JPH0344752A - Ram card data protection system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention provides RAM (Random Access
Regarding the card data protection method (Meo+ory), in particular,
In small general-purpose terminal devices that use RAM cards as external memory, such as laptop-type personal computers, word processors, input/output devices, etc.
The present invention relates to a RAM card data protection method that protects data written in a RAM card from disappearing.

[Conventional technology]

RAM cards are a new type of external memory. Semiconductor memory elements with low power consumption and large storage capacity (
This device was realized through the development of LSI. A RAM card generally includes a static memory for storing data, its peripheral circuitry, and a dedicated battery for storing data. Therefore, the storage performance of the data written on the RAM card depends on the lifespan of the backup battery of the dedicated battery used as the power source for data storage, and to use the stored data permanently, the backup battery must be replaced regularly. is an essential requirement. For this reason, the RAM cards already offered on the market are limited in this regard.

For example, the following data retention strategies are being introduced: That is, (1) A column is provided in the case of the RAM card to write the battery replacement date, and each time the user replaces the battery, the user writes the date of battery replacement in the battery replacement date entry column.

(2) A power supply monitor signal line for detecting the +5■ power supply (battery output) of the RAM card is provided on the interface of the RAM card, and the signal level on this power supply monitor signal line is checked on the processing device side.

Incidentally, the battery life of currently commercialized RAM cards is approximately three years.

Incidentally, known documents related to the technique of backing up memory data using this type of backup power supply include, for example, Japanese Patent Application Laid-Open No. 141057/1982 and Japanese Patent Application Laid-Open No. 61-14
1059, JP-A-61-148553, JP-A-61-151758, and the like.

[Problem to be solved by the invention]

By the way, in the above-mentioned conventional technology, no consideration is given to the reliability of data storage when a RAM card is used as an external memory, resulting in the following problems. Namely.

(1) The user must manage the date of battery replacement for all RAM cards, and the management burden is extremely heavy.Especially when the number of RAM cards in use increases, management is impossible.

(2) For interfaces with a power supply monitor signal line to detect the power supply of the RAM card, the corresponding R
It is effective if it is possible to detect a drop in the signal level of the power monitor signal line while the AM card is in use, but if the RAM card is unused or in storage, Even if the signal level drops, it cannot be detected, and in this case, the reliability of the data stored in the RAM card cannot be guaranteed. Furthermore, in the method of detecting the signal level using the power monitor signal line, the drooping characteristics of the RAM card battery are important.

Current products have a problem in that the drooping characteristics of each battery are not clear.

The present invention has been made to solve these problems.

An object of the present invention is to provide a RAM that can appropriately notify the user that it is time to replace the battery of a RAM card and that can reliably protect data stored in the RAM card.
The purpose is to provide a card data protection method.

The above and other objects and novel features of the present invention will become clear from the description of the present specification and the accompanying drawings.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a data processing device main body that includes a processing control section, an internal memory, a clock mechanism, an input device, and a display device. In a data processing system using a removable RAM card having a backup power supply as an external memory, a registration means registers storage start date data of the RAM card in a predetermined area in the RAM card based on instruction input data from an input device. When reading data from a RAM card,
Read the storage start date data in the card, calculate the period of use based on the date data from the clock mechanism and the storage start date data, compare it with a predetermined threshold, and when the period of use exceeds the predetermined threshold, The present invention is characterized by comprising usage period management means for displaying a message to the effect that the RAM card continuous usage period has expired on a display device.

[Effect]

According to the above means, a data processing system using a RAM card as an external memory is provided with a registration means for registering storage start date data in the RAM card, and a use period management means for the RAM card.

The registration means registers the RA by inputting manual data from the input device.
Register the storage start date data of the 3G RAM M card in a predetermined area within the M card. Furthermore, when reading data from the RAM card, the usage period management means reads the storage start date data in the RAM card and calculates the usage period based on the date data from the clock mechanism and the storage start date data. .

It is compared with a predetermined threshold, and when the usage period exceeds the predetermined threshold, a message to the effect that the RAM card continuous usage period has expired is displayed on the display device.

