JPS63165986A - Data storage system - Google Patents

Abstract

PURPOSE:To optionally store and read variable length data by dividing the data by fixed length and adding storing position information on the succeeding divided data to all these divided data. CONSTITUTION:When data are stored in a data area 6, these data are converted into the form of words. If the data to be stored exceeds the word length, the data is divided down to the length that can be stored within the word. The word containing the data is also accompanied by data (BCC: block check character) which secures the data of the word, a block (CB: control block) which shows the characteristics and the propriety of the data in the word, and data (CN: chain number) which shows the existing position (storage position) of the word following the relevant word.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a data storage method for storing data in a data memory of an IC card, for example.

(Prior Art) Recently, an IC card containing a built-in IC chip having a nonvolatile data memory and a control element such as an 08 port has been developed as a new portable data storage medium. This type of IC card is designed to store, read, and erase data in a built-in data memory using an internal control element or an external device.

A conventional data storage method for storing data in a data memory in such an IC card will be described below. FIG. 7 shows the format of the data memory, which consists of a plurality of areas. In each area? ! It can memorize defeat data (a unit of data that has meaning on its own). Record numbers as storage information are determined in the order in which data is received from the outside and stored, and the data is continuous (the first data of the next data comes immediately after the RtA data). When additionally storing new data, as shown in ■ in Figure M8, add the 1 & Hiiragi data (from the end of Ia of data (3) in Figure 8) before adding. Contents of the data that have already been stored The operation of rewriting data (1) is shown as an example of changing data (1) to S in Figure 1F!8.

(2) When exchanging data to data having the same data length as already stored data, the data exchange is performed normally.

■When rewriting data with a data length that is better than the length of the already stored data, t! of the already stored data! Since it is impossible to write data without destroying the next data (2), the data is not rewritten and an error occurs.

■If you replace 1 with data that has a shorter data length than the length of the data that has already been stored, there will be no problem during abuse, but there will be a problem when reading the following data (2), so replacing data with 1 is not a problem. Does not execute and results in an error.

I will explain the problem when reading. Figure 9 shows the area where data (up to 3 &!) is stored before m conversion.

Information indicating the appearance of the data (L] to L3 in the figure)
We use this to search for data one after another. For example, when reading data (21f), first, the length information of data (1) is obtained by using the starting end S of data (1) as !S quasi, and 1 is read, and n1laP of data (1) is found.Data (1)
The terminal end P of is the starting end of data ('2J).

In this way, find the terminal P of data (1), and
Start reading. Since the data after data (1) is read by the above 111tIIl, unless the thing corresponding to P indicates the correct place C, the data placed after data (1) cannot be read. This corresponds to the operation result of ■ in the eighth factor.

In Figure 8, Figure 10 shows the case where the data (1) is pressed to data with a shorter data length than the already stored data (1).New data (1)' is written. In this case, the official data will not be affected, but there will be areas filled with undefined data, such as the shaded areas in the figure.

When you want to read data (21), the length information Ll' of data (1)' is taken as a reference from the start end S' of data (1)'.
Read and find nra of data (1)'. If all data is arranged correctly (data is arranged consecutively), (end of data) - (start of next data)
Met. Thinking in the same way as when it is a normal array,
When data 2 in the case of FIG. Data is also read, and in the end, data 2 cannot be read, resulting in an error.

In this way, when data ψ is converted to lI, an error will occur if the data does not have the same data length as the existing data. Also, the data must be linked to the next data (encounter□diteaishi)) Problems arise when data appears one after another. Furthermore, the inside of one data must be 11R, and if the inside is interrupted, the data loses its meaning and becomes unreadable. Furthermore, since the data must be continuous, even if there are many spatial parts, if they are scattered, data with a large data length cannot be written.

(Problems to be Solved by the Invention) The present invention has been made to solve the above-mentioned problems when rewriting already stored data to data having a data length different from the data length. To provide a data storage system which allows rewriting of already stored data to data having a data length different from the data length without any problem and also causes no trouble when reading data.

[Structure of the Invention] (Means for Solving the Problems) The present invention has the following features! ! A data storage method in which data is stored on a medium, in which the data is divided into fixed length pieces, and storage location information of subsequent divided data is added to each of the divided data, and this storage location information is added. The first divided data of each divided data is stored from one end of the storage medium, and the divided data that continues after the first divided data is stored from the other end of the storage medium, and one of the predetermined data At the time of exchange, the first divided data of the data is replaced with the first divided data of new data, and
The storage area of the divided data that continues therefrom is erased, and the divided data that continues from the first divided data of new data is stored in order from the empty area at the other end of the storage medium.

