JP2001143162A - Merchandise sales data processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely attain the virus check of a floppy disk to be handled by its own device. SOLUTION: When an access request from an OS to an FD drive is issued, any access to the drive can be forcedly inhibited, and whether or not the FD mounted on the drive is infected by virus can be detected by driving a virus detecting driver while the access is forcedly inhibited. When it is detected that the FD is not infected by any virus, the forced inhibition of access to the FD drive is released so that access to the FD can be performed, and when it is detected that the FD is infected by virus, the forced inhibition of access to the FD drive is maintained, and warning that the FD is infected by virus can be outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floppy disk drive mounted on a floppy disk drive so that external information can be installed on the floppy disk drive. The product depends on the OS and utilizes the external information installed using the floppy disk. The present invention relates to a product sales data processing device formed so as to be able to execute sales data processing.

[0002]

2. Description of the Related Art For example, in an electronic cash register type product sales data processing apparatus, external information (for example, programs, setting data, sales data, etc.) can be installed from a floppy disk mounted on a floppy disk drive. Product sales data processing (product registration, accounting, etc.) using external information that depends on the OS and is installed using a floppy disk
It is formed to be executable.

[0003] Most of the programs and setting data that are external information are generally installed before the store is opened. However, sales data and some setting data may be installed during product sales data processing. Occurs.

Here, an application indirectly or through an OS (operating system)
When an access request to the floppy disk is issued directly from S, an interrupt signal is generated and the floppy disk drive is accessed via the head address for accessing the floppy disk drive set (stored) in a predetermined memory. The file stored in the floppy disk is read and written.

[0005]

By the way, the floppy disk mounted on the floppy disk drive is
Some items are delivered from outside (headquarters, other stores, etc.) as well as inside the own store. Thus, the chances of entry of virus-infected floppy disks are increasing.

However, in the actual operation of the store, the time of opening the store is approaching, and especially during the processing of the merchandise sales data, the technical expert checks all the delivered floppy disks for viruses using, for example, a dedicated machine. It is very difficult to do.

Therefore, if the floppy disk is accessed without knowing that it is infected with a virus, the merchandise sales data processing apparatus not only causes data processing malfunction or data destruction, but also causes a data communication network (for example, , LAN), a merchandise sales data processing system and a merchandise sales data processing system constructed by connecting these host machines may cause a system down. In this case, the store has to be closed.

An object of the present invention is to provide a merchandise sales data processing apparatus capable of reliably and automatically detecting a virus infection on a floppy disk handled in its own machine.

[0009]

According to the first aspect of the present invention, external information is formed so that external information can be installed from a floppy disk mounted on a floppy disk drive, and the external information depends on the OS and is installed using the floppy disk. In a product sales data processing device formed to be able to execute product sales data processing using
When an access request to the floppy disk drive is issued from the OS, access to the floppy disk drive can be forcibly prohibited. During this access prohibition, a virus detection driver is driven to drive the floppy disk attached to the floppy disk drive. It is formed to be able to detect whether the disk is infected with a virus,
If the detection result is not infected by a virus, the access prohibition of the floppy disk drive is released and the floppy disk mounted on the floppy disk drive is accessible and the detection result is infected by a virus. Is a merchandise sales data processing device formed so as to output an alarm indicating that a floppy disk is infected with a virus while the forced access prohibition of the floppy disk drive is maintained.

In this invention, for example, when the cashier mounts the floppy disk in the floppy disk drive and attempts to access the floppy disk by key operation, the OS issues an access request to the floppy disk drive in accordance with the attempt. Then, first, access to the floppy disk drive is forcibly prohibited,
Next, the virus detection driver is driven to automatically detect whether the floppy disk mounted on the floppy disk drive is infected with a virus.

If it is determined that the result of the detection is not infected with a virus, the forced prohibition of access to the floppy disk drive is released, and access to the floppy disk mounted on the floppy disk drive is permitted.
However, if the detection result indicates that the disk is infected with a virus, a warning that the floppy disk is infected with a virus is output while the access prohibition of the floppy disk drive is maintained (for example, display output is performed). , Voice output).

Therefore, it is possible to reliably detect the virus infection of the floppy disk handled in the own device. In addition, since the operation is automatically performed when accessing the floppy disk, it is easy to handle, and when a virus is infected, an alarm is output while the access is forcibly prohibited, so that the floppy disk is discarded. It is safe because you can.

