JPH02291040A - Electronic equipment - Google Patents

Abstract

PURPOSE:To avoid the destruction of information by comparing a check sum when a power source is turned on with a check sum when it is instructed to turn off the power source, deciding a check sum error and limiting an access to a file corresponding to the decided check sum error. CONSTITUTION:When it is instructed to turn off a power source 5, an arithmetic means 1 calculates the check sum for stored data and program in an internal memory 6 and the calculated check sum for the time of the power source turning off instruction is stored to the internal memory 6. When the power source 5 is turned on, the arithmetic means 1 calculates the check sum again for the data and program stored in the internal memory 6. When the power source 5 is turned on, the check sum to be calculated by the arithmetic means 1 is compared with the check sum, which is written to the internal memory 6, when it is instructed to turn off the power source 5. Then, the check sum error is detected and decided. In correspondence to the result of this decision, the access to the file corresponding to the check sum error is limited. Thus, the destruction of the information on the internal memory 6 can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic device having a memory backed up by an internal power supply, and more particularly to an electronic device that self-diagnoses the storage state of the memory.

[Conventional technology]

Conventionally, as this type of device, for example, Japanese Patent Application Laid-Open No. 63-499
In the electronic equipment disclosed in Publication No. 52, etc., a Handy terminal device executes various information exchange processes with a host computer using a communication line, stores desired data in memory, reads it out at any time, and processes it. In many cases, the configuration is such that this is possible. Particularly, in electronic devices that do not have an external storage device, such as a hard disk or floppy disk, data and programs stored in internal memory are stored and managed using a backup power source.

At the initial stage when the power is turned on, the entire contents of the internal memory are diagnosed by calculating a checksum or the like.

[Invention or problem to be solved]

However, with recent advances in electronic technology, the degree of integration of semiconductor memories has improved, and the storage capacity of memory media used as internal memories has rapidly increased.

Therefore, if a checksum error is diagnosed as a result of checking the authenticity of the checksum using the conventional method of diagnosing the storage status of contents using a checksum of the entire internal memory, the entire contents of the internal memory will become unusable and valuable. There was a serious problem in that data and programs could be lost.

This invention was made in order to solve the above problems, and by storing data and programs stored in internal memory as independent files, and calculating checksums for each file individually. The object of the present invention is to provide an electronic device that can avoid the inability to execute programs and the inability to read data to the entire system due to the DEX Samurai.

[Means for Solving the Problems] An electronic device according to the present invention includes a calculation means for individually calculating a file-by-file sum of data and programs stored in an internal memory at the time of power-off instruction or power-on; The writing means writes the checksum calculated by the calculation means when the power is turned on to the internal memory, and the checksum calculated by the calculation means when the power is turned on is compared with the checksum written to the internal memory by the writing means when the power is turned off. The present invention is provided with a determining means for determining a checksum error and a restricting means for restricting access to a file corresponding to a checksum error determined by the determining means.

[Effect]

In this invention, when a power-off instruction is given, the calculation means calculates a checksum of the data and program stored in the internal memory, and the calculated checksum at the time of the power-off instruction is stored in the internal memory by the writing means. Then, when the power is turned on, the calculating means again calculates the checksum of the data program stored in the internal memory. Here, the determining means compares the checksum calculated by the calculating means when the power is turned on with the checksum written in the internal memory by the writing means at the time of the power-off instruction, and detects and determines a diexum error. Depending on the result of this determination, the restriction means restricts access to the file corresponding to the checksum error to avoid destruction of information on the internal memory.

〔Example〕

FIG. 1 is a block diagram illustrating the configuration of an electronic device showing an embodiment of the present invention, in which 1 is a CPU, a system RO
The entire system is controlled according to the system program in M7. 2 is a key port for manually inputting data, commands, etc. to the running program. 3 is the display,
Displays messages such as system status, human input data, system errors, memory errors, etc. associated with program execution.

Reference numeral 4 denotes a power supply control roll circuit, which controls the output of the battery 5 serving as the power supply. Reference numeral 6 denotes an internal memory (memory) composed of, for example, a RAM, to which a predetermined potential is applied by a backup power supply 10, and the stored contents are always retained even if the power supply control circuit 4 turns off the system power supply.

The system ROM 7 stores checksum processing procedures shown in FIGS. 3 and 4, which will be described later, in addition to various system programs.

A communication port 1.8 inputs data from an external device such as a port (not shown) to the system bus 9 via a communication line, and also transfers data from an electronic device to the communication line.

Note that the CPU 1 includes a writing means, an arithmetic means, and a calculating means of the present invention.
It also serves as a determining means, a limiting means, etc., and calculates the checksum of the data program stored in the internal memory 6 at the time of the power-off instruction, and stores the calculated checksum at the time of the power-off instruction in the internal memory 6 by the CPU 1. . Then, when the power is turned on, CPU 1 or internal memory 6
Calculates the exxsum of the data and programs stored in the . Here, the checksum calculated by the CPU 1 when the power is turned on is compared with the checksum written in the internal memory 6 at the time of the power-off instruction, and a checksum error is detected and determined. Depending on the result of this determination, the CPU i restricts access to the file corresponding to the checksum error, thereby avoiding destruction of information on the internal memory 6, as will be described later.

