JPH0546563A - Data erasion system for data storage - Google Patents

Abstract

PURPOSE:To free a user from the troublesome jobs by erasing automatically the undesired data that have the low using frequency compared with a period passed. CONSTITUTION:Aperiod TDIF=TO-TDIF, i.e., the difference between the present time TO and the latest using date TNX is referred to for each data. If this period is longer than 8 prescribed period AO, the using count frequency UNX of the relevant data is divided by the period TDIF. When this dividing result alphaN=UNX /TDIF is smaller than the prescribed value betaO, the relevant data is automatically erased out of a RAM.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable data storage device such as an electronic notebook, an electronic memo or a pocket computer, from among a large number of registered data groups.
It relates to a system that deletes infrequently used data for the elapsed period.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a schematic electrical configuration of a conventional portable data storage device.

In the figure, 1 is a CP that controls the entire control.
U and 2 are ROs storing programs for control
M, 3 are RAM as a working memory, 4 is RAM
Reference numeral 3 is a backup power source, 5 is a key input device, and 6 is a display device such as a liquid crystal display panel.

Data (for example, an address book or a telephone number) input by the key input device 5 while being displayed on the display device 6 is written in the RAM 3 by a write command operation on the key input device 5.

In the RAM 3, as shown in FIG.
A large number of data that have been sequentially input are D ₁ , D ₂ , D ₃ ...
It is stored as D _n , D _{n + 1} ....

As the number of times the data storage device is used increases, the number of data stored in the RAM 3 also increases. However, the storage capacity of the RAM 3 naturally has a certain limit. Therefore, unless the old data is deleted, the new data to be registered next cannot be stored.

Therefore, the user searches the data group that has already been stored for the data that may be deleted. The search is performed by first checking the data title list and displaying the data on the display device 6 to confirm whether the data is unnecessary data that may be actually deleted. Take a look. If the data is rarely used in the past and is unnecessary and can be erased, the user performs an erase command operation on the key input device 5. Then, the CPU 1 erases the erase-designated data from the RAM 3. If the data should not be deleted, continue the work,
Search for data that can be erased.

[0008]

As described above, in the conventional data storage device, the number of registered data increases cumulatively as the number of times of use increases unless the user intentionally deletes the data. Then, the area that can be stored gradually decreases, and eventually new data cannot be registered.

Therefore, as described above, the data which seems to be unnecessary is erased by the intention of the user, but it is extremely troublesome and time-consuming to find out the unnecessary data which may be erased from a large number of registered data. It has to be work. Further, there is a possibility that data that is frequently used and should not be deleted may be deleted due to some misunderstanding or erroneous operation.

The present invention was devised in view of such circumstances, and automatically unnecessary data (data that is rarely used for the elapsed period) without depending on the user's will or work. The purpose is to free users from the troublesome work of erasing unnecessary data.

[0011]

A data erasing system in a data storage device according to the present invention counts up and stores the number of times each data is used for each of a plurality of data registered in a memory. , The most recently used date of each data (latest used date) is stored, the difference between the present and latest used date is calculated for each data, and if the difference period is equal to or longer than a predetermined period, the Divide the usage count of the data by the difference period,
When the division result is less than a predetermined value, the data is automatically erased from the memory.

[0012]

The data whose difference between the present date and the latest use date is less than the predetermined period is registered and saved as it is. For data where the difference period is more than the specified period,
[Usage count] / [Difference period] is compared with a predetermined value, and data exceeding the predetermined value is registered and saved as it is, but data less than the predetermined value is less frequently used for the elapsed period. So it will be automatically erased from memory.

If the memory is configured to store the time information at the time of the reset operation at the time of the reset operation for erasing all the data registered in the memory, the all-clear date and time is used as a reference. It is possible to estimate what caused the deletion of all the stored contents.

[0014]

Embodiments of the data erasing system in the data storage device according to the present invention will be described in detail below.

FIG. 1 is a block diagram showing the electrical configuration of a portable data storage device.

In the figure, reference numeral 11 is a CP that controls the entire control.
U and 12 are ROs storing programs for control
M, 13 are RAMs as working memory, 14 is R
A backup power source for the AM 13, 15 is a key input device, 16 is a display device such as a liquid crystal display panel, 17 is a time measuring device (timer), and 18 is a material source. Timing device 1
7, the time is measured in units of year, month, day, hour, minute, and second. However, in the data erasing operation which will be described later, the calculation in units of years and months is sufficient.

When data is registered in the RAM 13, an arbitrary material in the material source 18 may be read and registered by a read command operation by the key input device 15, or C by a key input operation by the key input device 15.
The PU 11 itself may create a material and register it in the RAM 13.

When registering this data, the CPU 11
The time information (year / month / day / hour / minute / second) is read from the timer device 17, and the data is registered in the RAM 13 with the time information attached.

At the same time, "0" is added and registered as the usage count number. Such registration of the data integrated with the time information and the use count number of "0" is performed for each individual data.

Each data can be read out by the read operation on the key input device 15 and displayed on the display device 16. Each time the CPU 11 reads out and displays the data, the CPU 11 counts up the number of times of use of the data by +1 and updates and stores the time information at that time in the RAM 13 as the latest use time information instead of the original time information. become.

