JP2661131B2 - Information storage and reading method and apparatus - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information storage / readout method and an apparatus for increasing the number of uses of a memory such as an EEPROM, which has a limited number of writes.

[Summary of the Invention] The present invention relates to an information storage / reading method and apparatus for a storage carrier having a limited number of times of writing, wherein the storage carrier is provided with a plurality of data areas and a plurality of use order areas corresponding thereto, and the data area is provided in the data area. Each time writing is performed, the use order of the corresponding use order area is rewritten, and the plurality of data areas are used in order according to the use order. The number of times of use is increased.

[Prior art] Conventionally, for backup of data when power is turned off,
EEPROM as electrically rewritable nonvolatile storage carrier
(Electrically erasable programmable read only memory) and the like are used.

[Problems to be Solved by the Invention] However, the storage carrier such as the EEPROM in the above-mentioned conventional technology has a problem that the number of times of writing is limited. In other words, the EEPR guaranteed by the manufacturer
If the number of times the OM is written is small, it may be unsuitable for use in backing up data when the power is turned off. For example, in the case of guarantee of 10,000 times, if writing 10 times a day, there is a possibility that it will not be able to be used in 3 years, and if writing 30 times a day, it will be 1 year. There is a possibility that it cannot be used. As described above, the use of the EEPROM or the like with a small number of guaranteed write operations is limited.

The present invention has been made in order to solve the above-mentioned problems, and an information storage / reading method and an information storage / reading method capable of increasing the number of times of use of writing on a storage carrier such as an EEPROM or more, beyond the limit of the number of times of writing. It is intended to provide a device.

[Means for Solving the Problems] To achieve the above object, an information storage and reading method according to the present invention is an information storage and reading method for a storage carrier having a limited number of times of writing. A data area and a plurality of use order areas corresponding to the data area are provided, and information indicating a use order is sequentially written into each use order area using a monotonically increasing number sequence or a monotonically decreasing number sequence, and data is written into the data area. The head order is determined from the monotone increasing sequence or the monotone decreasing sequence in the information read from the plurality of use order areas, and data is written to the data area corresponding to the use order area of the start order, and only the start order is written. To the value following the monotone increasing sequence or the monotone decreasing sequence, and when reading the written data, Determining a final rank from the monotone increasing sequence or the monotone decreasing sequence in the information read from the plurality of use order areas, and reading data of a data area corresponding to the use order area of the final order, The configuration of the information storage and reading device of the present invention includes a storage carrier having a limited number of times of writing, the storage carrier is provided with a plurality of data areas and a plurality of use order areas corresponding thereto, and each use order is first set. The information indicating the use order is sequentially written into the area using the monotonically increasing number sequence or the monotonically decreasing number sequence, and data is written to the data area corresponding to the use order area of the top order determined from the monotonically increasing number sequence or the monotonically decreasing number sequence. Only the top rank of the use rank area is written in the final rank using the value following the monotone increasing sequence or the monotone decreasing sequence. Ete,
A control means for sequentially using the plurality of data areas is provided.

[Operation] In the present invention, a plurality of (n) data areas are provided on a storage carrier having a limit of the number of writing times (m times), so that the data area is provided with n times redundancy, and the same storage carrier is used. The use order is written in the use order area provided corresponding to each data area, and the use order is rewritten to the final order every time data is written in the corresponding data area.
When writing new data, n data areas are used in order by always using the data area corresponding to the leading order. This makes it possible to use the storage medium for writing m × n times. That is, the number of uses of the storage carrier is set to n times the limit of the number of times of writing.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the information storage / readout device of the present invention. In this embodiment, an example is described in which 1-byte data is written up to m × n times in an EEPROM that is guaranteed to be written m times. In this embodiment, the data writing EEPROM 1 is used.
And a pointer EEPROM 2 and a control unit 3. The data write EEPROM 1 has a capacity to provide at least 1-byte data area of n bytes.
EE for pointers with at least n bytes capacity
The PROM 2 is provided with n bytes of a 1-byte pointer area for storing information indicating the use order of each data area corresponding to each of the above-mentioned data areas.

