the connected device 20 is set with reference to the address table AT so as not to conflict with other devices 20, and the device management means 41
Sent to. The set device address ADDR is
It is sent from the address setting means 42 to the address management means 46. After that, the device address ADDR is sent to the device 20 side by the token packet, and the device 2
The device address ADDR is stored in the 0 buffer (step ST2).

Next, the device management unit 41 acquires the configuration information such as the device descriptor and the configuration descriptor from the device 20. As a result, the functions of the device 20 can be used on the computer 1. In reading the configuration information, the device information DI described in the device descriptor is read (step ST3). Then, the device management means 41 causes the “In
f "file to compare with the driver list.
If the same device information DI exists in the Inf file, the device driver is read in the computer 1. This brings the device into a usable state on the computer 1. On the other hand, if the recognized device 20 is not in the driver list in the computer 1, the device driver is installed on the computer 1.

Then, the read device information DI is
It is sent from the device management means 41 to the address management means 46. After that, the virtual device address HDA is assigned by the virtual address setting means 43 so as not to conflict with other devices 20, and is sent to the device management means 41 (step ST4). Then the device address A
An address table AT in which the DDR, the virtual device address HDA and the device information DI are linked is created by the device management means 41 (step ST5).

Next, with reference to FIGS. 3 and 7, the process of starting the application 50 and transferring data from the application 50 to the device 20 will be described. First,
The application 50 is activated on the computer 1 by a user operation or the like (step ST10). When the application 50 is activated, a request for the virtual device address HDA is sent from the application monitoring means 44 to the address management means 46 (step ST11).
Then, the address management means 46 searches the address table AT for the device address ADDR of the corresponding device 20. After that, the virtual device address HDA linked with the device address ADDR is acquired by the address management means 46 and sent to the application 50 via the application monitoring means 44. Then, the application 50 sends the device 20
Is specified by the virtual device address HDA.

Next, when the data D1 is transferred from the application 50 to the device 20, the data D1 is transferred from the application 50 to the address conversion means 45 via the application monitoring means 44 (step S).
T12). Then, the address conversion means 45 recognizes the virtual device address HDA included in the data D1 (step ST13). Then, the request for the device address ADDR corresponding to the virtual device address HDA attached to the data D1 is sent from the address conversion means 45 to the address management means 46. After that, the address conversion means 45 causes the virtual device address H of the data D1.
DA is converted into the device address ADDR acquired from the address management means 46. Then, the converted data D10
Is generated and sent from the address conversion means 45 to the device management means 41.

Then, the conversion data D10 is packet-transmitted from the device management means 41 to the device 20, and the conversion data D10 is transferred to the device 20 to which the device address ADDR attached to the conversion data D10 is assigned (step ST14). ). Accordingly, even when the application 50 specifies the device 20 using the virtual device address HDA, it is possible to access the device 20 specified by the application 50.

Next, a case where the device 20 is disconnected or turned off and then reconnected will be described with reference to FIG. In FIG. 8, the application 5
Note the case where there was a reconnection when 0 was up.

First, when the application is running, the connection state of the device 20 is always the device management means 4
1 is monitored (steps ST20, ST2)
1). The device management means 41 also monitors whether or not the device 20 has been disconnected (step S).
T22). Here, when the device 20 is disconnected from the computer 1, the device management unit 41 recognizes the disconnection of the device 20. When the conversion data D10 is transferred from the application 50 to the device 20 in this state (step ST23), the device management unit 4
1 outputs information indicating an error to the system of the computer 1 (step ST24).

On the other hand, when the device 20 disconnected from the application 50 without data transfer to the device 20 is reconnected (step ST26), the device 20 is recognized and a new device address ADD is added.
Rn is assigned (see steps ST1 to ST3 in FIG. 6). Then, the assigned device address ADDRn is sent from the device management means 41 to the address management means 46, and the device information D
In is the address setting means 42 to the address management means 46.
Sent to.

Then, in the address management means 46,
The same device information D as the sent new device information DIn
It is searched whether or not I is in the address table AT (step ST27). If the same device information DI as the new device information DIn does not exist, that is, if the new device 20 is connected, a new address table AT is created by the address management means 46 as in step ST5 of FIG. 6 (step ST29). ).

On the other hand, when there is the same device information DI as the new device information DIn, only the device address ADDR in the address table AT is rewritten, and the new device address ADDRn, the virtual device address HDA and the device information DI are relinked. The address table AT is updated and stored (step ST28).

Then, when the application 50 transfers data to the device 20, the virtual device address HDA included in the data is converted into the newly assigned device address ADDRn and sent to the device 20. Then, the data D1 sent from the application 50 is transferred to the device 20.

According to the above embodiment, the virtual device address HDA for the device 20 does not change even if the device address ADDR changes due to the reconnection of the device 20. Therefore, application 5
When 0 accesses the reconnected device 20, the time for searching the device 20 becomes unnecessary, or it becomes unnecessary to restart the application 50 due to the occurrence of an access error. Therefore, the user interface can be improved.