According to a second aspect of the present invention, external information can be installed from a floppy disk mounted on a floppy disk drive, and the external information depends on the OS and uses the external information installed using the floppy disk. In a merchandise sales data processing apparatus formed so as to be able to execute merchandise sales data processing, a virus pattern storage means for storing a pattern of each virus which can infect the floppy disk, and a virus pattern storage means involved in the floppy disk drive And a virus detection driver capable of detecting whether or not the floppy disk mounted on the floppy disk drive is infected with a virus while referring to the above, and when the OS issues a request to access the floppy disk drive, Access compulsory prohibition control means for forcibly prohibiting access to a floppy disk drive, and a head address save control means for saving a floppy disk drive access head address stored in a predetermined memory to the save memory during the forced access prohibition Detection start address rewriting control means for rewriting the access start address stored in the predetermined memory to the detection start address of the virus detection driver after saving the access start address, and access compulsory prohibition control means after rewriting the detection start address And a virus detection driver driving control for driving a virus detection driver via a detection start address stored in a predetermined memory during temporary release of the forced access prohibition. And a rewrite control means for rewriting the detection start address stored in the predetermined memory to the original access head address when the detection result by the drive of the virus detection driver is not infected with a virus, and an address. Access forced prohibition release control means for releasing the forced access prohibition to the floppy disk drive by the access forced prohibition control means after rewriting, and the original access head address and the floppy disk stored in the predetermined memory after the cancellation of the access forced prohibition File access permission control means for permitting access to a file in the floppy disk mounted on the floppy disk drive via the drive, and a predetermined memory when a detection result by driving the virus detection driver is assumed to be infected with a virus. To A product sales data processing device provided with alarm output control means for outputting an alarm indicating that the floppy disk is infected with a virus while maintaining the stored detection start address and access forbidden state. is there.

In this invention, for example, when the cashier mounts the floppy disk in the floppy disk drive and attempts to access the floppy disk by key operation, the OS issues an access request to the floppy disk drive in accordance with the attempt. Then, the access compulsory prohibition control means forcibly prohibits access to the floppy disk drive.

During the forced access prohibition by the access forced prohibition control means, the head address save control means saves the head address for accessing the floppy disk drive stored in the predetermined memory in the save memory. Subsequently, the detection start address rewriting control means rewrites the access head address stored in the predetermined memory to the detection start address of the virus detection driver after saving the access head address. Then, the access compulsory prohibition temporary release control unit temporarily releases the access compulsory prohibition by the access compulsory prohibition control unit after rewriting the detection start address.

Here, the virus detection driver driving control means drives the virus detection driver via the detection start address stored in the predetermined memory while the access forced prohibition temporary release control means temporarily cancels the access prohibition. In other words, the virus detection driver refers to the virus pattern storage means in which the pattern of each virus involved in the floppy disk drive and capable of infecting the floppy disk is stored, and the floppy disk mounted on the floppy disk drive detects the virus. Automatically detect if infected.

If it is determined that the detection result by the driving of the virus detection driver is not infected with a virus, the rewrite control means rewrites the detection start address stored in the predetermined memory to the original access head address. do. Then, the access compulsory prohibition release control means releases the compulsory prohibition of access to the floppy disk drive by the access compulsory prohibition control means after rewriting the address. The file access permission control means permits access to the file in the floppy disk mounted on the floppy disk drive via the original access head address stored in the predetermined memory and the floppy disk drive after the forced access prohibition is released. . That is, it becomes accessible after confirming that it is not infected with a virus.

On the other hand, when it is assumed that the detection result by the drive of the virus detection driver is infected with the virus, the alarm output control means maintains the detection start address and the access forbidden state stored in the predetermined memory. Then, a warning is output to the effect that the floppy disk is infected with a virus.

Therefore, as in the case of the first aspect of the present invention, it is possible to reliably perform a virus check on a floppy disk handled in the own device. In addition, since it is automatically performed when accessing the floppy disk, it is easy to handle, and if a virus is infected, an alarm is output while the access is forcibly prohibited, so discard the floppy disk It is safe because you can do it. Furthermore, when there is a floppy disk access request, the access head address stored in the predetermined memory is rewritten to the detection start address of the virus detection driver, and if the virus check result indicates no infection, the original access head address is returned. Since it is configured to allow access to the floppy disk by returning to, the priority execution of virus detection can be reliably ensured.

