JP2000284982A - Access controller and computer readable storage medium storing program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently realize the multiplication of access from a certain device to an outside device. SOLUTION: When a prescribed device 17 is connected through plural transmission media with an outside device 2, this controller 18 controls access from the prescribed device 17 to the outside device 2. This controller 18 operates access from a communication interface control program 8 between the prescribed device 17 and the outside device 2 by a first access path 22A using a transmission media 3a. Also, when the access by the first access path 22A is impossible, this controller 18 operates access from the communication interface control program 8 by a second access path 22B using a transmission medium 3b other than the transmission medium 3a used by the first access path 22A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an access control device for controlling access when a predetermined device and an external device are connected and multiplexed by a plurality of transmission media, and a computer readable program storing a program. It relates to a storage medium.

[0002]

2. Description of the Related Art Computers using a disk array system (RAID [Redundant Arrays of Inexpensive Dis
k] computer), there is a case where the computer and the disk array device are duplicated in order to improve the reliability between the host computer and the disk array device.

FIG. 2 is a block diagram showing a first conventional example in which a computer and a disk array device are duplicated.

In the first configuration example, two SCSI cables 3 are connected between the computer 1 and the disk array device 2.
a, 3b.

The computer 1 mainly includes a user application 4 and an operating system (hereinafter referred to as an “OS”).
5) and two SCSI cards 6a and 6b.

[0006] The user application 4 provided in the computer 1 is an application program, and has a function of switching an access path to the disk array device 2 in order to realize a redundant access.

In the case of a normal user application, the devices connected to the computer 1 are recognized as individual devices. However, in the user application 4, the devices specially connected by the SCSI cards 6a and 6b are used. Is a single disk array device 2.

[0008] The OS 5 mainly includes a file system 7 and an S
It includes a CSI disk driver 8 and a SCSI adapter driver 9.

The file system 7 is an OS standard program that manages the arrangement of files using, for example, a tree structure.

The SCSI disk driver 8 is a SCSI disk driver.
This is an OS standard program for controlling a communication interface by the OS. This SCSI disk driver 8
This is a driver exclusively for the CSI disk, and has a function for performing a disk-specific access such as, for example, Seek of the disk.

The SCSI adapter driver 9 is a driver for a general-purpose SCSI device, and includes a SCSI card 6a,
The OS standard program controls data transfer between the disk array device 6b and the disk array device 2. Note that this SCSI
The adapter driver 9 has a function of detecting a hardware failure and notifying the access source when a failure occurs in the access destination controller during access.

On the other hand, the disk array device 2 includes a disk array 10 and two controllers 11a and 11b.

The disk array 10 stores the decomposed data on a plurality of disks so that the data can be read or written in parallel.

The controllers 11a and 11b control reading or writing to the disk array 10.

The SCSI cables 3a and 3b connect the SCSI cards 6a and 6b of the computer 1 and the controllers 11a and 11b of the disk array device 2 in a transmittable state.

As described above, in the case where a controller dual configuration in which the access path between the computer 1 and the disk array device 2 is duplicated is realized, the user application 4 executes processing 7 by the file system 7, for example.
a, processing 8a by the SCSI disk driver 8, SC
Through processing 9a by the SI adapter driver 9, the SCS
I card 6a, SCSI cable 3a, controller 1
The disk array 10 is accessed via 1a (this access path is referred to as "first path 12A").

Here, it is assumed that a failure of, for example, the controller 11a occurs during access by the first route 12A.

Then, the failure of the controller 11a is detected by the processing 9a of the SCSI adapter driver 9, and the hardware failure is detected by the processing 8a by the SCSI disk driver 8 and the processing 7a by the file system 7.
Is notified to the user application 4 via.

When a hardware failure is detected in the user application 4, the access path is switched by the switching function, and the processing by the file system 7 is executed.
b, processing 8b by the SCSI disk driver 8, SC
Through processing 9b by the SI adapter driver 9, the SCS
I card 6b, SCSI cable 3b, controller 1
The disk array 10 is accessed via 1b (this access path is referred to as "second path 12B").

There is also a case where the duplication between the computer and the disk array device is realized by a method different from the first conventional example.

FIG. 3 is a block diagram showing a second conventional example in the case where the computer and the disk array device are duplicated, and the same parts as those in FIG. 2 are denoted by the same reference numerals.

