JP5100500B2 - Data rewriting system, new edition data creation device, difference data creation device, new edition data creation program, and difference data creation program - Google Patents

Description

  The present invention relates to software rewriting intended for small embedded devices such as mobile phones.

  One of the information processing storage devices is a flash memory device, which is used in a built-in device such as a mobile phone. This flash memory is generally classified into a NAND flash memory and a NOR flash memory. The NOR type flash memory has a technique called XIP (eXecut In Place), which can be accessed randomly and the code can be executed as it is. On the other hand, in the NAND flash memory, the code on the memory must be loaded onto the RAM and executed. However, the NAND flash memory is generally cheaper if the capacity is the same.

  In the case of a NAND flash memory, since code is loaded onto the RAM, data may be compressed on the memory. This is because, depending on the reduction in memory usage and the processing speed, there are cases where the smaller the amount of data read from the flash memory, the higher the speed of development. In that case, a compression algorithm with a high expansion speed is employed.

  In software update, the difference data generally tends to be larger when the compressed images are compared than the difference between the original images. For this reason, a method of expanding the differential data once and compressing it again becomes common. In this case, the problem is that compression takes time.

  Japanese Patent Application Laid-Open No. 2007-293461 discloses a method of increasing the compression rate of program code and developing it at high speed. However, the point of high speed compression on a poor CPU (Central Processing Unit) device is disclosed. There is no suggestion.

  Japanese Patent Application Laid-Open No. 2000-516058 also discloses a technical disclosure relating to the improvement of compression efficiency, but it is necessary to read the memory many times in order to improve the efficiency, and there is no disclosure or suggestion regarding the increase in speed.

As described above, conventionally, the technology has been developed with an emphasis on the efficiency of compression and the speed of expansion. This is because there are few cases where the scale of embedded software is large and problems occur as in the present, there are not many devices using NAND flash memory, and the number of devices that are on the market like mobile phones This is because there were few things with large scale.
JP 2007-293461 A JP 2000-516058 A

  An object of the present invention is to compress a program at high speed on an embedded device having a low processing capability with respect to software update.

The data rewriting system of this invention is
A difference data creation device for creating difference data indicating the change contents of the new version data which is the data after the change of the old version data with respect to the old version data which is the data before the change;
Applying the difference data created by the difference data creation device to the old version data, rewriting the old version data to create the new version data, and a new version data creation device using the created new version data; In the prepared data rewriting system,
The difference data creation device includes:
A difference data creation unit for creating the difference data from the new version data and the old version data;
A compression rule information creation unit that compresses the new version data and creates compression rule information indicating a compression rule of the new version data when the new version data is compressed,
The new edition data creation device
A compressed data storage unit for storing the compressed old version data;
A difference data input unit to which the difference data created by the difference data creation device and the compression rule information are input;
A decompression unit that reads and decompresses the compressed previous version data stored in the compressed data storage unit;
A difference application unit that creates the new version data by applying the difference data input to the difference data input unit to the old version data expanded by the expansion unit;
A compression unit that compresses the new version data created by the difference application unit based on the compression rule information input to the difference data input unit, and stores the compressed new version data in the compressed data storage unit; It is characterized by having.

  According to the present invention, a program can be compressed at high speed on an embedded device having a low processing capability with respect to software update.

Embodiment 1 FIG.
The first embodiment will be described with reference to FIGS.

(Hardware configuration)
FIG. 1 is a diagram illustrating hardware resources of the PC 1000 or the embedded device 2000 in the development environment according to the first embodiment. The PC 1000 and the embedded device 2000 in the development environment are both computers. Since the development environment PC 1000 and the embedded device 2000 have the same hardware resources, the description of FIG. 1 assumes the development environment PC 1000, but the description of the development environment PC 1000 also applies to the embedded device 2000 as it is.

  In FIG. 1, a development environment PC 1000 includes a CPU 810 (Central Processing Unit) that executes a program. The CPU 810 is connected to a ROM (Read Only Memory) 811, a RAM (Random Access Memory) 812, a display device 813 such as a liquid crystal display, an operation key 814, a communication board 816, and a magnetic disk device 820 via a bus 825. Control hardware devices. A storage device such as a flash memory may be used instead of the magnetic disk device 820. As will be described later, it is assumed that the embedded device 2000 includes a NAND flash memory.

  The RAM 812 is an example of a volatile memory. Storage media such as the ROM 811 and the magnetic disk device 820 are examples of nonvolatile memories. These are examples of a storage device, a storage unit, or a storage unit. The communication board 816, the operation keys 814, and the like are examples of an input unit and an input device. The communication board 816 and the display device 813 are examples of an output unit and an output device.

