JPH11120082A - Computer system and its data storage device, and data protecting method for computer system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the computer system which can securely protect data by allowing direct access from computers to one fixed magnetic disk and limiting access to data, computer by computer. SOLUTION: The computer system is constituted by connecting computer terminal devices 21 and 22 through a local area network 1. Data storage devices 11 and 13 provided to the computer terminal devices 21 and 22 are accessed directly not through the local area network 1. In addition to the said constitution, the data storage devices 11 and 14 are provided with a protect information area 12 which shows the computer terminal devices 21 and 22 are allowed to gain access, and the terminal devices 21 and 22 are allowed to access only data areas 13 of the data storage devices 11 and 14 specified by the protection information area 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer system using a data storage device, a data storage device and a data protection method for the computer system, and more particularly, to data on a fixed magnetic disk or the like accessed from a plurality of computer terminals. The present invention relates to a data protection method for a storage device.

[0002]

2. Description of the Related Art Conventionally, as a data protection method for a magnetic disk drive, for example, as shown in Japanese Patent Application Laid-Open No. 3-165369, a protect bit is provided for each sector.
With this protect bit, data write permission or non-permission was identified. This state will be described with reference to FIG. 5. When the disk 21 is accessed from the computer 21, when a protect bit indicating write-protection is written in the sector format of the disk 11, the access destination computer 21 is The target sector is notified that it is write-protected, and if a protect bit indicating write-protection has not been written, write processing is performed.

In the above-mentioned conventional computer, for example, a computer A and a computer B (not shown) are connected to a single fixed magnetic disk. If it is desired not to permit access to sector 1 to B, this is not possible, and there is a disadvantage that a plurality of computers cannot directly access the fixed magnetic disk from the viewpoint of data protection. When the computer PC (A) and the computer PC (B) are connected to the LAN (local network) as shown in FIG. 6, the computer PC (A) goes to read the file of the computer PC (B). However, since the file data passes through the PCI bus of the PC itself, the PCI bus is occupied by file transfer, and file transfer is slowed down. Also, the processing speed is slow because the PCI bus is occupied by file transfer. There was a disadvantage of becoming.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks of the prior art, to enable a plurality of computers to directly access a single fixed magnetic disk as described above, and to provide each computer with its own It is an object of the present invention to provide a novel computer system capable of reliably protecting data by restricting data access, a data storage device thereof, and a data protection method for a computer.

[0005]

SUMMARY OF THE INVENTION The present invention basically employs the following technical configuration to achieve the above object. That is, the first according to the present invention
As an aspect of the present invention, in a computer system in which a plurality of computer terminal devices are connected via a local area network, a data storage device provided in the computer terminal device is directly connected without passing through the local area network. As a second aspect, as a second aspect, in a computer system including a large-capacity data storage device accessed from a plurality of computer terminal devices, protection information indicating whether or not the computer terminal device can access the data storage device. An area is provided, and each of the computer terminal devices is a computer system that can access only a data area specified by the protect information area.

According to a third aspect, in a computer system having a data storage device directly accessed from a plurality of computer terminals, a protection information area is provided in the data storage device, and a data area of the data storage device is provided. This is a data protection method for a computer system that restricts access from the plurality of computer terminal devices to be accessed by designating, in the protect information area, whether to permit access to each sector.

In this case, the data storage device is provided with a protect information area indicating whether or not the computer terminal device can access, and each of the terminal devices stores the data area of the data storage device designated by the protect information area. It is characterized by only being accessible. Furthermore,
The protect information area includes protect bits corresponding to the number N of sectors in the data area, and based on the N protect bits, only the data area accessible by each of the computer terminal devices is accessed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The computer system, its data storage device, and the data protection method of the computer system according to the present invention adopt the above-mentioned technical configuration. Therefore, as shown in FIG. If the computer 21 is connected, the computer 22
However, when reading a file from the computer 21, the file data does not pass through the PCI bus of the computer 21 itself, so the PCI bus is not occupied by file transfer,
Therefore, the file transfer speed is increased, and the processing speed of the computer 21 is not reduced.