The computer 13 in FIG. 3 does not include a switching function in place of the above-described user application 4 of the computer 1 and does not recognize that the connected device is a single device. And a disk array device dedicated driver 1
The difference is that 5 is added.

The user application 14 of the computer 13
Has a process to be provided to the user, but does not have a switching function like the user application 4 described above, and does not recognize that the device connected to the computer 13 is a single device. It is a normal application.

The disk array device dedicated driver 15 is
As with the OS standard SCSI disk driver 8, the SC
It has a function of controlling the communication interface by the SI.

The disk array device dedicated driver 15 recognizes an access route to the disk array device 2 and has a function of switching to a different route when an access error occurs.

In the second conventional example realized with such a configuration, the disk array device dedicated driver 15 is accessed from the user application 14 through the processing by the file system 7.

In the disk array device dedicated driver 15, according to the access from the file system 7,
The control of the communication interface by the CSI is executed, and a process 9a is requested to the SCSI adapter driver 9 to realize an accessible path.

Thus, the SCSI adapter driver 9
Card 6a, SCSI 9a
The disk array 10 is accessed via the cable 3a and the controller 11a (this access path is referred to as a "first path 16A").

Here, it is assumed that an abnormality such as a hardware failure of the controller 11a is detected by the processing 9a of the SCSI adapter driver 9, and the fact is notified to the disk array device dedicated driver 15.

Then, by the switching function of the disk array device dedicated driver 15, a process 9b is requested to the SCSI adapter driver 9 to realize an accessible path.

Thus, the SCSI adapter driver 9
Card 6b, SCSI 9b
The disk array 10 is accessed via the cable 3b and the controller 11b (this access path is referred to as a "first path 16B").

[0032]

As described above, in the related art, the computer and the disk array device are duplicated in order to ensure high access reliability. A single disk array device is recognized as a separate disk array device.

Therefore, it is necessary for the computer to recognize that the disk array device is a single device and is a duplicate device.

In the above-described first conventional example, the user application recognizes that the connected disk array device is a single device, and switches the path when the user application accesses.

In the second conventional example, the dedicated driver for the disk array device is recognized as a single disk array device, and the access path is switched by the dedicated driver for the disk array device.

However, when duplication between a computer and a disk array device is realized by each of the conventional methods, the following problems occur.

First, in the first conventional example, it is necessary to make the user application aware of the duplication, and to include the function of switching the access path, so that a normal user application cannot be applied as it is.

For this reason, it is necessary to recognize various paths and add a switching function to various user applications provided in a computer using the disk array device, and it takes time and effort to remodel the user applications.

On the other hand, in the second conventional example, it is necessary to develop a disk driver dedicated to the disk array device. This dedicated driver for the disk array device is developed by modifying an existing SCSI disk driver included in the OS. It is generally done.

However, if the OS itself is not a product of its own, it is difficult to modify an existing SCSI disk driver.

In order to independently develop a dedicated driver for this disk array device, it is necessary to have knowledge of a SCSI disk driver. This SCSI disk driver has an interface with a file system included in the OS. Requires knowledge of the file system.

Therefore, the development amount of the driver dedicated to the disk array device increases, and this development work requires labor and time.

The present invention has been made in view of the above circumstances, and has an access control device for realizing multiplexed access between a predetermined device and an external device without modifying a user application or an OS. And a computer-readable storage medium storing a program and a program.

[0044]

The gist of the present invention is to control access to an external device executed by a communication interface driver by selecting an accessible communication medium from a plurality of communication media connected to the external device. The point is to realize.

Hereinafter, specific means taken for realizing the present invention will be described.

A first aspect of the present invention is a device for controlling access from a predetermined device to an external device when the predetermined device and the external device are connected by a plurality of transmission media. Means for realizing access from a control program relating to a communication interface between the communication device and an external device through a first access path using any one of a plurality of transmission media, and making access via the first access path impossible In this case, the access from the control program relating to the communication interface is realized by the second access path using another transmission medium other than the transmission medium used by the first access path among the plurality of transmission media. And an access control device comprising:

In the first aspect, the access by the existing communication interface control program is realized by a normal path among a plurality of access paths to the external device.

