JPH01300357A - Electronic disk device - Google Patents

Abstract

PURPOSE:To minimize the destruction of the memory contents by discontinuing a data writing action at the trouble of an electronic disk device after reading out the protection information which is stored in the same address as the writing address to a data memory circuit from a control memory circuit. CONSTITUTION:The same addresses are read out of a data memory circuit 15 and a control memory circuit 17 respectively before the data contained in a data signal 12 is written into the circuit 15 based on an address signal 11. Therefore the protection information 19 is read out of the circuit 17 against an address of the circuit 15 that should be protected. When a writing action is carried out to the address where the information 19 on the circuit 17 is stored at the abnormality, i.e., a hardware trouble, etc., the information 19 is detected by a memory control circuit 21. Thus the circuit 21 discontinues the subsequent data writing actions to the circuit 15 by means of the control information 24 and protects the memory contents.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to electronic disk storage, and more particularly to an electronic disk device that can protect memory contents in the event of a malfunction of the device.

[Conventional technology]

Semiconductor integrated circuits have made remarkable progress over the past ten years. Taking microprocessors as an example, they have continued to advance in functionality and performance, from 4 bits to 8 bits to 16 bits to 132 bits. The memory space used by such logic device application devices with higher functionality and performance has become vast, and various types of management have become necessary.

In particular, memory protection is e.g.
This is important in terms of protecting the system (system) from other programs and isolating user tasks from each other. It is also becoming important to prevent the system from running out of control due to erroneously writing data to the area where the program is stored. Conventionally, for example, programs and data have been protected by providing a descriptor that indicates predetermined attributes for each area (segment or page). That is, each time this segment is accessed, the nature of this access, e.g., read, write, or execute, is determined by the attributes set in the descriptor, e.g., read or write, whether execution is allowed or prohibited. will be checked against. When access was violated, a trap was generated and control was transferred to O8. Incidentally, the electronic disk device according to the present invention has not conventionally had a means for detecting and stopping even if writing is performed to an illegal memory area due to a hardware failure or the like.

[Problem to be solved by the invention]

As described above, conventional electronic disk devices have a problem in that when a hardware failure occurs, data is written to an incorrect memory area and the contents of the memory are destroyed.

[Means to solve the problem]

A data memory circuit that stores data, management information, etc., and a control memory circuit that has the same address as this data memory circuit and stores protection information for protecting the stored contents of this data memory circuit in the event of a device failure. , generates the protection information to be stored in the control memory circuit, writes it in advance to the control memory circuit, and in the event of a failure of the device, writes the protection information to the control memory before writing to a desired address in the data memory circuit. Reads the protection information stored in the same address as the write address to this data memory circuit from the circuit,
The memory control circuit includes a memory control circuit that stops the write operation.

Therefore, when using the electronic disk device according to the present invention, the control memory circuit has the same address as the data memory circuit to be protected, and stores protection information for protecting the contents stored in this data memory circuit. The memory control circuit generates the protection information and writes it in the control memory circuit in advance, and in the event of a hardware failure or the like, the memory control circuit generates the protection information and writes the protection information from the control memory circuit before writing to an arbitrary address of the data memory circuit. The protection information stored at the same address as the write address for the data memory circuit is read and the write operation is stopped. Thereby, even if a failure occurs, destruction of the memory contents of the data memory circuit can be minimized.

〔Example〕

The present invention will be described in detail below with reference to Examples.

FIG. 1 shows the electronic disk device of this embodiment.

In the figure, address signal 1 from a higher-level device (not shown)
1 and data signal 12 are connected to interface control circuit 1
4 to the data memory circuit 15. The interface control circuit 14 controls the interface with a host device (not shown). The data memory circuit 15 stores data, management information, etc. included in the data signal 12 described above.

Further, this data memory circuit 15 is connected to a control memory circuit 17.
connected to. This control memory circuit 17 has the same address as the data memory circuit 15 and also stores protection information 19 for protecting the data memory circuit 15. Further, it receives an address signal 11 from a data memory circuit 15. The protection information 19 stored in the control memory circuit 17 is generated by a memory control circuit 21 connected to the control memory circuit 17. This memory control circuit 21 also includes:
It is connected to the data memory circuit 15 and the interface control circuit 14 . The memory control circuit 21 then sends a control signal 23. to the data memory circuit 15 and control memory circuit 17.
24 to control reading and writing to these circuits. Furthermore, this memory control circuit 21 receives a memory read/write control signal 25 from a host device (not shown) via the interface control circuit 14, and its operation is activated.

Next, the operation will be explained.

First, in the initialization process, the protection information 19 generated by the memory control circuit 21 is written into the control memory circuit 17 at regular address intervals according to the control signal 23. Thereafter, a control signal 25 is sent from a host device (not shown) to the memory control circuit 21, whereby the memory control circuit 21 is set and performs the next operation. That is, before the data included in the data signal 12 is written from the host device (not shown) to the data memory circuit 15 according to the address signal 11, the same address of the data memory circuit 15 and the control memory circuit 17 is read, and thereby the control memory Protection information 19 for an address to be protected in data memory circuit 15 is read from circuit 17 . During normal times,
Writing to the data memory circuit 15 is performed to an address in which the protection information 19 is not written to the control memory circuit 17. Therefore, in this case, the memory control circuit 21 does not detect the protection information 19 from the control memory circuit 17, and the write operation continues. On the other hand, in the event of an abnormality, such as a hardware failure, the control memory circuit 17
When writing is performed to the address where protection information 19 is stored, the memory control circuit 21 writes this protection information 19.
Detect. As a result, the memory control circuit 21 uses the control information 24 to stop subsequent data writing to the data memory circuit 15, thereby protecting the memory contents.

〔Effect of the invention〕

As described above, the electronic disk device of the present invention has a control memory that has the same address as a data memory circuit to be protected and stores protection information for protecting the stored contents of this data memory circuit in the event of some kind of failure of the device. generate a circuit and protection information, write this protection information in the control memory circuit in advance, and write to the data memory from the control memory circuit before writing to a desired address of the data memory circuit in the event of a failure of the device. By providing a memory control circuit that reads the protection information stored at the same address as the write address and stops the write operation, destruction of memory contents can be minimized in the event of a device failure such as a hardware failure. effective.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an electronic disk device of the present invention. 15...Data memory circuit, 17...Control memory circuit, 21...Memory control circuit. Applicant: NEC Corporation Representative

Claims (1)

[Claims] A data memory circuit that stores data, management information, etc.; and protection information that has the same address as this data memory circuit and protects the contents stored in this data memory circuit in the event of a failure of the device. a control memory circuit to store the data; and a control memory circuit that generates the protection information to be stored in the control memory circuit, writes it to the control memory circuit in advance, and, in the event of a failure of the device, writes the protection information to a desired address of the data memory circuit. The electronic device further comprises a memory control circuit that reads the protection information stored at the same address as a write address for the data memory circuit from the control memory circuit and stops the write operation. disk device.