  The communication board 816 is connected to a network and can communicate with the embedded device 2000 via the network.

  The magnetic disk device 820 stores an operating system 821 (OS), a window system 822, a program group 823, and a file group 824. The programs in the program group 823 are executed by the CPU 810 and the operating system 821.

  The program group 823 stores a program that executes a function described as “˜unit” in the description of the embodiment described below. The program is read and executed by the CPU 810.

  The file group 824 includes “determination result”, “calculation result”, “extraction result”, “generation result”, and “processing result” in the description of the embodiment described below. Information, data, signal values, variable values, parameters, and the like are stored as items of “˜file” and “˜database”. The “˜file” and “˜database” are stored in a recording medium such as a disk or a memory. Information, data, signal values, variable values, and parameters stored in a storage medium such as a disk or memory are read out to the main memory or cache memory by the CPU 810 via a read / write circuit, and extracted, searched, referenced, compared, and calculated. • Used for CPU operations such as calculation, processing, output, and display. Information, data, signal values, variable values, and parameters are temporarily stored in the main memory, cache memory, and buffer memory during the CPU operation of extraction, search, reference, comparison, calculation, calculation, processing, output, and display. Is done.

  Further, in the description of the embodiment described below, what is described as “to part” may be “to means”, “to apparatus”, “to circuit”, and “to device”. It may be “˜step”, “˜procedure”, “˜processing”. That is, what is described as “˜unit” may be realized by firmware stored in the ROM 811. Alternatively, it may be implemented only by software, or only by hardware such as elements, devices, substrates, and wirings, by a combination of software and hardware, or by a combination of firmware. The program is read by the CPU 810 and executed by the CPU 810. That is, the program causes the computer to function as “to part” described below.

  FIG. 2 is a diagram showing a general software update system of the embedded device 22.

  The PC 11 is a PC (Personal Computer) of a development environment for creating a software image of the target embedded device 22. The data transfer unit 160 is a module that transfers data from the PC 11 to the embedded device 22. The data transfer unit 160 may be, for example, a USB cable or a wireless network such as a mobile phone network.

  On the development environment PC 11, there are an old version program 151 (binary image of the old version program) and a new version program 152 (binary image of the old version program). The difference extraction unit 110 extracts the difference between the two and generates difference data 153. The PC 11 transfers the difference data 153 to the embedded device 22 using the data transfer unit 160.

  The embedded device 22 includes a NAND flash memory 260 (also called a NAND flash ROM), a program group 280 on the NAND flash memory 260, and a RAM 210 for executing the program. The execution program 281 is an execution program on the RAM 210. The execution program 281 is read out from the program group 280 of the NAND flash memory 260 and expanded by the data expansion unit 135. On the RAM 210, the difference data 153 transferred by the data transfer unit 160 is applied to the execution program 281 to create a new version program, and the embedded version compression unit 250 compresses the new version program and stores it on the NAND flash memory 260. Save a new one.

  When the compressed data is stored in a compressed form on the NAND flash memory 260, the data expansion unit 230 decompresses and decompresses the data from the compressed state. On the other hand, when the data is stored in the NAND flash memory 260, the embedded compression unit 250 Compress and save.

  Next, the configuration of the PC 1000, which is the development environment PC according to the first embodiment, will be described with reference to FIG. The PC 1000 is a development environment PC similar to the development environment PC 11 in FIG. 3 shows the old version program 151, the new version program 152, the difference extraction unit 110 (difference data creation unit), and the output difference data 153, as in FIG. In addition, the configuration includes a compression processing unit 120 (compression rule information creation unit) composed of a PC side compression unit 121 and a compression information generation unit 122, and a compression processing data transmission unit 130 (compression rule information transmission unit). is there. The target for creating a new version from the difference is not limited to the program, and may be general data including the program.

  The PC side compression unit 121 compresses the binary file using, for example, a byte pair compression algorithm. The post-compression data 154 of the new version program obtained as a result of the compression consists of compression state information (compression rule information) and compressed data used when decompressing. The compression state information is also used when the embedded device 2000 compresses the new version program, as will be described later. The compression state information (compression rule information) is information indicating a compression rule for new edition data.

  The compression information generation unit 122 extracts only the compression state information 155 from the post-compression data 154 compressed by the PC side compression unit 121, and outputs the compression state information 155.

  Next, the operation of the PC 1000 in FIG. 3 will be described using the example of data shown in FIGS. FIG. 5 shows new version data 401, old version data 402, and difference data 403 between the new version data 401 and the old version data 402. FIG. 6 shows an example of data compression by the PC side compression unit 121.