Therefore, there is no need to modify existing communication interface control programs or user applications to realize multiplex communication with a single external device.

Therefore, the reliability of access can be easily improved. Further, the labor and time required for remodeling the existing communication interface control program and user application can be eliminated.

Further, since the existing communication interface control program and existing user application can be used as they are, it is possible to prevent the occurrence of a bug due to the program development and to maintain high reliability.

Further, when the first aspect of the present invention is applied, for a user application or a user, access to a multiplex-connected external device can be realized by the same method as ordinary access.

Therefore, operability of the user can be maintained.

According to a second aspect of the present invention, there is provided the access control apparatus according to the first aspect of the invention, further comprising a notifying means for notifying that the first access path has been switched to the second access path. .

According to the second aspect of the present invention, the user can be notified that the access route has been switched, so that the user's management work can be supported.

Further, by notifying the user which access route is accessible and which access route is inaccessible, the user can repair the portion related to the inaccessible route and actively recover from the failure. Can be planned.

A third invention is a device for controlling access from a predetermined device to an external device when a predetermined device and an external device are connected by a plurality of transmission media. Means for selecting any one of a plurality of access paths that can access an external device using the access path, and an access path selected by the path selection means, whereby a predetermined device and an external device An access control device comprising: an access realizing unit that realizes an access from a control program related to a communication interface.

In the third invention, similarly to the first invention, the access from the communication interface control program to the external device is realized by an accessible path among a plurality of access paths. The operation and effect of the present invention can be obtained.

A fourth aspect of the present invention is the access control apparatus according to the third aspect of the present invention, further comprising a notifying means for notifying the selection status of the route selecting means.

When the selection status of the access route is notified as in the fourth invention, the user can be notified that the access route has been switched, as in the second invention. Therefore, the same function and effect as the second invention can be obtained.

A fifth invention is the access control device according to the first to fourth inventions, wherein an access from a communication interface control program included in an operating system provided in a predetermined device is controlled by the operating system. Is an access control device realized by a data transfer control program to an external device included in.

When the fifth aspect of the invention is applied, multiplex access to an external device is realized by using the existing communication interface control program and data transfer control program included in the OS as they are.

Accordingly, the development effort required for realizing the multiplexing of transmission media for a single external device can be reduced, and bugs that occur with this development can be prevented. Control program for controlling access from a predetermined device to an external device when the device and the external device are connected by a plurality of transmission media, and a control program related to a communication interface between the predetermined device and the external device And a function of realizing an access from a plurality of transmission media when a first access route using any one of the plurality of transmission media is used. The communication interface is controlled by a second access path using another transmission medium other than the transmission medium used by the first access path. A computer-readable storage medium that stores a program that realizes a function of realizing access from a control program.

A seventh invention is a computer-readable storage medium storing the program described in the sixth invention, wherein the program is provided with a notification function for notifying that the first access path has been switched to the second access path. It is a readable storage medium.

An eighth invention is a program for controlling access from a predetermined device to an external device when a predetermined device and an external device are connected by a plurality of transmission media, and the program is provided for each transmission medium. Between a predetermined device and an external device by using a route selection function for selecting any one of a plurality of access routes that utilize an access to the external device, and an access route selected by the route selection function. A computer-readable storage medium storing a program for realizing an access realizing function for realizing access from a control program related to a communication interface.

A ninth invention is a computer-readable storage medium storing the program described in the eighth invention, the program having a notification function for notifying the selection status of the route selection function.

A tenth invention is the program described in the sixth to ninth inventions, wherein an access from a communication interface control program included in an operating system provided in a predetermined device is performed by the operating system. Is a computer-readable storage medium storing a program realized by a data transfer control program to an external device included in the program.

The sixth to tenth aspects of the present invention are computer-readable storage media storing a program for realizing the functions of the access control device described in the first to fifth aspects by a computer.

By using a storage medium storing such a program, the above-described functions can be easily added to a device, a computer, and a computer system that do not have the above-mentioned functions.

[0069]

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

(First Embodiment) In this embodiment, when a computer and an external device are connected by two SCSI cables, multiplexed access is realized without modifying a user application or an OS. The following describes an access control device that performs this operation.