Further, a third aspect of the present invention is a merchandise sales data processing apparatus wherein the OS is a single task system.

In this invention, even in the case of the single-task OS, the virus detection task of the floppy disk can be prioritized, so that the same operation and effect as those of the first and second inventions can be obtained. The present apparatus employing a relatively simple single-task OS can be constructed, and even in this case, reliable virus elimination can be guaranteed.

[0022]

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

The product sales data processing device (10) has an electronic cash register 10 as shown in FIGS. 1 and 2, and further has a virus pattern storage means 39P.
M, a virus detection driver (30, 39), a forced access prohibition control means (30, 39), a head address save control means (30, 39), a detection start address rewrite control means (30, 39), Access forced prohibition temporary release control means (30, 39), virus detection driver drive control means (30, 39), and rewrite control means (3
0, 39) and access forced prohibition release control means (30,
39) and file access permission control means (30, 3
9) and alarm output control means (30, 39) are provided.
When an access request to the floppy disk drive 40 is issued from S, the access to the drive 40 can be forcibly prohibited, and the virus detection driver (30, 39) is driven during this access prohibition to drive the drive 4.
0 is formed so as to detect whether or not the floppy disk FD mounted on the disk is infected with a virus, and when the result of the detection indicates that the virus is not infected, the forced access prohibition of the floppy disk drive 40 is released to release the floppy disk. If the detection result indicates that the floppy disk drive is accessible and the virus is infected, a warning that the floppy disk FD is infected with a virus can be output while maintaining the forced access prohibition of the floppy disk drive 40 maintained. Have been.

In FIG. 1, an electronic cash register 1
Reference numeral 0 denotes a control unit 30 including a CPU 31, a ROM 32, a RAM 33, a timer controller 34, and interfaces 35 and 36, and mounted on a motherboard, a floppy disk (FD) driver 40, a keyboard 4
1, an operator display (C) via the CRT board 37
RT) 42 and a personal computer 20 to which a hard disk drive (HDD) including a hard disk (HD) controller 38 and a hard disk (HD) 39 is connected.

The personal computer 20 has other data input means (card reader 46, scanner 4).
7) and output means [customer display unit (RIU) 43, receipt / journal (R / J) printer 45, automatic openable drawer 48, electronic buzzer 50] are connected, and an online board (interface) 49 and data It is connected to a higher-level device (not shown) via a communication network (LAN) 5 so that data communication is possible. The appearance is shown in FIG.

The OS executes a plurality of tasks or job programs related to merchandise sales data processing in a single task manner. During the virus infection detection operation described below,
Naturally, other job (task) programs are not executed. The present invention is applicable to a multitasking OS.

In the hard disk 39, an OS installed from the floppy disk FD or downloaded from a host machine through the data communication network 5 and various applications (APs) related to merchandise sales data processing are provided.
L), setting data and sales data are stored.
It is developed and executed on AM33.

Note that the OS installed via the floppy disk FD, various applications (APL) related to merchandise sales data processing, setting data, sales data, and the like are defined as external information.

For example, the electronic cash register 10
In the case where the external device (credit processing program and credit setting data) stored in the floppy disk FD (file) is installed, the credit processing using the card reader 46 can be performed.

That is, the electronic cash register 1
0 indicates that the external information can be installed from the floppy disk FD mounted on the floppy disk drive 40 and depends on the OS, and the product sales data processing can be executed using the external information installed using the floppy disk FD. Have been.

Here, the virus pattern storage means 39PM is a means for storing a pattern of each virus that can infect the floppy disk FD.
It is developed and used for AM33. The expanded virus pattern storage file is set to 33 PM.

The virus detection driver uses the floppy disk drive 40 [(specifically, the initial program loader (IP) of the floppy disk FD shown in FIG. 5).
L)] and the virus pattern storage file 33
Means for detecting whether or not the floppy disk FD mounted on the floppy disk drive 40 is infected with a virus while referring to the PM (39PM); and a hard disk (HD39) storing a virus detection program.
And the control unit 30 (31, 32, 33). The virus detection program is developed and used in the RAM 33.

This virus detection driver (30, 3
As shown in FIG. 3, 9) includes an initialization section, a virus detection section, an FD driver address save area 33SA, and a virus pattern data area [virus pattern storage file 33PM (39PM)]. The former two are code areas and the latter are data areas.