First, the difference extraction unit 110 executes the following processing according to the flow of FIG.
(1) In step 301, the difference extraction unit 110 reads the new version data 401 into a memory (not shown).
(2) In step 302, the difference extraction unit 110 reads the old version data 402 into the memory.
(3) In step 303, the difference extraction unit 110 performs binary difference extraction. The difference is expressed in the form of, for example, the same part, a changed part, and a moved part.

  In the case of the new version data 401 and the old version data 402 illustrated in FIG. 5, the difference data becomes the difference data 403. Actually, since the original data for obtaining the difference is 16-byte data, the data size is smaller than sending the new edition data by expressing the difference by the difference. This is because the difference data 403 uses commands such as “SKIP” and “COPY”, and therefore the data size is reduced.

  In step 304, the PC side compression unit 121 compresses the new version data 401. Here, as an example of the compression algorithm, a case will be described in which byte pair compression, which is an algorithm capable of high-speed expansion, is used (FIG. 6). Note that the compression method used is not limited to the byte pair compression method, and other compression algorithms such as LZH and ZIP may be used. Even when these algorithms are used, compressed state information is generated.

(Byte pair compression)
The byte pair compression algorithm is described in, for example, literature (Information Processing Society of Japan Research Report SLDM, Vol. 2001, No, 42 (20010517) pp. 1-6). In this compression method, as shown in FIG. 6, the new edition data 401 is compressed by repeating the compression operation in stages. In the example of FIG. 6, the new version data 401 is not compressed as a whole, but the new version data 401 is divided into new version data (401-1) and new version data (401-2), and each is compressed individually. An example is shown. FIG. 6 shows compressed data (501-1) and corresponding compression state information (502-1), and compressed data (501-2) and corresponding compression state information (502-2). ing. The compression state information (502-1) and the compression state information (502-2) are called a compression dictionary. In addition, when compressing, it may be divided and compressed as shown in FIG. 6, or the whole may be compressed together. Not only the case of compressing but also the case of extracting a difference may be divided and outputted.

  In step 305, the compression information generation unit 122 extracts only the compression state information. If this is described with reference to the example shown in FIG. 6, the compression information generation unit 122 extracts the compression state information (502-1) and the compression state information (502-2).

  Thus, the operation of the PC 1000 on the development environment is completed, and the difference data of the new version data with respect to the old version data and the compression state information are completed.

  If the size of the difference data obtained as a result of the difference extraction in step 303 is larger than the total size of the compressed data of the new version data and the compression state information, the new version data is output as the difference data as it is, and the embedded device 2000 However, the flag information that understands that is output together. The embedded device 2000 acquires the new edition data as it is as the difference data. In this case, the embedded device 2000 acquires the compression state information of the new version data and the flag information together with the new version data. In the embedded device 2000, the embedded compression unit 250 refers to the acquired compression state information according to the flag and compresses the acquired new version data without applying the difference, and the NAND flash memory together with the compression state information. And the compression state information 271 and the compressed data 272 are updated.

(Embedded device 2000)
Next, FIG. 7 shows a configuration of an embedded device 2000 that is a target of software update. FIG. 7 shows the overall configuration of the embedded device 2000. An execution program 270 is arranged in the NAND flash memory 260 (compressed data storage unit). The execution program 270 is in a compressed form. The execution program 270 includes compression state information 271 and compressed data 272 used when the data expansion unit 230 decompresses the compression. The data decompression unit 230 decompresses the compressed data 272 while looking at the compression state information 271 to decompress the compressed data 272 at a high speed to form the old decompressed data 211.

  Next, the difference data 213 and the compression state information 214 are transferred by the compression processing data transmission unit 130 to the difference data 153 and the compression state information 155 shown in FIG. 3 via the data transfer unit 160 shown in FIG. It is arranged on the RAM 210. The compressed state information 214 may be temporarily stored in the NAND flash memory 260 after being placed on the RAM 210.

  The difference application unit 240 applies the difference data 213 on the RAM 210 to the old development data 211 to generate new development data 212. The new development data 212 is the same as the new version program (new version data) in the PC 1000 in the development environment. In this way, the same application as the new version program 152 on the PC environment is created by the difference application unit 240. Then, the embedded compression unit 250 compresses the new decompressed data 212 and stores it in the NAND flash memory 260, thereby newly updating the compressed state information 271 and the compressed data 272. That is, in FIG. 7, the compressed state information 271 in the NAND flash memory 260 is updated to the compressed state information 214, and the compressed data 272 is updated to the compressed new decompressed data 212. A feature of the embedded device 2000 is that the embedded compression unit 250 compresses the newly developed data 212 at high speed using the compression state information 214.

  Next, the flow of processing in the embedded device 2000 will be described using the flow of FIG. 8 and the example of the data of FIG.