FIG. 1 is a block diagram showing the configuration of the access control apparatus according to the present embodiment. The same parts as those shown in FIG. 2 and FIG. It will be omitted or briefly described, and only different portions will be described in detail here.

The computer 17 is provided with an existing user application 14 which does not recognize an access route relating to duplication and does not have a switching function, an existing OS 5, and two SCSI cards 6a and 6b. The two SCSI cards 6a and 6b and the disk array device 2
The two controllers 11a and 11b are connected by SCSI cables 3a and 3b. Further, the computer 17 includes an access control device 18 according to the present embodiment.
Is provided.

Access control device 18 according to the present embodiment
OS5 standard SCSI disk driver 8 and OS5
It operates by being incorporated between the standard SCSI adapter drivers 9 and mainly includes a path selection unit 19, an access realization unit 20, and a notification unit 21.

The path selecting section 19 is provided for each SCSI cable 3
a, 3b, the access paths 22A, 22B to the disk array device 2 are recognized.
Table 19 indicates whether access is possible for each of 2A and 22B.
a. Then, when one of the access paths becomes inaccessible, the access instruction unit 20 is notified of a switching command indicating that the access path is switched to the other accessible access path.

The method of determining whether or not the path can be accessed in the path selecting section 19 is, for example, when access to this path is received when a hardware failure notification is received from the SCSI adapter driver 9 during access through one of the access paths. A method of disabling is available. Also, when read data is not obtained after a lapse of a predetermined time from the start of access in read access, or when a predetermined time has lapsed after the start of access in a write access, a notification of normal end of writing is obtained. A method of determining that access is not possible when access is not possible is also available. Further, it is also possible to use a method of determining that access is not possible when a read error notification is received as a response to a read access or when a write error notification is received as a response to a write access.

The access realizing section 20 recognizes an accessible access path based on the switching command received from the path selecting section 19, and when the access from the SCSI disk driver 8 is an access to the disk array device 2, the SCSI adapter The driver 9 is requested to perform processing for realizing access by the recognized route.

That is, this access realizing unit 20
In order to realize the access from the CSI disk driver 8 by one of the access paths 22A and 22B, a request is made to the SCSI adapter driver 9 for processing.
When a path switching command is issued from the path selection unit 19, a new process is requested to the SCSI adapter driver 9 in order to realize an access path to the disk array 10 by another access path.

Further, the access realizing unit does not notify the SCSI disk driver 8 of a response regarding the occurrence of an abnormality or a failure as long as the access is realized by any of the routes.

The notifying section 21 notifies the user of the contents of the table 19a of the path selecting section 19 and the fact that the access path has been switched. For example, the contents of the table 19a are displayed on a display, and when an inaccessible route occurs, the occurrence of an abnormality is output on the screen and in audio.

The notification unit 21 has a function of accepting from the user that the access route has been restored, and updating the contents of the table 19a relating to the restored access route.

The access control processing when the access control device 18 having the above configuration is provided will be described below.

When the user application 14 accesses the disk array 10 such as writing / reading, the access control device 18 is accessed via the access path 23 via the processing by the file system 7 and the processing by the SCSI disk driver 8. You.

In the path selection section 19 of the access control device 18, the SCSI
Data transfer control processing 9a for card 6a, SCSI
Card 6a, SCSI cable 3a, controller 11
The access path 22A for accessing the disk array 10 via a is managed. The data transfer control processing 9b for the SCSI card 6b by the SCSI adapter driver 9 and the disk array 1 via the SCSI card 6b, the SCSI cable 3b, and the controller 11b.
The access path 22B for accessing 0 is also managed.

In a normal case, a switching command for selecting the access path 22A is issued from the path selecting section 19 to the access realizing section 2.
0 has been notified.

When the access control device 18 is accessed from the SCSI disk driver 8, the access from the SCSI disk driver 8 is transferred to the access path 22A.
In order to realize the above, the data transfer control by the SCSI card 6a is requested from the access realizing unit 20 to the SCSI adapter driver 9.

Thus, the SCSI disk driver 8
Access to the access control device 18 from the
The processing is performed on the disk array 10 via the processing 9a by the SI adapter driver 9, the SCSI card 6a, the SCSI cable 3a, and the controller 11a.