The virus detection driver (3
0, 39) and a hard disk (HD) 39 storing the following programs and the control unit 30 (31, 32,
33) may be formed, for example, from the program stored in the ROM 32 and the control unit 30.

Access forced prohibition control means (30, 39)
For example, when the application (APL) shown in FIG. 3 issues an access request to the floppy disk drive 40 required as the process proceeds, that is, when the OS issues an access request to the floppy disk drive 40 (FIG. 4), Access to the floppy disk drive 40 is forcibly prohibited. In this embodiment, the forced access is prohibited by forcibly stopping the generation of an interrupt signal (for example, a software interrupt of the INT 13h) to be automatically generated when an access request is made (ST10). .

The head address save control means (3)
0, 39) are access forced prohibition control means (30, 3).
While the access to the floppy disk drive 40 is forcibly prohibited by the operation of 9), a predetermined memory (for example, the RAM 3
3 is saved in the save memory (in this embodiment, the FD driver address save area 33SA) (ST11).

The detection start address rewriting control means (30, 3)
9) Save access start address (ST11)
Later, the access head address stored in the predetermined memory (33) is replaced with the virus detection driver (30, 3).
Rewrite to the detection start address of 9) (ST12).

Access forced prohibition temporary release control means (3)
0, 39) is the rewriting of the detection start address (ST12).
Later, the forced access prohibition by the forced access prohibition control means (30, 39) is temporarily released (ST13). That is, a substitute interrupt signal that is the same as the interrupt signal prohibited to be generated (for example, the software interrupt of the INT 13h) itself or a substantial interrupt signal (for example, a software interrupt of the INT 13h) is generated. . It is not the generation of a regular interrupt signal.

The virus detection driver drive control means (3)
0, 39) controls to drive the virus detection driver (30, 39) via the detection start address stored in the predetermined memory (33) during the temporary release of the forced access prohibition.

In this embodiment, the access to the virus detection unit in FIG. 3 corresponds to this, and the initial program loader (I) of the floppy disk FD shown in FIG.
PL) and retrieves the relevant floppy disk FD (IP
L) Detects whether the virus is infected (ST14)
I do.

The rewrite control means (30, 39) determines that the detection result by the drive of the virus detection driver (30, 39) indicates that the virus has not been infected (S
At T15 (NO), the detection start address stored in the predetermined memory (33) is returned to the original access head address and rewritten (ST16).

The access forced prohibition release control means (3)
(0, 39) is forcibly prohibiting access to the floppy disk drive 40 by the forcible access prohibition control means (30, 39) after the address rewrite (ST16) (ST1).
0) is released (ST17).

File access permission control means (30, 3)
9) permits access to the original access start address stored in the predetermined memory and the file FL in the floppy disk FD mounted on the floppy disk drive 40 after the release of the forced access prohibition (ST1).
8). That is, the interrupt signal is generated normally. Therefore, the OS (APL) can access the FD file (ST19).

The alarm output control means (30, 39) stores the result in the predetermined memory (33) when the detection result by the drive of the virus detection driver (30, 39) indicates that the virus is infected (YES in ST15). While the detected start address and the access forbidden state are maintained (ST10), an alarm is output to the effect that the floppy disk FD is infected with a virus.

In this embodiment, the electronic buzzer 50 shown in FIG.
To output a voice alarm and display for the operator (CR
T) A display alarm is output to 42 (ST20). It is also possible to output an alarm to a host machine or the like via the online board 45 and the data communication network 5.

In the merchandise sales data processing device (10) of the first embodiment, the cashier mounts the floppy disk FD on the floppy disk drive 40 and operates the key on the keyboard 41 to operate the floppy disk FD.
Request access.

Then, the OS detecting this issues an access request to the floppy disk drive 40. Thereby, the access compulsory prohibition control means (30, 39) forcibly prohibits access to the floppy disk drive 40 (ST10 in FIG. 4).

The access compulsory prohibition control means (30, 3)
During the forbidden access by 9), the head address save control means (30, 39) saves the head address for accessing the floppy disk drive 40 stored in the predetermined memory (33) in the save memory (33SM). (ST11).

Subsequently, the detection start address rewriting control means (30, 39) rewrites the access start address stored in the predetermined memory (33) to the detection start address of the virus detection driver after saving the access start address. (ST12). Then, the access forced inhibition temporary release control means (30, 39) temporarily releases the access forced inhibition (ST10) by the access forced inhibition control means (30, 39) after rewriting the detection start address (ST13).