(Effect) As a result, the constraints that data must be continuous with the next data and that the inside of the data must be continuous are eliminated, and errors that previously occurred due to these constraints can be treated as errors and treated as errors. Therefore, operations such as storing and reading variable-length data can be performed normally. Further, by adding storage position information of subsequent divided data to all divided data constituting one unit of data, it is possible to easily search for data no matter where it exists.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 6 schematically shows the configuration of an IC card according to the present invention, which includes a control element (for example, a CPU) 1, a nonvolatile data memory 2 whose storage contents can be erased, a program memory 3, and a card reader (not shown).・Consists of a contact part 4 for obtaining electrical contact with the writer, and of these, the part within the broken line (control element 1, data memory 2, program memory 3) is composed of one IC chip, It is embedded within the card. The data memory 2 is composed of, for example, an EEPROM, and is used to store various data. The program memory 3 is composed of, for example, a mask ROM, and stores control programs for the control element 1 and the like.

Figure 5 shows the format of data memory 2.
It is divided into a directory area 5 for controlling each area and a plurality of data areas 6 for storing various data. Each data area 6 is divided into words with a fixed length (λ bytes), and each word is divided into words with a physical address of 1.2.3. ...A lead number is assigned. This word number is not stored anywhere.

The data storage method of the present invention in such a configuration will be explained in detail. When storing data in the data area 6, the data must be converted into word form. If the length of the data to be stored exceeds the length of a word, it is divided into pieces of length that fit within the word. In addition, a word does not simply contain data; as shown in Figure 4, there is data (BCC; block check character) that guarantees the data in the word, and blocks (blocks) that indicate the nature and validity of the data in the word. CB: control block), data representing the location (memory location) of the word that should follow the word (CN: chain block);
(number, word number is used) is also attached.

FIG. 4 shows a method for storing data having a data length longer than the word length. The data consists of data length information and storage data as shown. Words that are divided by the division standard value (multi-2 bytes) based on the word length (lambda bytes) are divided into two types of words as shown in FIG. These words are distinguished depending on whether or not the word contains data length information. The word with data length information in the data part is the first word, and the directory word (DW) is
), the following word is a follow word (FW: Fol
Low Word). Each word stores the next word number, so for example, the CN of A contains the word number of B. When viewed in conjunction with Figure 2, CN of DWl corresponding to A contains the word number (n>) stored in FWlt, which is the word containing the next data. FW+
CN of t contains the stored word number (n-1) of FWt2, which is the word containing the next data. Note that when the data is restored, FWt2 corresponding to C contains data at the end of R, that is, there is no next word to continue, so data indicating that it is the final word is entered.

These words are stored in the data area 6 in the order shown in FIG. DWl is placed in an empty word viewed from the beginning of the area, or in a word in which DWr of designated data is stored (the former indicates additional writing, and the latter indicates rewriting). FWt t , F to follow the stored D W 1
Wt 2 is stored by searching for an empty word from the bottom word of the area. At this time, in the order of the words stored in the DW, "What number of data is the DW in?"
It serves as a data indicator (record number).

That is, it is sufficient to store the DWs in the data in the order of record numbers from the beginning of the area. Since the DW number and record number can be determined from the word arrangement, the DW arrangement (order) cannot be changed. FIG. 1(a) shows an example in which data 1 to 3 are stored through the above operations.

The rewriting of variable length data, which is the greatest advantage of the present invention, will be described below with reference to FIG.

Assume that there is an area filled with words as shown in FIG. 1(a). The data of record number "1" in this area has now been erased. The result is shown in FIG. 1(b). The data of record number "1" are DWl and FWlt in FIG. 1(a).

It was FWt2, but after being erased, it became FWtt.

The place where FWt2 existed becomes a completely blank word,
Any data (data not affected by record number and DW/FW) can be newly stored. In contrast, the word where DWr was present is not a completely blank word. If FW is stored in a word where DW existed in the past, this method counts DW from the beginning of the area.
The order of the W's will be out of order, which means the record numbers will be out of order. Therefore, even if the DW is deleted, the previous DW
Either you must leave the information that the DW was stored, or you must secure a place where only the DW exists and then delete it. 1st
In Figure (b), it is indicated as "del•DWt J" to mean that DWs was previously stored.

Next, Figure 1 (C) shows the case where data with record number "1" is newly stored and the data length of the newly stored data is one word less than the data length of the previous data. . The new data DW is stored in the del・DWl part (indicated as NEW-DWl), and NEW
-FWt t is also R1 in the area! A blank word is searched from the i-tail and stored. In Fig. 1(b), FWlt, F'Ah
2 has been deleted, so in Figure 1(C), FWlt
NEW-FWxt is stored in the same location as . At this time,
There is a blank space of one word between NEW-FWt 1 and FW21, but if a new FW comes, it will be stored there, so there is no problem. Of course, there is no problem in the case of reading. For example, as shown in FIG. 1(d), DW+ (FWxl
) (record number "4") is stored, the blank between FWII and FW2s is filled with F.
W41 is stored.