In other words, when the user starts using the RAM card, specifically when purchasing the RAM card or replacing the battery,
This registration operation performs a data registration operation related to data retention period management.

The registration means registers the storage start date data in a predetermined area set in the RAM card.During normal operation, at the time of startup of the data processing system, at the time of initial reset,
Or when reading data from a RAM card, such as when the RAM card is installed, the usage period management means
The storage start date data registered in a predetermined area in the M card is read out, the usage period is calculated from the read storage start date data and the date data from the clock mechanism, and the calculated usage period and threshold value are calculated. Compare and judge. In the comparative determination, a magnitude relationship is determined between the period of use and a predetermined threshold value, and a message regarding data storability is output. That is, if it is determined that the data storage limit has been reached as a result of the comparative determination, a message is output from the display device to inform the user of this fact.

This allows the user to know in advance that the warranty period for the data storage of the RAM card has expired, and it is possible to continue using the existing data by taking measures such as replacing the battery or copying the data. Become.

〔Example〕

An embodiment of the present invention will be specifically described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a data processing system according to an embodiment of the present invention. In Figure 1, 1
0 is a system bus, and the system bus 10 has a processing control unit 11 . Internal memo January 21 Clock mechanism 13. Input device 1
4. and display device 15 are commonly connected to form a data processing device main body. This data processing device has
A RAM card 16 used as an external memory is further connected to a system bus 10 to constitute a data processing system. The RAM card 16 has a backup power source and is configured to be detachable from the main body of the data processing apparatus.

FIG. 2 is a diagram illustrating a memory map within the RAM card. Referring to FIG. 2, the memory area of the RAM card 16 is provided with a label storage area 1, a data retention period storage area 2, and a file data storage area 3. Label storage area 1 is an area for storing labels related to data stored in the RAM card. The data storage rule 185 storage area 2 stores data regarding the data storage period of data to be stored in the RAM card (data storage start date). Further, the file data area 3 is the original data storage area for storing file data when the R, AM card is used as an external memory. In this way, the memory area of the RAM card is used as the data management area and the label storage area 1.
and a data retention period storage area 2, and a file data storage area 3 as a data storage area.

Next, an overview of the operation of a data processing system using RAM data configured as described above will be explained. When a user uses a RAM card for the first time, the user first performs an operation to register the data storage start date. This g.record operation is performed when the user inputs a registration instruction using the input device 14.
This registration instruction is transmitted to the processing control unit 11 via the system bus 10.

As a result, the processing control unit 11 writes data on the data storage start date to the data storage period storage area 2 (FIG. 2) on the RAM card 16 in accordance with the processing procedure of the data storage start date registration process. .

No. 3181 is a flowchart showing the processing flow of data storage start date registration processing.

Referring to FIG. 3, in this registration process, first.

In step 31, it is determined whether the RAM card has been inserted, and if the RAM card has not been inserted.

Proceeding to step 32, a RAM card set request is displayed and output to prompt the operator to install the RAM card. Then, the process returns to step 31, and the set state of the RAM card is determined again. Also, if it is confirmed in step 31 that the RAM card has been inserted.

Proceeding to step 33, it is determined whether the input method for the data storage start date is automatic. If the input method for the data storage start date is automatic, it will be automatically input from the built-in clock mechanism. Therefore, the process proceeds to step 34, where the date data is read from the clock mechanism, and the process proceeds to the next step 35, where the read date data is written into the data retention period storage area of the RAM card.

On the other hand, in step 33, if the input method for the data storage start date is not automatic, the input of the data storage start date is as follows.
This is done manually by the user using an input device. In this case, the process advances to step 36 to read the manually input date data from the human-powered device, and in step 35 the manually input date data is written to the data retention period storage area of the RAM card, and the process ends.

In this way, the date data manually entered by the user or the date data read out by the 9 clock mechanism can be
Write to the data retention period storage area of the AM card.

The process of writing the date data of the storage start date to be registered into the RAM card of the external memory is to temporarily store the date data (TERMO) to be registered in the internal memory 12,
The address ADRO to be written to the RAM card is designated, and a write command for the data (TERMO) once stored in the internal memory 12 is given to the RAM card to perform the write process.