FIG. 2 is a schematic diagram illustrating a memory map of the memory 6 shown in FIG.
It stores the management information necessary to manage files as files. A program file 1213 stores a created or transferred program. 14
．． A data file 15 stores created or transferred data. 16 is an empty area, which is a usable storage area. Note that the file management process is described in detail in Japanese Patent Application Laid-Open No. 63-49953, etc., so a description thereof will be omitted.

Next, Figure 3. The checksum error determination processing operation according to the present invention will be explained with reference to FIG.

3 is a flowchart illustrating an example of a thumb processing procedure.

Note that (1) to (5) indicate each step.

When an operator or an application program instructs to turn off the power, this flow is started, and the directory section 11 in the memory 6 is searched (1) to select a valid file. Next, it is determined whether checksum calculation has been completed for all valid files (2), and if YES, the power is turned off (5) and the process ends.

On the other hand, if the judgment in step (2) is NO, calculate the checksum for each file (3),
Save the calculated results in the corresponding directory section 11 (4) and return to step (1).

In this way, the checksum for each file on the memory 6 is calculated immediately before the power is turned off, and the checksum regarding the latest file status is stored in the memory 6 by the backup power supply 10.

FIG. 4 is a flowchart illustrating an example of a checksum processing procedure at power-on according to the present invention. In addition,(
1) to (9) indicate each step.

First, when the power is turned on, a valid file on the memory 6 is searched by referring to the management information on the directory section 11 (l), and it is determined whether checksum judgment has been completed for all files (2). ), if NO, calculate the checksum of each file (3) and check individually whether the checksum of the file saved when the power was turned off and the checksum of the file calculated when the power was turned on match. (4) If they match (YES), return to step (1); if NO (if the file contents have been destroyed for some reason), set an error flag (5) and return to step (1) Return to

On the other hand, if the determination in step (2) is YES, it is determined whether an error file with an error flag set exists (6), and if NO, the process proceeds to step (9) and the application program is executed.

On the other hand, if the judgment in step (6) is YES, an error message is displayed on the display 3 (7), and the program execution is temporarily stopped (system execution is temporarily stopped) (8)
．． Wait for instructions from the operator.

In the above embodiment, a case has been described in which a checksum is used as a means for confirming the storability of the memory 6, but the determination information is not limited to the checksum, and other means such as a CRC check can be used. This type of determination processing is included in the technical idea of the present invention.

Furthermore, in the above embodiment, when a checksum error occurs during the flow shown in FIG. 4, the system is temporarily stopped and waits for instructions from the operator. If you run the program and make it notify you of an error when it detects access to a file where an error has occurred,
If there is an error in a data file that does not affect system execution, unnecessary system stoppage can be avoided. Furthermore, if a file in which a checksum error has occurred once is checked in advance to avoid checksum calculation, the checksum error division can be shortened.

〔Effect of the invention〕

As explained above, the present invention provides a calculation means for individually calculating the graphic sum of data and programs stored in an internal memory for each file when the power is turned off or turned on, and a calculation means that calculates the graphic sum of the data and programs stored in the internal memory individually for each file when the power is turned off or turned on. a writing means for writing into the internal memory; and a determining means for determining a checksum error by comparing the checksum calculated by the calculating means when the power supply is being processed with the checksum written to the internal memory by the writing means at the time of the power cut instruction. and a restriction means that restricts access to files corresponding to checksum errors determined by this determination means, so that files that are saved in the memory for some reason while the power of the electronic device is turned off are provided. If the data in the program is destroyed, the damage caused by program execution can be minimized.

Therefore, excellent effects such as being able to predict and deal with malfunctions and abnormalities caused by the execution of application programs in advance are achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram illustrating the configuration of an electronic device showing an embodiment of the present invention, FIG. 2 is a schematic diagram illustrating the memory module of the memory shown in FIG. 1, and FIG. 3 is a power supply according to the present invention. FIG. 4 is a flowchart illustrating an example of a checksum processing procedure at power-on according to the present invention. ] in the figure is CPIJ, 2 is the keyboard, 3 is the display, 4
is the power supply controller 1-roll circuit, 5 is the battery, 6 is the memory, 7
8 is a communication board 1., 9 is a system bus, and 10 is a backup power supply. Figure 5

Claims (1)

[Claims] In an electronic device that reads and executes the data and programs based on an internal memory to be backed up and management information that manages the data and programs stored in this internal memory in file units, the data and programs stored in the internal memory are read and executed. calculation means for individually calculating the checksum of each file for each file when the power is turned off or when the power is turned on; a writing means for writing the checksum calculated by the calculation means when the power is turned off in the internal memory; determining means for determining a checksum error by comparing the checksum calculated by the calculating means with the checksum written in the internal memory by the writing means at the time of the power-off instruction; and a check determined by the determining means. An electronic device comprising a restriction means for restricting access to a file corresponding to a thumb error.