[0009]

Next, a computer system according to the present invention,
Specific examples of the data storage device and the data protection method of the computer system will be described in detail with reference to the drawings. FIGS. 1 to 4 show specific examples of a computer system according to the present invention. In particular, FIG. 1 shows a plurality of computer terminal devices 21 and 22 connected via a local area network 1. In the computer system, each of the computer terminal devices 21 and 22
1 shows a computer system in which the data storage devices 11 and 14 provided in the computer system can be directly accessed without passing through the local area network 1. In addition to the above configuration, the data storage devices 11 and 14 include: A protect information area 12 indicating whether or not the computer terminal device can access is provided. Each of the terminal devices 21 and 22 can access only the data area 13 of the data storage devices 11 and 14 specified by the protect information area 12. And the protection information area 1
2 includes protect bits corresponding to the number N of sectors in the data area 13, and based on the bits selected by the N protect bits, only the data areas accessible by the respective computer terminal devices are accessed. A computer system is shown.

More specifically, as shown in FIG. 1, a computer 21 has a fixed magnetic disk drive 11
Is connected to the fixed magnetic disk drive 1.
I manage 1. The fixed magnetic disk device 14 is connected to the computer 22 and manages the fixed magnetic disk device 14. In this computer system, a plurality of computers are connected by a LAN 1 so that the fixed magnetic disk devices 11 and 12 can be accessed by the plurality of computers.

Accordingly, the computer 21 can access the fixed magnetic disk drive 14 in addition to the fixed magnetic disk drive 11, and similarly, the computer 22 can access the fixed magnetic disk drive 11 in addition to the fixed magnetic disk drive 14. It is possible. Further, in this computer system, the plurality of fixed magnetic disk devices 11 and 14 are directly connected to each other via the controller 40 shown in FIG. 2, and the fixed magnetic disk devices 11 and 14 are connected to the controller 40 without using the LAN 1. Are configured to be directly accessible by a plurality of computers via the Internet.

The fixed magnetic disk devices 11 and 14 are provided with a FAT (FILE ALLOCATION) like the conventional fixed magnetic disk devices.
TABLE) and a protect information area 12. Protect information area 12
Has a protection information area corresponding to each computer on a one-to-one basis.

Referring to FIG. 1, the protection information area 12 will be described in detail. A computer (computer terminal) 22 has an ID 32 as an identifier for the protection information area 12, while the protection information area 12 of the fixed magnetic disk device 11 In the area corresponding to the ID 32 of 12, there is written a protect bit indicating that the computer 22 cannot access the sectors 0, M, and N (shown in black). Therefore, the computer 22 can access the sector M + 1. Similarly, a computer having ID 3X as an identifier indicates that access to sectors 0, M, and N (shown in black) is impossible, and indicates that sector M + 1 can be accessed. It goes without saying that the computer 21 can read and write data in all areas of the fixed magnetic disk device 11 managed by the computer 21.

Therefore, according to the present invention, it is possible to directly access a single fixed magnetic disk drive from a plurality of computers while maintaining security. In particular, in the access, an accessible data area is provided. The security is ensured by restricting Next, a state in which the computer 22 accesses the fixed magnetic disk device 11 and reads a file or data will be described with reference to the flowchart of FIG.

In order for the computer 22 to read a file from the fixed magnetic disk device 11, the controller 4
When the identifier ID32 is transmitted to the ID 0 (step S1), the controller 40 selects a protection information area corresponding to the ID32 of the fixed magnetic disk device 11 (step S2). The controller 40 writes in the protect information area 12 whether or not the sector specified by the FAT area of the fixed magnetic disk device 11 to which the file is to be read and in which the file is written is a readable sector of the computer 22. The determination is made based on the protected bit (step S3). And
If the sector to be read is accessible, the file is read (step S3).