Note that the write process for such a RAM card is as follows:
By assigning the RAM card address to the address space of the internal memory 12, it is possible to directly write data regarding the data storage start date from the input device 14 to a predetermined area (data storage period storage area) in the RAM card. Become.

FIG. 4 is a flowchart showing the processing flow of data retention period confirmation processing during normal operation. This data retention period confirmation process is performed during normal operation, for example: 1) Immediately after the device is powered on, 2) Immediately after the system reset, 3) Immediately after the RAM card 16 is installed, etc. It is necessary to confirm the retention period of the RAM card 16. When the time is detected, the processing control unit 11 is activated and data retention period confirmation processing is started.

To explain with reference to FIG. 4, 5 In this data retention period confirmation process, in step 41, it is confirmed that the RAM card has been inserted, and then in the next step 42,
The data storage start date (TE
RMO).

Next, in step 43, the clock mechanism outputs the current date and time (
T) is read out, and in the next step 44, the difference between the current time T and the data storage start date TERMO is calculated to calculate the data storage period Tl. In the next step 45, the calculated data retention period T1 is determined 7. G
'IQ is compared with a predetermined threshold value Tth. If it is determined in step 45 that 'rl<Tth, it is determined that the end of the data retention period has not yet been reached and data retention can be sufficiently guaranteed, so this confirmation process is performed. end. Also, step 45
If it is not determined that T1<Tth, the data storage period has almost reached its end, so the process proceeds to step 46, where an alarm is displayed and the process ends. In this alarm display, for example, a warning message is displayed to prompt the user to take data preservation measures such as battery replacement or data copying.

In this way, when you need to confirm the reliability of data immediately after installing a RAM card, immediately after resetting the system, or when using RAM card data, you can check the data storage start date TERMO registered on the RAM card and the clock mechanism. Calculate the data retention period Tl from the difference from the current date and time T of 7E, and compare and judge the calculated retention period T1 with a predetermined threshold value Tth.
It is also possible to set a plurality of threshold levels and, for example, notify the user of the time to replace the battery at an early stage by changing the warning level. An example of the data retention period confirmation process in this case will be described next.

FIG. 5 is a flowchart illustrating an example of data retention period confirmation processing in which the data retention period is determined using a plurality of threshold values. This will be explained with reference to FIG.

In this process, two thresholds ('rth, , Tthl; Ttha>TthL) are used as criteria for determining the data retention period.
) is provided.

In the case of this process as well, the retention period Tl is calculated based on the data retention start date TERMO registered in the RAM card and the current date and time T, following a process flow similar to that shown in FIG. The storage period T1 is determined by a plurality of threshold values Tth, Tth, and different alarm displays are displayed depending on the result of one determination. In other words, in this process, in step 51, the RAM card is already inserted. After confirming this, in the next step 52, R
Data storage start date registered from AM card TERM
Then, in the next step 53, the current date and time T is read out from the clock mechanism. Subsequently, in step 54, the difference between the current date and time T and the data storage start date TERMO is calculated to calculate the data storage period T1. Then, in the next step 55 and subsequent steps, the calculated data retention period T1 is determined and an alarm is displayed.

In step 55, the data retention period T1 and the second threshold T
In this comparative judgment, which performs a comparative judgment with thl,
If it is determined that TlaTth.

Since the data storage period is nearing its end and it is determined that data storage is not guaranteed, the process proceeds to step 58.2 For example, an alarm is displayed requesting battery replacement and data writing to the RAM card is prohibited. The process ends. In addition, in the comparison determination process of step 55, if T1≧T thl is not determined, further step 56
Then, it is determined whether Tthl>T1≧Tth. In the determination at step 56, Tth,>T
l≧Tth.

If so, proceed to step 57 and 1 e.g.

Only an alarm indicating the need for battery replacement is displayed, a display prompting the user to replace the battery is displayed, and the process ends. In this case, access to the RAM card 16 continues to operate normally, and the data stored in the RAM card 16 is also guaranteed. Also.