The embodiment of the present invention is not limited to the above embodiment. For example, in the above embodiment, when a plurality of applications 50 are installed, the device 2 is set by the virtual device address HDA.
Whether to specify 0 or the device address ADDR may be selectable for each application 50. Specifically, the application monitoring means 44
Has an application list that uses the virtual device address HDA, and only when the corresponding application 50 is activated, the virtual device address HDA
May be used.

Even if the application 50 is not activated, the device management means 41 may always monitor the connection state of the device 20 while the computer 1 is activated. This allows application 5
Even when the device 20 is disconnected / reconnected when 0 is not started, the address table AT can be updated at any time.

Further, in the above-mentioned embodiment, the case of the USB interface is illustrated as the hot-pluggable interface. For example, IEEE1
It can be applied to a hot-swap interface as well as a USB interface such as a 394 interface.

Further, the device control apparatus 40 of FIG. 3 causes the computer to read the device control program,
It may be provided as a specific means in which a computer and a device control program cooperate. This device control program is a device control program for controlling a device connected to a computer by using a hot-swap interface, recognizes that the device is connected to the computer, and outputs device information from the device. When the device management unit to acquire and the device is recognized by the device management unit,
Address setting means for allocating a device address for identifying the device to the device, and a virtual device address allocating virtual device address for identifying the device when the application running on the computer uses the device Address setting means, the virtual device address assigned by the virtual address setting means, the device address assigned by the address setting means,
An address management unit that creates and stores an address table linked with the device information acquired by the device management unit, and, when the application accesses the device, sends the address table from the application using the address table. Address conversion means for converting the virtual device address included in the data to the device address linked to the virtual device address and sending the device address to the device, wherein the address management means disconnects the device from the computer. When the device is reconnected again, the new device information newly acquired from the device is used to search the address table for the same device information as the newly allocated new device information, and the address table is searched. Within the new device If there is a dress same device information and, to update the device addresses linked to the device information to the new device address may be a device control program causing a computer to function.

[Brief description of drawings]

FIG. 1 is a diagram showing a state in which devices are connected to a computer by using a hot-pluggable interface.

FIG. 2 is a block diagram showing a hierarchical structure of the computer and the device of FIG.

FIG. 3 is a block diagram showing a preferred embodiment of the device control apparatus of the present invention.

FIG. 4 is a diagram showing a data structure of a token packet transferred from the device management means of FIG. 3 to a device.

5 is a diagram showing a data structure of an address table created by the address management means of FIG.

FIG. 6 is a flowchart showing a preferred embodiment of the device control method of the present invention.

FIG. 7 is a flowchart showing a preferred embodiment of the device control method of the present invention.

FIG. 8 is a flowchart showing a preferred embodiment of the device control method of the present invention.

[Explanation of symbols]

1 computer 10 cables 20 devices 40 device controller 41 Device management means 42 Address setting means 43 Virtual address setting means 44 Application monitoring means 45 Address conversion means 46 Address management means 50 applications ADDR device address ADDRn new device address AT address table D1 data D10 conversion data DI device information DIn new device information DIn new device information HDA virtual device address

Claims (3)

[Claims] 1. A device control method for controlling a device connected to a computer by using a hot-swappable interface, wherein device information is acquired from the device when the device is connected to the computer, Assigning a device address for identifying the device to the device, assigning a virtual device address for identifying the device to the device when an application running on the computer uses the device, Creating an address table in which the virtual device address assigned to the device, the device address, and the device information are linked; and when the application accesses the device, the address table is created. And converting the virtual device address included in the data sent from the application into the device address linked to the virtual device address and sending the device address to the device, the device disconnecting from the computer. And reconnecting again, using the new device information newly acquired from the device, searching the same device information from the address table; and the new device address in the address table. If the same device information is present, updating the device address linked to the device information to the new device address, the device control method. 2. A device control apparatus for controlling a device connected to a computer using a hot-swappable interface, recognizing that the device is connected to the computer, and acquiring device information from the device. Device management means for controlling the device, an address setting means for allocating a device address for identifying the device to the device when the device is recognized by the device management means, and an application running on the computer A virtual address setting means for assigning a virtual device address for the application to identify the device when used, the virtual device address assigned by the virtual address setting means, and the virtual device address assigned by the address setting means. Address management means for creating and storing an address table in which the device address and the device information acquired by the device management means are linked to each other; and when the application accesses the device, the address table is used. An address conversion unit that converts the virtual device address included in the data sent from the application into the device address linked to the virtual device address and sends the device address to the device, When the device is disconnected from the computer and reconnected, the new device information newly obtained from the device is used to search the address table for the same device information as the newly allocated new device information. The address If the device information that is the same as the new device address is present in the record, the virtual device address remains the same and the device address linked to the device information is updated to the new device address. Control device. 3. The device control apparatus according to claim 2, wherein the address table is stored in a storage device connected to the computer.