  First, in step 701, the data expansion unit 230 expands the compressed data 272 corresponding to the old version program in the compressed state on the NAND flash memory 260 while viewing the compressed state information 271.

  FIG. 9 shows a specific example. In the old compressed state 801, “XWWZ” and “ZWWX” correspond to the compressed data 272. “(W = XE, X = YD, Y = ZC, Z = AB)” is the compression state information of “XWWZ”, and “(W = XE, X = YZ, Y = AB, Z = CD)” is This is the compression state information of “ZWWX”. The old version data 802 is obtained by expanding the compressed version 801 of the old version. The old version data 802 corresponds to the old expanded data 211 (that is, the old version program).

  In step 702, the difference application unit 240 reads the difference data 213. Specifically, for example, the difference data 403 illustrated in FIG. 5 is transferred and stored as the difference data 213.

  In step 703, the difference application unit 240 applies the difference data 213 to the old development data 211 (old version program), and creates new development data 212 (new version program). As a result, the new development data 212 on the RAM 210 is exactly the same as the new version program 152 of the PC 1000. As a specific example, if the new version data created by the difference application unit 240 is the new version data 901 in FIG. 10, this is the same as the new version data 401 in FIG. 5 shown as a specific example of the new version data in FIG. It becomes.

  In step 704, the embedded compression unit 250 uses the compression state information 214 (compressed state information 902 corresponding to the new version data 901) when compressing the new decompressed data 212 (for example, the new version data 901). To do. As a result, the embedded compression unit 250 does not require analysis processing such as regularity of character appearance for compressing the new version data, and can compress the new version data at high speed.

  In step 705, the embedded compression unit 250 stores the compressed new version data and the compression state information 214 used for the compression in the NAND flash memory 260, and updates the compression state information 271 and the compression state information 271.

  Next, a normal compression flow (compression flow when compression state information is not used) will be described with reference to FIG. 11 using the example of compressed data in FIG. 6, and compression using compression state information will be described with reference to FIG. The flow of will be described.

  To compress when there is no compression state information, in step 901, the whole is first searched to find the most numerous 2 byte pairs. In the example of FIG. 6, AB is the largest. In step 902, this is replaced with an unused one-byte code Z.

  Since Z exists in step 903 and the whole becomes shorter if replaced in step 904, the replacement is actually performed in step 905, and the process is repeated to the next step 901. The compression is performed by repeating this as shown in FIG. In the example of FIG. 6, since the whole is divided into two and compressed, this whole process is repeated twice. In this example, as a result, the whole is read five times.

Next, the flow in the case of using the compression state information is shown in FIG. 12, and the operation will be described with reference to the example of FIG.

  In step 1001, the built-in compression unit 250 expands the compression state information. For example, assume that data (1101-1) and data (1101-2) shown in FIG. 13 are compression state information. In that case, the built-in compression unit 250 uses the codes (A, B, C, D, and V) that were originally used as unused one-byte codes (V, W, X, Y, and Z in FIG. 13). E, F) is replaced with a configuration. The result of the replacement is data 1102 (because data (1101-1) and data (1101-2) are the same).

  Next, in step 1002, the embedded compression unit 250 converts the expanded data (in this example, data 1102) into an index with each size. An example is data 1103 in FIG. This is intended to be used to determine whether the corresponding replacement is possible from the character string.

  In step 1003, the embedded compression unit 250 searches for the corresponding data from the beginning of the data 1104 to be compressed (same as the new version data 401) to the maximum length of the data 1103. In this case, since it is known that the maximum length is 6 bytes, it is judged by looking at 6 bytes from the beginning. In this example, since there is no corresponding ABCDBA, a 5-byte ABCDA is searched next. Since it is not also here, the next 4-byte ABCD is searched. In this case, ABCD can be replaced.

  For this reason, in step 1004, the built-in compression unit 250 replaces ABCD with X and repeats the same from the fifth byte.

  In step 1005, the built-in compression unit 250 determines whether it is the last.

  In this method, since the operation can be performed with one pass and an index or the like can be used for searching the dictionary, compression can be performed at high speed.

  By adopting such a method, it is possible to obtain an effect of being able to compress at high speed even on an embedded device having a low processing capability.

  In addition, in the NAND flash memory-based embedded device that uses the program code after being compressed from the viewpoint of cost and performance, it is possible to shorten the software update time and express the difference data small. Is possible.

Embodiment 2. FIG.
Next, the second embodiment will be described with reference to FIGS. Embodiment 2 describes an embodiment in which new version data created based on difference data is compressed based on a developed dictionary stored in the embedded device 2000 at the time of shipment.