If it is determined in step 56 that Tthl>Tl≧Tth, the data retention period has not yet reached the end of the data retention period (5), and the data retention is sufficiently guaranteed, so the process is continued. end.

In this way, in the process of confirming the data retention period shown in FIG. 5, the data retention period T1 of the elapsed period and the two thresholds T tho and T t are determined by comparison with the threshold value serving as one criterion.
The relationship with h□.

1) Ttho□ (If Tth□, for example, an alarm indicating that the battery needs to be replaced is displayed, and a message indicating that the storage period is approaching is output to the display device 15, but after that, the RAM card 16 is The RAM card 16 operates normally and the data stored in the RAM card 16 is guaranteed.

2) If T1≧T th, it is determined that the storage period has passed.1 For example, an alarm display requesting battery replacement is displayed, a message to that effect is output to the display device 15, and the RAM card after this is Access to 16 will result in abnormal termination.

Such threshold values (Tth, Ttho, Tth engineering) used as criteria for determining the retention period of data in the RAM card.
can be changed depending on the type of RAM card (type of storage capacity; type of built-in battery). When the storage capacity of the RAM card differs, the power consumption of the built-in static memory element of the RAM differs, and the degree of consumption of the built-in battery also changes. Therefore, the threshold value is changed depending on the type of RAM card. This allows effective data storage management.For example, if the storage capacity of a RAM card is 5.
When the number of bytes is 2, the threshold is set to Ttha, and when the number of bytes is 64, the threshold is set to Tthb (Ttha>Tthb), and the threshold is changed according to the storage capacity.

In this way, since the threshold value changes depending on the type of RAM card, the threshold value of each RAM card is
The configuration is such that it is registered in a predetermined management data area of the card. For example, as shown in FIG.
The threshold value Ttbt shall be set in the threshold value storage area 4 of a specific area of the card 16, and this threshold value Ttbt shall be set at the start of use of the RAM card.
I-Manage writing. The threshold value Tth, which is a criterion for determining the data retention period, is set corresponding to the RAM card 81#I, so each of the threshold values Tth is different. The threshold value of the RAM card is set when the RAM card starts to be used in the same manner as the data storage start date is registered.

The threshold value of the RAM card is determined by inputting an instruction from the user through the input device 14, for example, depending on the type of built-in battery. Alternatively, the determination may be made automatically by a program by checking the effective memory area by a read-after-write check of the RAM card.

An example of the process of writing the threshold value Tth by inputting an instruction of the type of RAM card from the input device will be described with reference to FIG.

FIG. 7 is a flowchart illustrating an example of a threshold value writing process based on input of a RAM card type instruction. To explain the outline of the process, first, in step 61, it is determined whether or not it is an unused RAM card, and the unused RAM card is
Make sure it's a card. In step 62, if it cannot be confirmed that the RAM card is an unused RAM card, the process is terminated, and if it can be confirmed, the process starts from step 62.

Displays a message requesting input of the type of RAM card.

Next, in step 63, the RAM card type input from the input device is read, and in the first step 64, a threshold value Tth is determined based on the input RAM card type.

This threshold value determination processing is performed, for example, by searching a table that defines the correspondence between the type of RAM card and the threshold value Tth and reading out the threshold value data.
Determine. Then, in the first step 65, the determined threshold value Tth is written into the threshold value storage area of the RAM card, and the process ends.

For example, as shown in FIG. 8, there is an inversely proportional relationship with the storage capacity in which the larger the storage capacity, the smaller the threshold value Tth is. Type of RAM card and threshold value Tth
defines the correspondence relationship with

Based on this relationship, the threshold value T for each RAM card capacity is
th is determined. This is because if the storage capacity of the RAM card is large, the amount of power consumed by the built-in backup battery will also be large, and the effective data storage period will be shortened. Therefore, the threshold value that serves as a criterion for determining the effective retention period is defined in an inversely proportional relationship such that the larger the storage capacity, the smaller the threshold value Tth.