Here, the virus detection driver drive control means (30, 39) drives the virus detection driver via the detection start address stored in the predetermined memory during the temporary cancellation of the forced access prohibition (ST14).
That is, the virus detection driver (30, 39) is installed in the floppy disk drive 40 (IPL of the FD in FIG. 5).
While referring to the virus pattern storage file 33PM (39PM) storing the pattern of each virus that is involved in the virus and can infect the floppy disk FD (IPL), the floppy disk FD mounted on the floppy disk drive 40 It is detected whether or not it is infected (ST14).

This virus detection driver (30, 3)
If the result of the detection by the driving in step 9) is that the virus is not infected (NO in ST15), the rewrite control means (30, 39) sets the detection start address stored in the predetermined memory (33). To the original access head address and rewrite (ST16).

Then, the forced access prohibition release control means (30, 39) releases the forced access prohibition to the floppy disk drive 40 after rewriting the address (ST17). File access permission control means (30,
39) is the original access start address stored in the predetermined memory after the access compulsory prohibition is released, and the floppy disk FD attached to the floppy disk drive 40 via the floppy disk drive 40.
Are permitted to access each of the files FL1, FL2,... Shown in FIG. 5 (ST18). Thus, each file in the FD can be accessed after confirming that no virus has been infected. (ST19).

On the other hand, the virus detection driver (30, 3)
When it is determined that the detection result by the driving in 9) is that the virus is infected (YES in ST15), the alarm output control means (30, 39) sets the detection start address and the detection start address stored in the predetermined memory (33). While maintaining the access forbidden state, an alarm is output to the effect that the floppy disk FD is infected with a virus (ST20).

Therefore, it is possible to reliably perform a virus check on the floppy disk FD handled in the own device (10). In addition, since the operation is automatically performed when the floppy disk FD is accessed, the handling is easy, and when a virus is infected, an alarm is output in a state where access is forcibly prohibited and the floppy disk is discarded. It is safe because you can.

Further, when there is an access request for the floppy disk FD, the access start address stored in the predetermined memory (33) is rewritten to the detection start address of the virus detection driver (30, 39), and the virus check result is transmitted. In the case where there is no access, since it is configured to return to the original access head address and allow access to the floppy disk FD, priority execution of virus detection can be reliably ensured.

Further, even with a single-task OS, the virus detection task of the floppy disk FD can be prioritized, so that a device (10) employing a relatively simple single-task OS can be constructed, and even in this case, reliable virus elimination can be achieved. Can be guaranteed.

[0057]

According to the first aspect of the present invention, when an access request is issued from the OS, access to the floppy disk drive is forcibly prohibited, and the virus detection driver determines whether the floppy disk is infected with a virus. Is detected, and if the detection result is not infected with a virus, the access prohibition of the floppy disk drive is canceled and the floppy disk is accessible.If the detection result is infected with the virus, the access prohibition of the floppy disk drive is forcibly prohibited. Since the merchandise sales data processing device is formed so as to be able to output an alarm indicating that a virus has been infected while maintaining the same, it is possible to reliably detect a virus infection in a floppy disk handled in its own device.
In addition, since the operation is automatically performed when accessing the floppy disk, it is easy to handle, and when a virus is infected, an alarm is output while the access is forcibly prohibited, so that the floppy disk is discarded. It is safe because you can.

Further, the invention of claim 2 provides a virus pattern storage means, a virus detection driver, an access forced prohibition control means, a head address save control means, a detection start address rewrite control means, an access forced prohibition temporary release control means, a virus detection. When a driver drive control unit, a rewrite control unit, an access forcible prohibition release control unit, a file access permission control unit, and an alarm output control unit are provided, and a detection result by driving a virus detection driver is assumed to be infected with a virus. A product sales data processing device which is capable of outputting an alarm indicating that the floppy disk is infected with a virus while maintaining the detection start address and the access forbidden state stored in a predetermined memory. From the same way as in the first aspect of the invention, Cormorant reliably perform a virus check on the floppy disk. In addition, since it is automatically performed when accessing the floppy disk, it is easy to handle, and if a virus is infected, an alarm is output while the access is forcibly prohibited, so discard the floppy disk It is safe because you can do it. Furthermore, when there is a floppy disk access request, the access head address stored in the predetermined memory is rewritten to the detection start address of the virus detection driver, and if the virus check result indicates no infection, the original access head address is replaced. Since it is configured to allow access to the floppy disk by returning it, priority execution of virus detection can be reliably ensured.