  FIG. 14 is a configuration diagram of the development environment PC 1000 according to the second embodiment. The function of each component is the same as in the first embodiment. FIG. 15 is a diagram for explaining the expansion dictionary. FIG. 16 is a configuration diagram of the embedded device 2000 according to the second embodiment. The function of each component is the same as in the first embodiment. Normally, compression dictionary information (decompression dictionary) for high-speed decompression is stored on an embedded device such as a mobile phone. This is different from a dictionary for performing compression at high speed. In FIG. 15, the token is the same as the unused 1-byte code such as V, W, X, Y, Z described in FIG. For example, the token “00” may be regarded as “V”, and “02” as “W”. The first line of the expansion dictionary indicates that “00” is replaced with “50, 60”. The second line indicates that “02” is replaced with “00, FF”, that is, “00” is “50, 60”, and is thus replaced with “50, 60, FF”. In addition, “order information” (correction rule information) is shown on the left side. Here, the order information of the combination of the token and the pair is information necessary for compression into the same state. The expansion dictionary is often changed by sorting this order with tokens in order to perform expansion at high speed. That is, since the purpose of the compression dictionary for compression and the expansion dictionary for expansion are different, the holding method should be changed. For example, order information may be included in the difference data to return (correct) the sorted state to the original state (compression dictionary). As described above, the “order information” is information indicating a correction rule to be corrected to a compression dictionary used for compressing new edition data. In this case, since 1-byte order information is required for every 3 bytes of each token and pair, inheriting the dictionary does not send the dictionary, but instead replaces the 3 bytes in the dictionary with 1-byte Replace with order information and send. Therefore, the size of data to be transmitted is 1/3 compared to the case of transmitting a dictionary.

(Operation of environment development PC1000)
(1) The environment development PC 1000 creates difference data in the same manner as in the first embodiment when it becomes necessary to create difference data.
(2) When the difference data is generated, the compression information generation unit 122 acquires the compression dictionary of the old version data. For example, in order to store the compressed data (old version data) in the embedded device 2000 at the time of shipment, the PC side compression unit 121 compresses the old version data, and the compression information generation unit 122 extracts a compression dictionary from the post-compression data. The compression information generation unit 122 stores this compression dictionary in a storage unit (not shown). The compression information generation unit 122 acquires a compression dictionary of old version data from the storage unit. If there is no compression dictionary in the storage unit, the PC-side compression unit 121 compresses the old version data again.
(3) The compression information generation unit 122 creates the above-described order information based on the acquired compression dictionary.
(4) The compressed data transmission unit 130 transmits the difference data and the order information to the embedded device 2000.

(Operation of embedded device 2000)
(1) The NAND flash memory 260 stores compressed old version data and a development dictionary 271 used for decompressing the compressed old version data.
(2) The difference data input unit 220 receives the difference data and order information created by the development environment PC 1000 (difference data creation device).
(3) The data expansion unit 230 reads the compressed old version data stored in the NAND flash memory 260 and the expansion dictionary, and expands the compressed old version data using the expansion dictionary.
(4) The difference application unit 240 creates new version data by applying the difference data received by the difference data input unit 220 to the old version data expanded by the data expansion unit 230.
(5) The embedded compression unit modifies the expansion dictionary stored in the NAND flash memory 260 into a compression dictionary according to the order information received by the difference data input unit 220.
(6) Then, the new version data created by the difference application unit 240 is compressed using a compression dictionary modified from the expanded dictionary, and the compressed new version data is stored in the NAND flash memory 260.

Embodiment 3 FIG.
Next, Embodiment 3 will be described with reference to FIGS. The third embodiment is an embodiment in which transmission of the “dictionary order information” transmitted from the development environment PC 1000 to the embedded device 2000 in the second embodiment is unnecessary. The condition for this is that the compression dictionary data (compression dictionary) should be the same as the expansion dictionary data (expansion dictionary). Therefore, the following procedure is used for implementation.