Furthermore, when a RAM card is installed and connected to the data processing device, if the power supply from the built-in battery of the RAM data is cut off and the power is supplied from the data processing device instead, the RAM card can be connected. The threshold value Tth, which is a criterion for determining an effective storage period, is increased in accordance with the time the data processing device is connected and used. This corresponds to the power consumption of the built-in battery for RAM data.

Appropriate data retention period management can be performed.

Next, a data processing system according to another embodiment of the present invention will be described.

FIG. 9 is a block diagram showing the configuration of a data processing system according to another embodiment of the present invention. In Figure 9,
10 is a system bus, and a processing control unit 11. Internal memory 122, clock mechanism 13a, input device 14. and display device 15 are commonly connected to form a data processing device main body.

A RAM card 16a used as an external memory is further connected to the system bus 10 in the main body of the data processing apparatus to constitute a data processing system. These configurations are basically the same as the configuration of the data processing system shown in FIG. 1, but an interrupt signal line 17 is connected from the clock mechanism 13a to the processing control section 11. Further, the RAM card connector 18 is provided with a connection detection pin 19 for the RAM card 16a and a power pin 20 for supplying power. In other words, connection detection pin 1
9, the RAM card 16a is connected to the RAM card connector 18
This is a pin that detects that it is connected to the power pin 20.
teeth.

When the RAM card 16a is connected to the RAM card connector 18, the power supply pin cuts off the power supply from the built-in battery of the RAM card 16a and supplies power to the RAM card 16a from the power supply Vcc of the data processing device main body. It is.

In the data processing system configured as described above, the clock mechanism 13a sends an interrupt signal to the processing control unit 11 via the interrupt signal line 17 at each predetermined time unit, for example, at each TR time. The processing control unit 11 has a clock mechanism 13a.
When it receives an interrupt signal from the RAM card connector 18 at predetermined time intervals, it reads the state of the connection detection pin 19 of the RAM card connector 18,
Check whether the RAM card 16a is connected. R.A.
If it is possible to check that the M card is connected, next the threshold value Tth registered in the RAM card is read out, and the RAM
Unit time T of the period when the card's built-in battery is not used
Corresponding to R, the threshold value T of the unit to be increased is added, and the threshold value Tth is obtained by adding the unit threshold value TII.

It is stored in the RAM card again as the next new threshold Tth. Further, while the RAM card is in use, a process similar to the data retention period confirmation process described above (FIGS. 4 and 5) is performed. That is, the initially preset threshold value Tth of the RAM card is increased by the threshold value corresponding to the time when the RAM card was connected to the data processing apparatus main body. The timer interrupt process for rewriting the threshold value Tth according to the usage time of the RAM card will be explained with reference to FIG. 10.

FIG. 10 is a flowchart illustrating timer interrupt processing for rewriting the threshold value according to the connection time of the RAM card to the main unit. This process is started by a timer interrupt every TR time. When the process starts, first, in step 66, data in the connection detection bin of the RAM card is read, and in the next step 67, it is determined whether the RAM card is connected. 1 or 7 if no RAM card is connected. Exit this interrupt processing. If a RAM card is connected, in step 68,
Read the threshold value Tth of the RAM card, and step 6
In step 9, the threshold value T@ in the unit of increase is added to the threshold value Tth, and this is set as the new threshold value Tth, and step 7
0, the data is written to the RAM card again and the timer interrupt processing ends.

In this case, as is clear from the explanation of the processing example above, the value of the threshold 'rth for comparing and determining the data retention period is RA
It increases according to the usage time of the M card, and the relationship between the usage time of the RAM card and the threshold value Tth is in direct proportion as shown in FIG.

In addition, the threshold value Tth that is set when the RAM card starts to be used is set according to the type of RAM card, written in a specific area of the RAM card, and updated by adding the threat position threshold values T and l according to the usage time. By doing so, the threshold value Tth of the RAM card may be changed. In this case, the threshold value Tth of the RAM card will be changed depending on the combination of the type of RAM card and the usage time.

By the way, in the above-mentioned embodiment, the data storage start date that is registered when the RAM card starts to be used is
When writing to a predetermined data retention period storage area in the M card, the data is written to one specific location in the data retention period storage area.