Here, as a response to the access, the path selector 19 of the access controller 18 receives a write error notification or a read error notification from the disk array device 2, or receives a path error notification from the SCSI adapter driver 9.
Is assumed to have received the information of the hardware failure notification, or that the route selection unit 19 has not received a response to the access even after a predetermined time has elapsed.

Then, the route selecting unit 19 recognizes that the access route 22A is inaccessible, and notifies the access realizing unit 20 of a switching command to the access route 22B recognized as accessible. Further, the user is notified that the access route is switched from the route selection unit 19 via the notification unit 21.

However, the access control device 18 does not notify the inaccessible notification to the SCSI disk driver 8, the file system 7, and the user application 14.
The file system 7 and the user application 14 continue the same processing as before the access path switching.

In accordance with the switching command from the path selecting unit 19, the access realizing unit 20 sends the SCSI adapter driver 9 the SC adapter driver 9 in order to realize the access from the SCSI disk driver 9 by the access path 22B.
A data transfer control process 9b by the SI card 6b is required.

As a result, the SCSI disk driver 8
Access to the access control device 18 from the
The processing 9b by the SI adapter driver 9 is performed on the disk array 10 via the SCSI card 6b, the SCSI cable 3b, and the controller 11b.

The user investigates the access route 22A,
When the abnormality has been recovered, the fact is notified to the route selection unit 119 via the notification unit 21, and the contents of the table 19a are updated when the access route 22A is accessible.

As described above, the access control device 18 according to the present embodiment is an OS standard driver S
It is incorporated between the CSI disk driver 8 and the SCSI adapter driver 9 and does not require modification of the OS standard driver.

Therefore, existing software resources can be utilized, multiplexing can be easily introduced, and reliability can be improved.

Further, development effort, development time, and the like for realizing multiplexing by utilizing existing software resources are described.
Development costs can be reduced. Furthermore, bugs that occur during development can be reduced, and the reliability of the program can be maintained.

Further, the access control device 18 according to the present embodiment manages an access path from after the SCSI disk driver 8 to the disk array 10 to provide a normal access path.

Therefore, the user application 14
However, the devices connected to the SCSI card 6a and the SCSI card 6b do not need to be recognized as one device. For this reason, the user application 14 can access the disk array device 2 as in the normal case, and there is no need to change the user's operation.

Therefore, it is not necessary to modify the user application 14, and the operability of the user can be maintained.

Therefore, it is possible to provide high-quality multiple access more easily than by adding a switching function to a user application or developing a dedicated driver for a disk array device and performing multiple access.

Although the present embodiment shows a state in which the access control device 18 is built in the computer 17, it may be used externally. Also, the computer 17 may be mounted on an expansion card or an expansion board.

Further, in the present embodiment, the case where the accessing side is the computer 17 and the accessed side is the disk array prime value is described as an example, but the present invention is not limited to this.

For example, the accessing side is not limited to a computer, and various devices that access other devices using a predetermined communication interface such as a computer system and a communication device according to the present embodiment are also applicable. An access control device can be applied.

Also, the side to be accessed is not limited to the disk array device, but may be a magnetic disk device, an optical disk device,
The access control device according to the present embodiment is applicable to various peripheral devices such as a magneto-optical disk device, a computer, and various devices accessed from other devices using a predetermined communication interface such as a computer system. it can.

Further, in the present embodiment, the case where the communication interface is SCSI is described, but the access control device can be similarly applied to other communication interfaces such as Ultra SCSI and Fiber Channel. .

The configuration of the access control apparatus according to the present embodiment is not limited to the case described above, and can be combined, disassembled, or variously modified as long as the same functions and actions can be realized.

Further, in the present embodiment, the case where the accessing device and the accessed device are duplicated has been described. The same can be applied.

Each function and each element of the access control apparatus according to the present embodiment are, for example, a magnetic disk (floppy (registered trademark) disk, hard disk or the like), an optical disk (CD -ROM, DVD, etc.), and can be applied by writing to a storage medium such as a semiconductor memory, or transmitted to a communication medium and applied to various devices. A computer that realizes each of the above functions and elements reads the program stored in the storage medium, and executes the above-described processing by controlling the operation of the program.

For example, if a program for realizing the same functions as those of the components 19 to 21 of the above access control device is stored in a storage medium, and this program is installed in the accessing device, the present embodiment The same operation as that of the access control device described in (1) can be realized.