(Storage of compression / decompression dictionary)
(1) Since the compressed data (old version data) is stored in the embedded device 2000 at the time of shipment, the PC side compression unit 121 compresses the old version data, and the compression information generation unit 122 extracts a compression dictionary from the post-compression data.
(2) The compression information generation unit 122 generates a decompression / compression combined dictionary from the extracted compression dictionary. FIG. 17 is a diagram showing replacement of dictionary data. The compression dictionary of FIG. 17 is extracted from the compressed data of the old version data by the compression information generation unit 122 of the development environment PC 1000. The compression / decompression combined dictionary in FIG. 17 shows a compression dictionary generated by the compression information generation unit 122 in which tokens are replaced in ascending order so that tokens can be easily searched. Here, if tokens are replaced, the pair part that has been replaced recursively is affected. That is, “00” surrounded by a broken line is “10” (that is, replaced with “50, 60”) in the original compression dictionary, but becomes “ABCD” when “10” is used as it is in the compression / decompression combined dictionary. End up. The same applies to “10” surrounded by a broken line. Therefore, in the compression dictionary, the token 10 on the second line is replaced with “50, 60”, but in the compression / decompression combined dictionary on the right side, replacement with 50, 60 is 00. Replace “10” with “00”. Similarly, “02” in the fifth line is replaced with “10”. Thus, after the tokens are arranged in ascending order, the compression / decompression combined dictionary can be created by changing the dictionary data of the compression dictionary so as to correspond. Since only the token is replaced here, the expansion speed is not affected, and the compression speed is not affected. By doing so, it is not necessary to send dictionary order information. The update data is essentially only difference information between the original difference data and information to be added to the dictionary.
(3) The development environment PC 1000 stores the compression / decompression combined dictionary and the compressed old version data in the NAND flash memory 260 of the embedded device 2000.

(Operation of environment development PC1000)
When it becomes necessary to create the difference data, the environment development PC 1000 creates the difference data as in the first embodiment, and the compression processing data transmission unit 130 transmits only the difference data to the embedded device 2000.

(Operation of embedded device 2000)
FIG. 18 is a diagram illustrating a configuration of the embedded device 2000 according to the third embodiment.
(1) The NAND flash memory 260 stores compressed old version data and a compression / decompression combined dictionary used for decompressing the compressed old version data.
(2) The difference data input unit 220 receives difference data from the development environment PC 1000.
(3) The data expansion unit 230 reads the compressed old version data stored in the NAND flash memory 260 and the compression / decompression dictionary, and uses the compression / decompression dictionary to compress the old version data. Expand.
(4) The difference application unit 240 creates new version data by applying the difference data received by the difference data input unit 220 to the old version data expanded by the data expansion unit 230.
(6) The built-in compression unit 250 compresses the new version data created by the difference application unit 240 using the compression / decompression dictionary, and stores the compressed new version data in the NAND flash memory 260.

  In the second embodiment, since only the difference data is transmitted from the development environment PC 1000 to the embedded device 2000, the data to be transmitted can be reduced.

In the above embodiment,
Software rewrite that upgrades the program version after shipment for embedded devices that have a part of the program code compressed and held on the NAND flash memory and that are loaded into the RAM and executed at runtime. In the system,
A computer device that is a program development environment
A binary difference extraction unit for extracting binary differences between old and new programs;
A compression unit that compresses the program code to generate an image to be stored in the NAND flash memory;
A compression state information generation unit indicating a compression state;
A transfer unit that transfers binary difference information and compression state information from the program development environment to the target embedded device;
The target embedded device is
A compression / decompression unit for decompressing an existing old program on a RAM from a compressed state;
A difference application unit that applies the difference information transferred to the old program developed on the RAM and changes the program to the new program;
A software rewriting system including a compression unit that compresses a new program created on the RAM using the transferred compression state information and stores it in the NAND flash memory has been described.

In the above embodiment,
The binary difference extraction unit
A computer apparatus, which is a program development environment in which a program is divided into fixed physical units and compared for each divided unit, has been described.

In the above embodiment,
The binary difference extraction unit
It is determined whether the extracted binary difference is larger than the compressed program code. If the binary difference is larger, the compressed program code is used as the difference data, and the extracted difference is combined with a flag indicating the information. A computer device that is a development environment has been described.

In the above embodiment,
The compression unit is
In particular, a computer apparatus in a program development environment, which is a compression method called byte pair compression, has been described.

In the above embodiment,
The compression state information generation unit
A computer apparatus which is a program development environment for generating a compression dictionary specific to compressed data has been described.

In the above embodiment,
The compression state information generation unit
A computer apparatus, which is a program development environment for generating a compression dictionary itself for byte pair compression, has been described.

In the above embodiment,
The compression state information generation unit
A computer apparatus, which is a program development environment that outputs the difference between the compression status information generated by the new version and the compression status information of the old program, has been described.