When writing the data storage start date to the RAM card, for example, as shown in the memory map in Figure 12, write the address AD
The configuration may be such that the same content is written to multiple N locations of RO"ADR (n-1). In this case, when checking the data retention period.

When all data written to N locations are equal.

If a method is adopted in which it is determined that the data in the RAM card is correctly stored, the reliability of the data in the RAM card itself can be checked in conjunction with the determination of the data retention period for the RAM card.

FIG. I3 is a block diagram showing the configuration of a data processing system according to another embodiment of the present invention.

In FIG. 13, 22 is a terminal device, and 25 is a host device. A terminal device 22 is connected to the host device 25 to constitute a data processing system. The terminal device 22 has a processing control unit 11 . Internal memory 12° input device 149 display device i! L5. RAM card 16. and an interface control section 21 are commonly connected. Further, the host device 25 is equipped with an interface control section 23 and a clock mechanism 24.

Similar to the data processing system shown in FIG. 1, the terminal device 22 includes a RAM card 16 used as an external memory.
The host device 25, which is commonly connected to the system bus 10 but is not provided with a clock mechanism, is equipped with an interface control unit 232 and a clock mechanism 24.
In this data processing system, the terminal device 22 is provided with an interface control section 21 for connecting to the host device 25.

By downloading data from the clock mechanism 24 in the host device 25, it is used to manage the data retention period of the RAM card. That is, this data processing system is composed of a terminal device 22 equipped with a RAM card 16 but without a clock mechanism, and a host device 25 equipped with a clock mechanism 24. .

Current date data used to determine the data retention period in the RAM card, time data such as data retention start date data set when the RAM card starts to be used, are sent to the upper layer via the interface control unit 21.23. device 25
It is obtained by downloading from the clock mechanism 24 of.

In addition, in a data processing system composed of a terminal device and its higher-level device, even if the terminal device is not equipped with a clock mechanism, the necessary date and time data can be downloaded from the higher-level device. Therefore, when a RAM card is used as an external memory in each terminal device, data protection can be applied to manage the expiration date using the RAM card data protection method of this embodiment described above.

The present invention has been specifically explained above based on examples, but
It goes without saying that the present invention is not limited to the above-mentioned embodiments, and can be modified from time to time without departing from the spirit thereof.

〔Effect of the invention〕

As described above, the RAM card data storage protection system of the present invention provides the following effects. Namely.

(1) The user does not need to be particularly aware of the storage quality of data stored in the RAM card; an alarm is displayed when the data is used, allowing the user to know the data storage expiration date, thereby preventing data loss due to accidental expiration. be able to.

(2) Also, if the data retention period is approaching,
Users can know this when using normal RAM data, and an error is reported for accessing the RAM card just before the expiry of the data storage period, so data loss can be more reliably prevented. (This greatly improves usability.)

(3) Furthermore, since it is possible to detect destruction of data recorded on the RAM card during the period of use, reliability is improved.

When performing such RAM card data protection, data and system reliability can be improved at low cost without particularly requiring new hardware.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a data processing system according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a memory map in a RAM card. FIG. 3 is a diagram showing data storage start date registration. Flowchart showing the processing flow of the process. FIG. 4 is a flowchart showing the processing flow of the data retention period confirmation process during normal operation. FIG. 5 is the data retention period confirmation process in which the data retention period is determined using multiple threshold values. FIG. 6 is a diagram illustrating another example of the memory map in the RAM card. FIG. 7 is a flowchart illustrating a processing example of a threshold value writing process by inputting an instruction of a RAM card type. FIG. 8 is a diagram for explaining the correspondence between types of RAM cards and threshold values Tth, and FIG. 9 is a block diagram showing the configuration of a data processing system according to another embodiment of the present invention. FIG. 10 is a flowchart illustrating timer interrupt processing for rewriting the threshold value according to the connection time of the RAM card to the main device, and FIG. 11 is a flowchart illustrating the usage time and threshold value of the RAM card according to another embodiment of the present invention. FIG. 12 is a diagram illustrating another example of the memory map in the RAM card. FIG. 13 is a diagram illustrating the configuration of a data processing system according to another embodiment of the present invention. It is a block diagram. In the figure, 1... Label storage area, 2... Data retention period storage area, 3... File data storage area,
10... System bus, 11... Processing control unit, 12
...Internal memory, 13.13a, 24...Clock mechanism, 14...Input device, 15...Display device, 1G
, 16a-RAM card, 21. 23... Interface control unit, 22... Terminal device, 25... Upper device.