FIG. 2 shows an example of the data format in the RAM 13. Data D ₁ , D ₂ , D ₃ , D ₄ , D
₅ are registered in this order.

[0022] The time information T ₁₅ and the usage count the number of times for the data D ₁ "5", the date on which the data D ₁ has been used in the latest (use the latest date) is T _15, moreover, after being first registered , Was the fifth use.

[0023] The time information T ₂₂ and the usage count the number of times of the data D _{2 "2"} is, use the latest date of the data D ₂ is T _22, and, after it has been initially registered, was in use for the second time It shows that.

[0024] The time information T ₃₀ and the usage count the number of "0" for the data D _3, the data D ₃ has never been utilized from when it is first registered, the date of the registration is T ₃₀
And the usage count number remains “0”.

The time information T ₄₃ about the data D ₄ and the number of times of use “3” are the latest use date of the data D ₄ is T ₄₃ , and the third use after the first registration. It shows that.

The time information T ₅₀ about the data D ₅ and the use count number “0” have not been used since the data D ₅ was first registered, and the date of registration is T _50.
And the usage count number remains “0”.

A RAM in such a format
The storage state in 13 is maintained by the backup power supply 14 even if the main power supply is turned off.

Next, an operation for erasing data that is rarely used for the elapsed period will be described with reference to the flowchart of FIG.

This operation is performed every time the main power is turned on. Step S by turning on the main power
The operation from 1 is started. CPU11, step S
At 1, the data number N is initialized to "1". In step S2, stores the usage latest date T _NX data D _N of the data number N is read from the RAM13 into the register. In step S3, the current date T ₀ and the latest usage date T
The difference from _NX is calculated and stored in the register as the difference period T _DIF (T _DIF = T ₀ −T _NX ).

Then, in step S4, the difference period T
It is determined whether _DIF is A ₀ or more for a predetermined period. If the difference period T _DIF is less than the predetermined period A ₀ , it means that the data has been used within the period of A ₀ dating back from the present, so the data D _N is not erased, and the process skips to step S9. To do.

However, when the difference period T _DIF is _equal to or longer than the predetermined period A ₀ , the predetermined period A ₀ has already passed since the latest use, and it is used even once within the period of A ₀ dating back from the present. It has not been done. At this time,
Proceed to step S5, and stores the usage count number U _NX data D _N of the data number N in the register is read out from the RAM 13.

Then, in step S6, the usage count U _NX is divided by the difference period T _DIF , and the division result is α _N.
Is stored in the register as (α _N = U _NX / T _DIF ).
In step S7, it is determined whether the division result α _N is less than or equal to the predetermined value β ₀ . When it exceeds the predetermined value β ₀ ,
It is data that has not been used within the period of A _{0 since} the present time, but since the data is used relatively frequently, the data D _N is not erased and the process skips to step S9. ..

However, when the division result α _N is equal to or smaller than the predetermined value β ₀ , it means that the data has not been used within the period of A ₀ , which is traced back from the present, and the data is rarely used. become. Such data will be erased assuming that it will not be used again. That is, the process proceeds to step S8, automatically erase the data D _N of the data number N from the RAM 13.

In step S9, it is determined whether or not the determination has been completed for all the data. If not, the process proceeds to step S10 and the data number N is incremented by +.
After incrementing by 1, the process returns to step S2 and the same process is performed on the next data. By repeating such processing, it has been never used within the predetermined period A ₀ , and the frequency of use before the predetermined period A ₀ is sufficiently low (U _NX / T _DIF ≦ β ₀ ). The created data is automatically deleted from the RAM 13.

When the above-mentioned judgments for all the data are completed, the process proceeds to the main routine.

Instead of performing the operation from step S1 when the main power source is turned on, the operation may be performed by selecting the unnecessary data erasing mode at the arbitrary point of time by the user.

A specific example will be described with reference to FIG.

Here, 6 months is set as the predetermined period A ₀ , that is, A ₀ = 180 days is set, and the predetermined value β ₀ is set.
It is assumed that β ₀ = 0.009 is set.

The data D ₁₀₀ was used most recently,
It is 365 days ago from the present. It has been used four times since it was first registered. T _DIF = 36
5 and U ₁₀₀ = 4. Therefore, α ₁₀₀ = 4
/365≈0.011, which is β ₀ = 0.00
Compared with No. 9, since α ₁₀₀ > β ₀ , the data D _{10 0}
Remains registered and saved in the RAM 13.

Data D ₂₀₀ was also used most recently.
It is 365 days ago from the present. It has been used twice since it was first registered. T _DIF = 36
5 and U ₂₀₀ = 2. Therefore, α ₁₀₀ = 2
/365≈0.005, which is β ₀ = 0.00
Compared with _No. 9, since α ₂₀₀ <β ₀ , the data D _{20 0}
Will be erased from RAM 13.