2 is a diagram illustrating an example of hardware resources of the PC 1000 and the embedded device 2000 according to Embodiment 1. FIG. 1 is a diagram illustrating a general update system according to Embodiment 1. FIG. FIG. 3 is a block diagram of the PC 1000 in the development environment according to the first embodiment. 6 is a flowchart of the operation of the PC 1000 according to the first embodiment. FIG. 5 shows an example of new and old data in the first embodiment. FIG. 6 is a diagram illustrating an example of compression of new edition data in the first embodiment. 2 is a block diagram of an embedded device 2000 according to Embodiment 1. FIG. 5 is a flowchart of the operation of the embedded device 2000 according to the first embodiment. FIG. 4 is a diagram illustrating an example of old version data in the first embodiment. FIG. 5 shows an example of new edition data in the first embodiment. 5 is a flowchart of the operation of the embedded device 2000 according to the first embodiment. 5 is a flowchart of the operation of the embedded device 2000 according to the first embodiment. FIG. 6 is a diagram illustrating an example of compression when there is compression state information in the first embodiment. FIG. 10 is a block diagram of a development environment PC 1000 according to the second embodiment. FIG. 9 is a diagram for explaining a development dictionary in the second embodiment. FIG. 10 is a block diagram of an embedded device 2000 according to the second embodiment. FIG. 10 is a diagram illustrating a compression / decompression combined dictionary according to Embodiment 3. FIG. 10 is a block diagram of an embedded device 2000 according to Embodiment 3.

Explanation of symbols

  11,1000 PC, 22,2000 Embedded device, 110 Difference extraction unit, 120 Compression processing unit, 122 Compression information generation unit, 130 Compression processing data transmission unit, 151 Old version program, 152 New version program, 153 Difference data, 155 Compression state information , 160 Data transfer unit, 210 RAM, 211 Old development data, 212 New development data, 213 Difference data, 214 Compression state information, 230 Data development unit, 240 Difference application unit, 250 Embedded side compression unit, 260 NAND flash memory 270 execution program, 280 program group, 281 execution program, 401 new version data, 402 old version data, 403 difference data.

Claims (12)