Claims (1)

[Claims] 1. A removable RAM card with a backup power source is externally connected to the data processing device main body, which includes a processing control section, an internal memory, a clock mechanism, an input device, and a display device. In a data processing system used as a memory, there is a registration means for registering storage start date data of a RAM card in a predetermined area in a RAM card based on instruction input data from an input device, and a registering means for registering storage start date data of the RAM card in a predetermined area in the RAM card according to instruction input data from an input device; reads out the storage start date data of the RAM, calculates the period of use based on the date data from the clock mechanism and the storage start date data, compares it with a predetermined threshold, and when the period of use exceeds the predetermined threshold, the RAM is A RAM characterized by comprising usage period management means for displaying a message to the effect of expiration of the card continuous usage period on a display device.
Card data protection method. 2. The usage period management means calculates the usage period based on the storage start date data registered in a predetermined area in the RAM card and the date data from the clock mechanism, and when comparing it with a predetermined threshold value, 2. The RAM card data protection system according to claim 1, wherein a plurality of threshold values are set, and an alarm is displayed and access to the RAM card is prohibited depending on the results of comparison with the plurality of threshold values. 3. The plurality of thresholds are two thresholds, the first threshold Tth_■ and the second threshold Tth_1 (Tth_■<Tth_1), and the comparison result is greater than or equal to the first threshold Tth_■ and less than the second threshold Tth_1. In this case, a warning message is output to the display device each time a write/read operation is performed on the RAM card, and if the comparison result is a value greater than or equal to the second threshold Tth_1, the system outputs a warning message to the RAM card. 3. The RAM card data protection method according to claim 2, wherein an error message is output to a display device at the same time as access is prohibited. 4. The registration means is characterized in that, when registering the storage start date data in a predetermined area in the RAM card, a plurality of blocks are provided in the predetermined area, and the same content is written in all blocks of these multiple blocks. R according to claim 1
AM card data protection method. 5. The usage period management means calculates the usage period based on the storage start date data registered in a predetermined area in the RAM card and the date data from the clock mechanism, and compares it with a predetermined threshold;
When comparing usage periods, the RAM is
5. The RAM card data protection system according to claim 4, wherein it is determined that the data in the card is correctly saved, and in other cases, an error message is output. 6. The RAM according to claim 1, wherein when a RAM card is used in a data processing device main body connected to a host device, the registration means registers date data by downloading from the host device. Card data protection method. 7. The threshold used to compare and judge the usage period calculated from the storage start date data stored in a predetermined area in the RAM card and the date data from the clock mechanism is set according to the type of RAM card. The RAM card data protection system according to claim 1. 8. The threshold value used to compare and judge the usage period calculated from the storage start date data stored in a predetermined area in the RAM card and the date data from the clock mechanism should be changed according to the usage frequency of the RAM card. Claim 1
RAM card data protection method described in . 9. The threshold value used to compare and judge the usage period calculated from the storage start date data stored in a predetermined area in the RAM card and the date data from the clock mechanism depends on the combination of the RAM card type and usage frequency. 2. The RAM card data protection method according to claim 1, wherein the RAM card data protection method is changed. 10. A RAM card used in the RAM card data protection system according to claim 1, characterized in that the RAM card is provided with an area for storing storage start date data. 11. A RAM card used in the RAM card data protection system according to claim 1, characterized in that the RAM card is provided with an area for storing storage start date data and a threshold value. 12. In a data processing system composed of a terminal device and its host device, the terminal device is provided with data protection for managing expiration dates using the RAM card data protection method according to any one of claims 1 to 9. RAM
A data processing system characterized by using a card as an external memory.