[0109]

As described above, in the present invention,
When a predetermined device and an external device are connected by a plurality of transmission media, by switching access from the control program related to the existing communication interface, multiplexed access can be performed without modifying the control program related to the existing communication interface. Has been realized.

As a result, the access can be realized by effectively utilizing the existing program, so that the amount of program development accompanying the introduction of multiplexing is greatly reduced, and the occurrence of bugs accompanying the introduction of multiplexing is prevented. Can be.

Further, since the external device can be accessed by the user and the user application in the same way as a normal device, the operability of the user is maintained and the user application does not need to be remodeled.

Therefore, multiplexing of access from a certain device to an external device can be efficiently realized, and a high-quality multiplexing service can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an access control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a first conventional example when a computer and a disk array device are duplicated.

FIG. 3 is a block diagram showing a second conventional example when a computer and a disk array device are duplicated.

[Explanation of symbols]

 1, 13, 17 Computer 2 Disk array device 3a, 3b SCSI cable 4, 14 User application 5 Operating system 6a, 6b SCSI card 7 File system 8 SCSI disk driver 9 SCSI adapter driver 10 ... Disk array 11a, 11b Controller 15 Disk array device dedicated driver 18 Access control device 19 Route selection unit 20 Access realizing unit 21 Notification unit

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G06F 13/14 310 G06F 13/14 310E F term (reference) 5B014 EA05 EB04 FA04 5B018 GA06 HA02 KA01 MA14 MA34 PA03 5B034 BB01 CC05 5B065 BA01 CA05 CA13 CA30 CE06 CE22 CH13 EA12 5B083 AA08 BB03 CC04 CD11 EE08

Claims (10)

[Claims] 1. An apparatus for controlling access from a predetermined device to the external device when the predetermined device and an external device are connected by a plurality of transmission media, the device comprising: Means for realizing access from a control program relating to a communication interface with the external device through a first access path using any one of the plurality of transmission media; and access through the first access path. When it becomes impossible, from the control program related to the communication interface, a second access path using another transmission medium other than the transmission medium used for the first access path among the plurality of transmission media is used. Means for realizing the above access. 2. The access control apparatus according to claim 1, further comprising a notification unit for notifying that the first access path has been switched to the second access path. apparatus. 3. A device for controlling access from a predetermined device to the external device when a predetermined device and an external device are connected by a plurality of transmission media, wherein each of the transmission media is A path selection unit that selects any one of the plurality of access paths that can be used to access the external device; and the predetermined device and the external device, based on the access path selected by the path selection unit. Access control means for realizing an access from a control program relating to a communication interface between the access control device and the access control device. 4. The access control device according to claim 3, further comprising a notification unit for notifying a selection status of the route selection unit. 5. The access control device according to claim 1, wherein an access from a communication interface control program included in an operating system provided in the predetermined device is performed. An access control device realized by a program for controlling data transfer to the external device included in the operating system. 6. A program for controlling access from a predetermined device to the external device when the predetermined device and the external device are connected by a plurality of transmission media, the program comprising: A function of realizing access from a control program relating to a communication interface with the external device through a first access path using any of the plurality of transmission media; and an access through the first access path. When it becomes impossible, from the control program related to the communication interface, a second access path using another transmission medium other than the transmission medium used for the first access path among the plurality of transmission media is used. -Readable storage medium storing a program for realizing the function of realizing the access to the computer 7. The computer readable storage according to claim 6, wherein a program having a notification function for notifying that the first access path has been switched to the second access path is added. Medium. 8. A program for controlling access from a predetermined device to the external device when the predetermined device and the external device are connected by a plurality of transmission media, the program comprising: A path selection function for selecting any of the plurality of access paths that can be used to access the external device, and an access path selected by the path selection function, the predetermined device and the external device A computer-readable storage medium storing a program for realizing an access realizing function for realizing access from a control program relating to a communication interface between the two. 9. The computer-readable storage medium according to claim 8, wherein the program further includes a notification function for notifying a selection status of the route selection function. 10. The program according to claim 6, wherein an access from a communication interface control program included in an operating system provided in the predetermined device is performed by the program. A computer-readable storage medium storing a program realized by the program for controlling data transfer to an external device included in an operating system.