Further, according to the third aspect of the invention, since the OS is of the single task system, the same effects as those of the first and second aspects of the invention can be obtained. A device employing a relatively simple single-task OS can be constructed, and even in this case, reliable virus elimination can be guaranteed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is also an external perspective view.

FIG. 3 is a schematic system diagram for explaining a relationship among an OS, an FD driver, and a virus detection driver.

FIG. 4 is a flowchart for explaining the operation.

FIG. 5 is a schematic diagram for explaining the structure of a floppy disk.

[Explanation of symbols]

Reference Signs List 5 data communication network (LAN) 10 electronic cash register (product sales data processing device) 20 personal computer 30 control unit (virus detection driver, access compulsory prohibition control unit, head address save control unit, detection start address rewriting control unit, access Forced prohibition temporary release control means, virus detection driver drive control means, rewrite control means access forced prohibition release control means, file access permission control means, alarm output control means) 31 CPU 32 ROM 33 RAM (predetermined memory) 33SA FD driver address Save area (save memory) 33PM Virus pattern storage file (virus pattern storage means) 39 Hard disk (virus detection driver, access compulsory prohibition control means, head address save control means,
Detection start address rewriting control means, access forced prohibition temporary release control means, virus detection driver drive control means,
Back rewriting control means access forced prohibition release control means, file access permission control means, alarm output control means) 39 PM virus pattern storage means 40 floppy disk driver FD floppy disk 41 keyboard 42 operator display 50 electronic buzzer

Claims (3)

[Claims] An external information can be installed from a floppy disk mounted on a floppy disk drive so that merchandise sales data processing can be executed using the external information which is dependent on the OS and installed using the floppy disk. In the merchandise sales data processing device formed in the above, when an access request to the floppy disk drive is issued from the OS, the access to the floppy disk drive can be forcibly prohibited, and the virus detection driver is disabled during the access forcibly prohibited. The floppy disk mounted on the floppy disk drive by driving can be detected whether it is infected with virus or not. If the detection result is not infected with virus, the floppy disk drive access prohibition is released. do it If the floppy disk mounted in the floppy disk drive is accessible and the detection result is infected with a virus, the floppy disk is infected with the virus while the access to the floppy disk drive is forcibly prohibited. A merchandise sales data processing device formed to output an alarm to the effect. 2. An external information can be installed from a floppy disk mounted on a floppy disk drive, and a merchandise sales data process can be executed by using the external information which is dependent on the OS and installed using the floppy disk. A virus pattern storage means for storing a pattern of each virus which can infect the floppy disk; and a floppy disk drive which is involved in the floppy disk drive and refers to the virus pattern storage means. A virus detection driver capable of detecting whether or not the floppy disk mounted on the disk is infected with a virus;
S for preventing access to the floppy disk drive when an access request to the floppy disk drive is issued from the S; to a floppy disk drive stored in a predetermined memory while the access is forcibly prohibited; A start address save control means for saving the access start address in the save memory, and a detection start address for rewriting the access start address stored in the predetermined memory to the detection start address of the virus detection driver after saving the access start address. Rewriting control means, access forced prohibition temporary release control means for temporarily canceling access forced prohibition by the access forced prohibition control means after rewriting the detection start address, and detection stored in a predetermined memory during temporary cancellation of access forced prohibition. Start a And a virus detection driver driving control means for driving a virus detection driver via a host computer, and a detection start address stored in a predetermined memory when the detection result obtained by driving the virus detection driver is not infected with a virus. Rewriting control means for rewriting the access start address, rewriting the address forcibly prohibiting the access to the floppy disk drive by the access compulsory prohibition control means after rewriting the address, and predetermined after the compulsory access prohibition is released File access permission control means for permitting access to a file in a floppy disk mounted on the floppy disk drive via the original access head address stored in the memory and the floppy disk drive; If the detection result by driving the bar is assumed to be infected with a virus, the floppy disk is infected with the virus while maintaining the detection start address and the access forbidden state stored in the predetermined memory. And a warning output control means for outputting a warning to the effect. 3. The merchandise sales data processing device according to claim 1, wherein the OS is a single task system.