JPH04114227A - Fixed disk device logical block division method - Google Patents

Abstract

PURPOSE:To improve the reliability of data protection by dividing a logical block into the number of host computers to be used, allocating a logical block address from '0' for each divided logical block and accessing those respective logical blocks only from the host computer having the address of a correspondent bus. CONSTITUTION:The logical block of a fixed disk device 1 is divided into the number of host computers 2 to be used, the logical block address is allocated from '0' for each divided logical block, and those respective logical blocks can be accessed only from the host computer 2 having the address on the correspondent bus. Therefore, the respective host computers 2a-2c on the bus are equipped with the exclusive logical blocks in one fixed disk device 1 so as to inhibit that the other host computer performs access to this exclusive logical block. Thus, the reliability of disk protection can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fixed disk device that serves as an external storage device for a convenience store.

2. Description of the Related Art In general, fixed disk devices are accessed (read, write, etc.) by specifying a logical block address in a command. This logical block address is converted into a cylinder address, head address, and sector address inside the device.

The number of logical programs (capacity jt) that can be accessed on a fixed disk is determined by the number of cylinders, heads, and sectors, as well as the number of sectors in the area used by the device and the spare area.

FIG. 3 is an explanatory diagram showing a schematic numerical configuration of a system in which a plurality of host computers are connected to a fixed disk device via a bus. In FIG. 3, 1 is a fixed disk device, and 2a to 2c are host computers connected to this fixed disk device 1 via a bus 3.

Conventionally, when the number of logical blocks in the fixed disk device 1 is, for example, 700.000, the logical block address of the logical block is fixed to 0 to 699.999.

Next, a conventional logical block access operation will be explained. As shown in FIG. 3, in a certain fixed disk device 1,
A system in which a plurality of host computers 2a to 2C are connected by a bus 3, and each host computer 2a to 2C divides and uses a logical block, in which a plurality of different host computers 2a to 2C use the same logical block. Consider protecting it from access.

Conventionally, in such a case, there is a method in which the areas of logical blocks that can be accessed are determined for each of the host computers 2a to 2C on the bus 3, as shown in FIG.

For example, the host computer 2a whose address on the bus 3 is "1" is connected to the fixed disk device 1 as shown in FIG.
The host computer 2b whose address is "2" on the bus 3 accesses areas 1a from 0 to 99,999 of the logical blocks of the fixed disk device 1.
Areas 1b from 0,000 to 199,999 are accessed.

Alternatively, even if it is not originally divided, if the areas that each host computer 2a to 2C wants to access can be reserved, other host computers 2a to 2C can
C cannot be accessed.

In this way, even in a conventional fixed disk device, the above method can prevent a plurality of host combinations from accessing the same logical block.

Problems to be Solved by the Invention However, in the above-mentioned conventional logical block division method for a fixed disk device, each host computer must add an offset value in order to calculate the logical block that it accesses.

For example, the host computer 2a whose address on the bus is "1" has an offset value of "0", and the host computer 2b whose address on the bus is r2J has an offset value of riot, 0OOJ.

In addition, considering that the system configuration is changed and the addresses of each host computer 2a to 2C are changed, each host computer 2a to 2C always maintains an address on its own bus 3, and from that address logical block must be calculated.

Furthermore, due to the reservation, other host computers 2a
2C can be prohibited from accessing, but if the other host computers 2a to 2C reset the bus 3, the reserved state will be cleared.

In other words, unless the use of bus reset is prohibited within the system, the reserve function becomes meaningless. However, in reality, bus reset is effective when recovering from some kind of failure or when a privileged host computer forcibly terminates use of the bus, and there are disadvantages to prohibiting it.

The present invention solves these conventional problems, and each host computer on the bus has its own logical block in one fixed disk device, and other computers have access to this own logical block. The host computer can be prevented from accessing the host computer, thus
In addition to improving data protection, each host computer can use logical block access from 1 and 0 without being aware of the offset value, and each host computer can issue a bus reset at will. The object of the present invention is to provide a logical block division method for a fixed disk device.