The most recently used data D ₃₀₀ is
It is 200 days ago from the present. It has been used twice since it was first registered. T _DIF = 20
0 and U ₃₀₀ = 2. Therefore, α ₃₀₀ = 2
/200=0.010, which is β ₀ = 0.00
Compared to 9, because it is alpha _300> beta _0, data D _{30 0}
Remains registered and saved in the RAM 13.

The data D ₄₀₀ was used (displayed) most recently 200 days before the present date. And, it has never been used since it was first registered.
T _{DI F} = 200 and U ₄₀₀ = 0. Therefore, α ₄₀₀ = 0/200 = 0.000, which is
Compared with β ₀ = 0.009, since α ₄₀₀ <β ₀ , the data D ₄₀₀ is erased from the RAM 13.

The difference period T _DIF may be calculated in units of year, month, day, or in units of year, month, day, hour, etc.

By the way, in a data storage device having a memory capable of storing a large number of data (address book, telephone number, etc.), a memory reset switch for so-called one-shot erasing is provided. The memory reset switch is first operated before the shipment after the test in the production stage is completed, but it may be actively operated depending on the intention of the user.

As a cause of erasing all the stored contents of the memory, in addition to the operation of the memory reset switch,
This may be due to the disappearance of the backup when the battery is replaced, or due to static electricity, noise, or hardware failure such as detachment of the memory lead. Also, if the user mistakenly operates the memory reset switch, all the stored contents are naturally erased.

Therefore, it is necessary to presume the cause of all erasure of stored contents. As a countermeasure, it is possible to store the date and time when the memory reset operation is performed. This measure will be described with reference to FIG.

In FIG. 5, 21 is a CPU and 22 is a RO.
M, 23 is RAM, 24 is a backup power supply, 25 is a key input device, 26 is a display device, 27 is a gate array, 2
Reference numeral 8 is a real time clock, and 29 is a memory reset switch.

Now, it is assumed that some data is registered in the RAM 23. The operation for completely erasing the stored contents of the RAM 23 from this state will be described.

First, the memory reset switch 29 is pushed and operated. The signal is sent to the CPU via the gate array 27.
Then, the CPU 21 ends the operation currently being executed. Then, the CPU 21 displays a message confirming deletion of all stored contents on the display device 26, and waits for key input.
When the memory erase key on the key input device 25 is pressed, the RAM 23 is all cleared and initialized, and date and time data at the time of all clear is read from the real time clock 28 through the gate array 27.
Write to 3. Next, the initial screen is displayed.

Now, when all the stored data are lost, the all-clear date and time stored in the RAM 23 is referred to when estimating the cause. When the all-clear date and time is in the production stage, when the backup power supply 14 is replaced, or when it is unexpected, it is not due to the user's carelessness or other operational error. It can be estimated that it is caused by an unexpected factor or a set defect. Alternatively, it can be presumed that the stored contents are completely erased due to static electricity or noise, or that the stored contents are completely erased due to a defect in hardware such as a connection failure of the external lead of the RAM 23. Then, appropriate measures such as repair can be taken.

On the other hand, when the all-clear date and time is relatively recent, not at the production stage or when the backup power supply 14 is replaced, it can be presumed that an operation error by the user is a factor for erasing all stored contents.

Although the real-time clock 28 is used for writing the date and time, other data may be used.
Although the RAM 23 (main storage device) is used as the destination for writing the date and time, a dedicated memory element or register may be used instead.

[0053]

As described above, according to the present invention, data that is not frequently used for the elapsed period is automatically deleted from the memory as unnecessary data, which is troublesome and time-consuming for the user. You can be freed from data erasing work. By erasing the unnecessary data, the area for storing new data is constantly secured, and the memory can be effectively used.

When resetting all data,
If it is configured to store the time information at the time of the reset operation in the memory, it will be useful for estimating whether or not the cause of the complete deletion of the stored contents is the user's operation error, with reference to the all-clear date and time. be able to.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment of a data erasing system in a data storage device according to the present invention.

FIG. 2 is a memory format in the data storage device of the embodiment.

FIG. 3 is a flowchart for explaining the operation of the embodiment.

FIG. 4 is an explanatory diagram of a specific operation example of the embodiment.

FIG. 5 is a block diagram showing an electrical configuration of a data storage device according to another embodiment.

FIG. 6 is a block diagram showing an electrical configuration of a conventional data storage device.

FIG. 7 is a memory format in a conventional data storage device.

[Explanation of symbols]

 11,21 CPU 12,22 ROM 13,23 RAM 14,24 Backup power supply 15,25 Key input device 16,26 Display device 17 Clock device 27 Gate array 28 Real time clock 29 Memory reset switch

Claims (2)

[Claims] 1. The number of times each data is used is counted up and stored for each of a plurality of data registered in a memory, and the date when each data is used most recently (latest use date) is stored. If the difference between the current date and the latest usage date is calculated for each data, and the period of the difference is equal to or longer than the predetermined period, the number of times the data is used is divided by the period of the difference, and the result of the division is calculated. A data erasing system in a data storage device, wherein the data is automatically erased from the memory when is less than a predetermined value. 2. A data erasing system in a data storage device, wherein at the time of a reset operation for erasing all the data registered in the memory, time information at the time of the reset operation is stored in the memory.