A difference data creation device for creating difference data indicating the change contents of the new version data which is the data after the change of the old version data with respect to the old version data which is the data before the change;
Applying the difference data created by the difference data creation device to the old version data, rewriting the old version data to create the new version data, and a new version data creation device using the created new version data; In the prepared data rewriting system,
The difference data creation device includes:
A difference data creation unit for creating the difference data from the new version data and the old version data;
A compression rule information creation unit that compresses the new version data and creates compression rule information indicating a compression rule of the new version data when the new version data is compressed,
The new edition data creation device
A compressed data storage unit for storing the compressed old version data;
A difference data input unit to which the difference data created by the difference data creation device and the compression rule information are input;
A decompression unit that reads and decompresses the compressed previous version data stored in the compressed data storage unit;
A difference application unit that creates the new version data by applying the difference data input to the difference data input unit to the old version data expanded by the expansion unit;
A compression unit that compresses the new version data created by the difference application unit based on the compression rule information input to the difference data input unit, and stores the compressed new version data in the compressed data storage unit; A data rewriting system characterized by comprising. The difference data creation unit
2. The data rewriting system according to claim 1, wherein the new version data and the old version data are separated by corresponding physical units, and the difference data is created for each divided unit. The compression rule information creating unit
The size of the difference data created by the difference data creation unit and the compressed new version data are determined, and the difference data is determined to be larger than the compressed new version data. In this case, the difference data replacement information including the compressed new version data and the index information indicating that the compressed new version data is replaced with the difference data,
The difference data input unit
The difference data substitution information created by the difference data creation device and the compression rule information corresponding to the compressed new edition data included in the difference data substitution information are input,
The compression unit is
When the difference data substitution information is input to the difference data input unit, the index information included in the difference data substitution information is detected. When the index information is detected, the compressed data included in the difference data substitution information is detected. 3. The data rewriting system according to claim 1, wherein the new version data and the compression rule information corresponding to the compressed new version data are stored in the compressed data storage unit in association with each other. The compression rule information creation unit and the compression unit are:
4. The data rewriting system according to claim 1, wherein the new edition data is compressed by a byte pair compression method. The compression rule information creating unit
5. The data rewriting system according to claim 4, wherein a compression dictionary in the byte pair compression method is created as the compression rule information. The new version data is created by rewriting the old version data by applying the difference data indicating the change contents of the new version data which is the data after the change of the old version data with respect to the old version data which is the data before the change to the old version data. In the new version data creation device using the created new version data,
A compressed data storage unit for storing the compressed old version data;
A differential data creation device that creates the differential data from the new version data and the old version data, and includes compression rule information indicating a compression rule of the new version data when compressing the new version data and compressing the new version data. A difference data input unit to which the difference data created by the difference data creation device to create and the compression rule information are input;
A decompression unit that reads and decompresses the compressed previous version data stored in the compressed data storage unit;
A difference application unit that creates the new version data by applying the difference data input to the difference data input unit to the old version data expanded by the expansion unit;
A compression unit that compresses the new version data created by the difference application unit based on the compression rule information input to the difference data input unit, and stores the compressed new version data in the compressed data storage unit; New edition data creation device characterized by having. In the difference data creation device for creating difference data indicating the change contents of the new version data which is the data after the change of the old version data with respect to the old version data which is the data before the change,
A difference data creation unit for creating the difference data from the new version data and the old version data;
A compression rule information creating unit that compresses the new version data and creates compression rule information indicating a compression rule of the new version data when the new version data is compressed;
A new version data creation device that creates the new version data using the difference data, the compressed data storage unit storing the compressed old version data, the difference data created by the difference data creation device, and the compression A difference data input unit that receives rule information; a decompression unit that reads and decompresses the compressed old version data stored in the compressed data storage unit; and the difference in the old version data decompressed by the decompression unit A difference application unit that creates the new version data by applying the difference data input to the data input unit, and the compressed data received by the difference data input unit for the new version data created by the difference application unit And a compression unit that compresses the compressed new version data and stores the compressed new version data in the compressed data storage unit. The data creating apparatus, the differential data creating apparatus characterized by comprising a compression rule information transmitting unit that transmits said compression rule information and the difference data. The new version data is created by rewriting the old version data by applying the difference data indicating the change contents of the new version data which is the data after the change of the old version data with respect to the old version data which is the data before the change to the old version data. In the new edition data creation program,
(1) storing the compressed old version data;
(2) A differential data creation device that creates the difference data from the new version data and the old version data, and compresses the new version data and indicates a compression rule for the new version data when the new version data is compressed. Processing for receiving the difference data and the compression rule information created by the difference data creation device for creating rule information;
(3) a process of reading and decompressing the stored compressed previous version data;
(4) A process of creating the new version data by applying the received difference data to the developed old version data;
(5) processing for compressing the created new edition data based on the received compression rule information and storing the compressed new edition data;
A new edition data creation program characterized by causing a computer to execute. In the difference data creation program for creating difference data indicating the change contents of the new version data which is the data after the change of the old version data with respect to the old version data which is the data before the change,
(1) Processing for creating the difference data from the new version data and the old version data;
(2) a process of compressing the new version data and creating compression rule information indicating a compression rule of the new version data when the new version data is compressed;
(3) A new version data creation device that creates the new version data using the difference data, and receives a compressed data storage unit that stores the compressed old version data, the difference data, and the compression rule information. A difference data input unit; a decompression unit that reads and decompresses the compressed previous version data stored in the compressed data storage unit; and the old version data decompressed by the decompression unit is received by the difference data input unit And applying the difference data to compress the new version data created by the difference application unit based on the compression rule information received by the difference data input unit. The new version data creation device further includes a compression unit that stores the compressed new version data in the compressed data storage unit. Process of transmitting said compression rule information,
A difference data creation program characterized by causing a computer to execute. The new version data is created by rewriting the old version data by applying the difference data indicating the change contents of the new version data which is the data after the change of the old version data with respect to the old version data which is the data before the change to the old version data. In the new version data creation device using the created new version data,
A compressed data storage unit for storing the compressed old version data;
A decompression dictionary storage unit for storing a decompression dictionary used for decompressing the compressed old version data stored in the compressed data storage unit;
A difference data input unit to which the difference data created by the difference data creation device that creates the difference data from the new version data and the old version data is input;
The compressed old version data stored in the compressed data storage unit and the expansion dictionary stored in the expansion dictionary storage unit are read, and the compressed old version data is read using the expansion dictionary. A deployment section to deploy;
A difference application unit that creates the new version data by applying the difference data input to the difference data input unit to the old version data expanded by the expansion unit;
A compression unit that compresses the new version data created by the difference application unit using the expansion dictionary stored in the expansion dictionary storage unit, and stores the compressed new version data in the compressed data storage unit; New edition data creation device characterized by comprising: The difference data creation device that creates the difference data includes:
When the old version data is compressed and the old version data is compressed, a compression dictionary indicating a compression rule of the old version data is created, and the development of the old version data and the new version data are corrected by correcting the created compression dictionary. Create a compression / decompression dictionary that is also used for compression,
The expansion dictionary storage unit
11. The new version data creation device according to claim 10, wherein the compression / decompression combined dictionary is stored as the expansion dictionary. The difference data input unit
The difference data and the correction rule information generated by the difference data generation device that generates correction rule information indicating a correction rule for generating the difference data and correcting the expansion dictionary to a compression dictionary used for compression of the new edition data Is entered,
The compression unit is
According to the modification rule information input to the difference data input unit, the expansion dictionary stored in the expansion dictionary storage unit is corrected to the compression dictionary, and the new version data created by the difference application unit is expanded. 11. The new version data creating apparatus according to claim 10, wherein the new version data is compressed using the compression dictionary modified from a dictionary, and the compressed new version data is stored in the compressed data storage unit.

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