The control unit 3 includes a processor 31, a ROM 33 and a RAM 34 connected to a bus 32 of the processor 31, a write circuit 35, a read circuit 36, and the like. The writing circuit 35 is a processor
The data area of EEPROM1 specified for initialization processing at power-on and data retention at power-off by 31 and the EEPROM2 for pointer corresponding to the data area
Has the function of writing to the pointer area of The read circuit 36 has a function of reading the pointer area and the data area also designated by the processor 31. The processor 31 instructs the writing of the use order in the pointer area of the pointer EEPROM 2 in the initialization process, reads out the use order through the readout circuit 36 to retain the data at the time of power-off, and determines the head order. The data is written via the write circuit 35 to the data area corresponding to the pointer area that holds.
Before or after this time, the processor 31 rewrites the top rank of the pointer area to the last rank. After power-on, if you want to use the latest data stored above,
U31 reads the use order of the pointer EEPROM 2 via the read circuit 36 to determine the final order, and reads out the data in the data area corresponding to the pointer area holding the final order via the read circuit 36. The procedure of the above processing and determination is stored in the ROM 33, and the use order and data read from the EEPROMs 1 and 2 are transferred to the RAM 34 and used for processing and determination.

An embodiment of the information storage / readout method of the present invention in the embodiment configured as described above will be described. FIG. 2 is a flowchart showing one embodiment. The processing is started by power-on, and first, information on the use order of n bytes of the pointer area is read. Here, the initial state of the EEPROM is determined based on whether or not the use order (for example, 0 to n-1) has already been written. If the initial state, the initialization of the pointer area, that is, the use order (0 To n-1) are written. If the use order has already been written, the final order is determined from the read use orders, data is read from the data area corresponding to the pointer area, and transferred to, for example, RAM, and used for general processing. . The above is the reading process. Subsequently, when the latest data to be held at the time of power-off occurs, the top rank of the use rank read out above is determined, and for example, n is added to the top rank of the pointer area to make the final rank, and then the pointer rank is determined. The latest data is written to the data area corresponding to the area to prepare for the next power-off. In this way, the n data areas can be sequentially used for writing, and the latest data is stored in the data area corresponding to the pointer area holding the final rank, so that the data is retained even when the power is turned off. The final ranking to be performed is a mark, and is specified when the power is turned on.

Next, how to identify the used data area based on the use order information of the pointer area will be described. FIGS. 3 and 4 are diagrams for explaining the use of the pointer area, and show the change in the use order of the pointer area every time data is written. In FIG. 3, (a) is an initial state, (b)
,..., (X) indicate the order in which data writing changes. Here, the description will be made assuming that the number n of the data areas is n = 10. EEPROM
Is the state before initialization (perhaps all are hexadecimal and FF
Or 00) can be easily determined based on whether or not the contents of the read pointer EEPROM are arranged in order. In this case, as shown in (a), for example, 00, 01, 02,..., 09 (= n−
Write the number of 1) in order from the 1st byte to the 10th byte. In (a), 00 indicates the top rank and 09 indicates the last rank. That is, the maximum value indicates the final rank, and the minimum value indicates the head position of the next use. As shown in (b), the first data write uses a data area corresponding to the pointer area in which 00 is written. For the purpose of use, + n (= 10 ) As 0A (hexadecimal notation, same hereafter). As a result, the use order of the used data area always becomes the maximum value, indicating the final order, and serves as a mark indicating that the latest data has been written therein. Data writing is performed based on the order of use of the minimum value, the first byte → the second byte → the third byte →... → the nth byte → 1
It is performed in the order of the byte →. Therefore for pointers for landmarks
The contents of the EEPROM are shown in (b) → (c) → (d) → of FIG.
→ It changes like (x). As described above, when + n is continued for a mark for each use, a case where 00 is included in the use order and the use order is 00 (0 cross) occurs as shown in FIG. 4 (X). In this case, FX (X = 1,2,
…, F) is ignored, and the maximum value of only 0 or more is obtained as a mark indicating the latest data (final rank). On the other hand, the value of 0 or more is ignored, the minimum value is obtained in FX, and then writing is performed. In this case, it is the first rank. At this time, the pointer area next to the last rank may be determined as the top rank.

In the above embodiment, the data area is 1 byte. However, in general, one data area may be composed of a plurality of bytes or an arbitrary number of bits as one word, and the present invention is limited to the EEPROM. Instead, the present invention can be applied to a storage carrier having a limited number of writings. Further, in general, not only various monotonically increasing sequences but also monotonically decreasing sequences can be used as the sequences indicating the use order.
Therefore, the method of the above embodiment can be generally expressed as follows.

(1) In a method of storing and reading information (data) in n words of a main (data writing) storage carrier having an arbitrary number of bits per word, a mark having a bit number of (log ₂ n) +1 bits or more ( A sequence of monotonically increasing or monotonically decreasing numbers is sequentially written into n words of a memory carrier for a pointer.

(2) When writing information to the main storage carrier, a value exceeding the maximum value of the monotonically increasing number sequence or a position exceeding the maximum value of the monotonically increasing sequence at the position of the mark storage carrier (leading position) corresponding to the writing position of the main storage carrier. Write a value less than the minimum value in the monotonically decreasing sequence. Here, the writing position is the position of the minimum value in the case of the monotonically increasing sequence, and the maximum value position in the case of the monotonically decreasing sequence.

(3) When the value written to the marker storage carrier is out of a predetermined range of 2n or more types, the data is repeatedly written from the initial value of the sequence.

(4) When reading out information, read out all the information (use order) of the above-mentioned marker storage carrier, and if a monotonically increasing sequence is written in advance, the position where the maximum value is stored is determined in advance by monotone. When the decreasing number sequence is written, the reading determination is performed such that the position where the minimum value is stored is the read determination position (latest data position = final rank). At this time, if there is a detection value (for example, in the case of 0 cross) in which the predetermined rise or fall detection is present in the read information (use order) from the mark storage carrier, the read information in the read information is used. Invalidate the read information having the value before going up or down,
The reading is determined from information other than the invalidated reading information.

(5) The information of the main storage carrier at the position determined by the read determination is read.

In the above-described embodiment, the EEPROM for pointer and the EEPROM for data writing are separate, but one EEPROM is used.
It is also possible to provide a data area and a pointer area in the OM.

As described above, the present invention can be applied variously according to the gist and can take various embodiments.

[Effects of the Invention] As is clear from the above description, the information storage / readout method and apparatus according to the present invention have the following effects.

(1) The number of write operations of a storage medium having a limited number of write operations can be increased n times by providing n data areas and pointer areas.

(2) Even a storage medium with a small number of write operations can be used when a large number of write operations are required, such as data backup at power-off. That is, it is possible to expand the use of the storage carrier with a small number of writings.

(3) Since data is not continuously written in the same data area, damage to a storage carrier such as an EEPROM is reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the information storage / readout apparatus of the present invention, FIG. 2 is a flowchart showing an embodiment of the information storage / readout method of the present invention, and FIGS. FIG. 1 ... EEPROM for writing data, 2 ... EE for pointer
PROM, 3... Control unit (control means).

 ────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-61-158090 (JP, A) JP-A-61-150195 (JP, A) JP-A-61-151897 (JP, A)

Claims (2)

(57) [Claims] An information storage and reading method for a storage medium having a limited number of times of writing, wherein said storage medium is provided with a plurality of data areas and a plurality of use order areas corresponding to the data areas. Information indicating the use order is sequentially written using a monotonically increasing sequence or a monotonically decreasing sequence, and when writing data to the data area, the leading order from the monotonically increasing sequence or the monotonically decreasing sequence in the information read from the plurality of use order areas. And writing data to the data area corresponding to the use order area of the leading order, and rewriting only the leading order to a value following the monotone increasing sequence or the monotone decreasing sequence, and reading the written data. Whether a monotonically increasing sequence or a monotonically decreasing sequence in the information read from the plurality of use order areas An information storing and reading method, wherein a final rank is determined from the data, and data in a data area corresponding to the use rank area of the final rank is read. 2. A storage medium having a limited number of times of writing, comprising a plurality of data areas and a plurality of use order areas corresponding to the plurality of data areas. Alternatively, information indicating the use order is written using the monotone decreasing sequence, and each time data is written to the data area corresponding to the use order area of the leading order determined from the monotonically increasing sequence or the monotone decreasing sequence, the use order area is written. An information reading apparatus, comprising: a control unit that rewrites only a leading order to a final order using a value following the monotone increasing sequence or the monotone decreasing sequence and uses the plurality of data areas in order.