Means for Solving the Problems In order to achieve the above object, the present invention specifies the number of host computers using a fixed disk device by a switch provided in the fixed disk device, and specifies the logical blocks of the fixed disk device. It is divided by the number of host computers to be used, and a logical block address is assigned from O to each divided logical block, so that each logical block can be accessed only by the host computer having the address on the corresponding bus.

According to the present invention, each host computer on the bus has its own logical block in one fixed disk device, and other host computers are prohibited from accessing this own logical block. Therefore, the reliability of data protection can be improved, and each host computer can use logical block access from "0" without being aware of the offset value, and each host computer can arbitrarily reset the bus. can be issued.

EXAMPLE Below, an example of the present invention will be explained in detail with reference to FIGS. 1 to 3.

1 and 2 illustrate a plurality of host computers 2a to 2 shown in FIG. 3 for explaining one embodiment of the present invention.
FIG. 3 is an explanatory diagram when a logical block of the fixed disk device 1 is divided by a host computer 2 (hereinafter generally described as a host computer 2).

Reference mark 11 in Figure 1 and reference mark 21 in Figure 2
is a logical block of a fixed disk device 1 to which a plurality of host computers 2 are connected via a bus 3 as shown in FIG.

This fixed disk device 1 includes switches (not shown) for specifying the number of host computers 2 on the bus 3.
When the number of host computers 2 to be connected is specified by this switch, the fixed disk device 1 receives access from that number of host computers 2 in order from address "1" on the bus 3. It is now allowed.

Now, assume that the number of logical blocks is, for example, 700,000.

Here, if the number of host computers 2 is specified as "7" by the switch of the fixed disk device 1, then the bus 3
The addresses "1" to "7" above are valid, and the addresses of the logical blocks 11 in the fixed disk device 1 that can be accessed by each host computer 2 are 0 to 99,999, as shown in FIG.

On the other hand, if the number of host computers 2 is specified as ``2'' by the switch of the fixed disk device 1, addresses ``1'' to ``2'' on the bus 3 are valid, and as shown in FIG. The addresses of the logical blocks 21 in the fixed disk device 1 that can be accessed by the host computer 2 are 0 to 349999.

In this case, even if there is a host computer 2 with address "3" on bus 3, the fixed disk device 1 will not allow access from host computer 2 with address "3" on bus 3. , when a command to check the number of logical blocks is issued, the number of logical blocks is returned as 0 (none).

Effects of the Invention As described above, the present invention specifies the number of host computers that use a fixed disk device using a switch provided in the fixed disk device, and divides the logical blocks of the fixed disk device by the number of host computers that use the fixed disk device. death,
A logical block address is assigned starting from 0 for each divided logical block, and each logical block can be accessed only by the host computer with the corresponding address on the bus, so each host computer on the bus has one You can have your own private logical block in the fixed disk device of your computer, and prevent other host computers from accessing this private logical block, which improves the reliability of data protection. , each host computer can use logical block access from "0" without being aware of the offset value, and each host computer can issue a bus reset at will.

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams of logical block addresses of a fixed disk device applied to the logical block division method of a fixed disk device according to an embodiment of the present invention, and FIG. FIG. 4 is an explanatory diagram showing a schematic numerical configuration of a system in which a plurality of host computers are connected via a logical block 1 of a conventional fixed disk device.Fixed disk device 2...2a ~2 C... host computer, 3... bus, 11. 21. Logic bunk. Fixed disk unit logical blocks

Claims (1)

[Claims] The number of host computers that use the fixed disk device is specified by a switch provided in the fixed disk device, the logical blocks of the fixed disk device are divided by the number of host computers that use the device, and each divided logical block is Assign a logical block address from 0 to
A method for dividing logical blocks in a fixed disk device so that each logical block can be accessed only by a host computer with an address on the corresponding bus.