Now, consider the case of reading. For example, read record number "2". Specifying the area in the state shown in FIG. 1(d) and specifying the record number "2" at the same time, and upon receiving successive commands, searches the area and searches for DW2 with the record number "2". To search, start by counting record numbers from the beginning of the area to the middle of the word. In this case, since the record number is "2", the second DW from the beginning is recognized as DW2. Since DW2 stores the word number of the next FW21 (word number -7 for FW21), FW2t can be recognized regardless of the arrangement of the FWs.

In this way, by storing data in words that are blank anyway, it is possible to easily rewrite variable length data, which has been impossible until now.

Conventionally, stored data is continuous, and data must also be continuous with other data, and once a connection is made between data (see Figure 9)
If a part unrelated to the data is created between the data (see Fig. 10), the boundary between the data cannot be recognized and the area will be destroyed. That point,
In the method of the present invention, data is divided from the beginning, and the arrangement of the divided words does not matter except for the DW, so there is no problem. For example, as shown in Figure 1(d), DW+(FWX 1
') (record number [2J)
When rewriting data into data that is divided into a size of W+ (FWx2), if there is a space of DW10 (FWX2) in the entire area, it can be rewritten sufficiently, and the rewritten result is shown in Figure 1 ( Shown in e).

In addition, Fig. 1(f) shows an example in which data of record numbers @ "2" and "3" is deleted in the state of Fig. 1(e), and Fig. 1(q) shows an example of erasing the data of record numbers @ "2" and "3" in the state of Fig. 1(f). Record 'a@[5
An example in which data of J is stored is shown.

In this way, each divided area of the data memory is divided into words with a fixed length, and the data to be stored is also divided into the above fixed length, and each divided data is used to store the subsequent divided data. A word number @ (chain number) indicating the position is added, and the first divided data of each divided data to which this word number is added is stored from the first word of the area, and the divided data that continues after the first divided data is stored. Store from the RH word of the area. Then, when rewriting predetermined data, the first divided data of the data is rewritten to the first divided data of new data, and the words of the divided data that follow it are erased,
The divided data continuing from the first divided data of the new data are sequentially stored by searching for empty words from the last word of the area.

According to this data storage method, there is a conventional problem that data must be continuous with the next data.
11) Eliminates the constraint that the internal data must be continuous, and due to these constraints, errors that conventionally occur are no longer treated as errors, and operations such as storing and reading variable-length data can be performed normally. . In addition, by adding storage location information (word numbers) of subsequent divided data to all divided data that makes up one unit of data, it is possible to easily search for data no matter where it exists, and access time is reduced. becomes significantly faster.

In the above embodiment, the case where data is stored in the data memory built into the IC card has been described, but the present invention is not limited to this, and data may be stored in other storage media. The same applies to cases where

[Effects of the Invention] As described in detail above, according to the present invention, when data that has already been stored is rewritten to data having a data length different from the data length, it can be rewritten without any problem, and there is no problem when data is continuously rewritten. It can provide a data storage method that does not exist before.

[Brief explanation of the drawing]

1 to 6 are for explaining one embodiment of the present invention, and FIG. 1 is a diagram showing an example of data storage in an area;
Figure 2 is a diagram explaining the storage order of words, Figure 3 is a diagram explaining the meaning of words, Figure 4 is a diagram showing how data is divided into fixed lengths and converted into words, and Figure 5 is a diagram explaining the data FIG. 6 is a block diagram schematically showing the structure of an IC card. FIGS. 7 to 10 are for explaining conventional data storage systems. FIG. FIG. 8 is a diagram showing an example of a memory format, FIG. 8 is a diagram showing an example of data storage, FIG. 9 is a diagram showing an example of the existence of normal data, and FIG. 10 is a diagram showing an example of the existence of abnormal data. DESCRIPTION OF SYMBOLS 1...Control element, 2...Data memory (storage medium), 3...Program memory, 5.
...Directory area, 6...Data area. Applicant's Representative Patent Attorney Takehiko Suzue Figure 2 Figure 3 Figure 4 Figure 6 Figure 7 Figure 5 p Figure 9 Figure 10

Claims (2)

[Claims] (1) A data storage method in which data is stored in a storage medium, in which the data is divided into fixed-length pieces, and storage location information of subsequent divided data is added to each piece of divided data. The first divided data of each divided data to which position information has been added is stored from one end of the storage medium, and the divided data that continues after the first divided data is stored from the other end of the storage medium, and When rewriting data, the first divided data of the relevant data is rewritten to the first divided data of new data, the storage area of the subsequent divided data is erased, and the new data continues with the first divided data. 1. A data storage system characterized in that data of different data lengths can be rewritten by sequentially storing divided data starting from an empty area at the other end of the storage medium. (2) The data storage system according to claim 1, wherein the storage medium is a data memory provided in an IC card.