Next, a state in which the computer 22 accesses the fixed magnetic disk device 11, writes data to a file, and adds data will be described with reference to the flowchart of FIG. When the computer 22 sends the identifier ID32 to the controller 40 to write the file in the fixed magnetic disk device 11 (step S5), the controller 40 selects the protection information area corresponding to the ID32 of the fixed magnetic disk device 11 (step S5). S6). When the computer 22 instructs the controller 40 to add a sector to the file to be updated (step S7), the controller 40 finds a writable sector based on the protect bit in the corresponding protection information area (step S8), and stores the data in the sector. Is written (step S9). And finally, the controller 40
Updates the FAT (step S10).

In the above description, the data storage device is described using a fixed magnetic disk device. However, the data storage device may be composed of a large-capacity semiconductor memory device or an optical recording medium such as an optical disk.

[0018]

Since the present invention is configured as described above, the following effects can be obtained. A sector protection information area corresponding to each computer in a one-to-one correspondence is provided in the protection information area, so that when a single fixed magnetic disk device is accessed from a plurality of computers, data can be protected according to each computer. become. Further, since the sector protection information area corresponding to each computer on a one-to-one basis is provided in the protection information area, a plurality of computers can directly access one fixed magnetic disk device while maintaining security. .

[Brief description of the drawings]

FIG. 1 is a diagram showing an entire system of the present invention.

FIG. 2 is a block diagram of a main part of the present invention.

FIG. 3 is a flowchart for reading a file according to the present invention.

FIG. 4 is a flowchart for writing a file according to the present invention.

FIG. 5 is a diagram showing a first conventional example.

FIG. 6 is a diagram showing a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 LAN 11, 14 Fixed magnetic disk unit 12 Protect information area 13 Data area 21, 22 Computer 40 Controller

Claims (9)

[Claims] 1. A computer system in which a plurality of computer terminals are connected via a local area network, wherein a data storage device provided in each of the computer terminals is directly accessible without passing through the local area network. A computer system characterized by being performed. 2. The data storage device is provided with a protect information area indicating whether or not access to the computer terminal device including the self device is possible, and the protect information region includes the data storage device accessible by each of the terminal devices. 2. The computer system according to claim 1, wherein the information of the data area is displayed. 3. The protect information area includes protect bits corresponding to the number N of sectors in the data area, and based on the N protect bits, only the data area accessible by each of the computer terminal devices is accessed. The computer system according to claim 2, wherein: 4. A computer system including a large-capacity data storage device accessed from a plurality of computer terminal devices, wherein the data storage device is provided with a protect information area indicating whether the computer terminal device can access the computer terminal device. A computer system characterized in that the device can access only the data area specified in the protection information area. 5. A protect bit corresponding to the number N of sectors in the data area is written in the protect information area, and based on the N protect bits, only a data area accessible by each of the computer terminal devices is accessed. The computer system according to claim 4, wherein: 6. A data storage device accessible from a plurality of computer terminals, wherein a protect information area indicating whether or not access from the computer terminal device is provided is provided, and each of the computer terminals is provided based on the information in the protect information area. A data storage device for a computer system, wherein a data area accessible to a computer is restricted. 7. The data storage device according to claim 6, wherein the restriction on the access to the data area is restricted for each sector of the data area. 8. In a computer system having a data storage device directly accessed from a plurality of computer terminals, a protection information area is provided in the data storage device, and access is permitted to each sector of the data area of the data storage device. A data protection method for a computer system, wherein access from the plurality of access destination computer terminal devices is restricted by designating whether or not this is the case in the protection information area. 9. The protection information area includes a protection bit corresponding to the number N of sectors in the data area, and based on the N protection bits, only the data area accessible by each of the computer terminal devices is accessed. 9. The data protection method for a computer system according to claim 8, wherein: