JP7245876B2 - Drive recorder storage device control method and storage device control system - Google Patents

Description

The present invention generally relates to control methods and control systems, and more particularly to control methods and storage device control systems for drive recorder storage devices.

A file system is a system for managing files in a storage device (eg, SD card or hard drive) and operating the storage device efficiently. File Allocation Table (FAT) is a common file system.

FIG. 1 shows a schematic diagram of a storage device 900 employing the FAT file system. Storage device 900 includes FAT 920 , directory entries 930 and a plurality of data clusters 940 . Taking a drive recorder as an example, after multiple operations of writing and deleting a file, the data of the same file can be distributed and stored in non-contiguous data clusters 940 . For example, as shown in FIG. 1, file FA is stored in data clusters numbered "13", "14", "15", "19" and "20".

Directory entry 930 records the file name and starting data cluster number in storage device 900 . FAT 920 records the FAT chain of data clusters. For example, directory entry 930 indicates that file FA is stored in storage device 900, and data of file FA is stored in data cluster 940 numbered "13." In the FAT 920, the position corresponding to the data cluster 940 numbered "13" is "14", which indicates that the data cluster 940 numbered "14" stores subsequent data of the file FA. ing. In the FAT 920, the position corresponding to the data cluster 940 numbered "14" is "15", which indicates that the subsequent data of the file FA is stored in the data cluster 940 numbered "15". and so on. In the FAT 920, the position corresponding to the data cluster 940 numbered "20" is "EOC", which means that the data cluster 940 numbered "20" is the end of the cluster chain (EOC) of the data cluster 940. is shown.

FIG. 2 shows a flowchart of a method for writing drive recorder files. FIG. 3 is a schematic diagram of a storage device 900 operating according to FIG. For example, after the recording process of the drive recorder is activated, the FAT920 in the storage device 900 is copied to dynamic random access memory (DRAM) (step S901). Then, according to the FAT in the DRAM, it is determined whether the storage space in the storage device 900 is sufficient (step S902). If there is enough storage space in the storage device 900, one data cluster is selected as the starting data cluster (for example, the data cluster numbered "16") for writing data (step S903), and the file name ( FB) and the number of the starting data cluster (eg "16") are added. Next, another data cluster (for example, data cluster numbered "17") for writing data is selected (step S905), and in the FAT in the DRAM, at a position corresponding to data cluster numbered "16", A data cluster number (for example, "17") is recorded (step S906), and data is written to the data cluster (step S907). The above steps are repeated until the file writing process is completed. Also, when the FAT in the DRAM is updated a predetermined number of times (for example, three times), the FAT 920 in the storage device 900 is updated according to the FAT in the DRAM until the file writing process is completed. When the file writing process is completed, the drive recorder updates the FAT 920 in the storage device 900 again according to the FAT in the DRAM.

However, an unexpected power outage due to a car accident can result in read errors due to an incomplete FAT chain. For example, as shown in FIG. 3, when an unexpected power failure occurs after the data of file FB is written to the data cluster numbered "29", the FAT 920 in the storage device 900 is still updated according to the FAT in the DRAM. Therefore, the FAT chain of data FB is incomplete, and the data of file FB stored in data clusters numbered "22" and "29" cannot be read. For drive recorders, failing to read data related to car accidents is a very serious problem.

The present invention relates to a drive recorder storage device control method and a storage device control system that configures a storage device according to a prescribed file allocation table (FAT) and prescribed directory entries to prevent read failures due to unexpected power failure.

According to one aspect of the present invention, a method for controlling a storage device of a drive recorder is provided. A method for controlling a storage device of a drive recorder includes steps of configuring a directory entry of the storage device according to a predetermined directory entry stored in the storage unit; and controlling the controller to write data to the storage device according to the directory entries and the FAT.

According to another aspect of the invention, a storage device control system is provided. A storage device control system includes a storage unit, a controller, and a processor. The storage unit stores a prescribed directory entry and a prescribed FAT. The controller writes data to the storage device. The processor controls the controller to configure directory entries of the storage device according to the predetermined directory file, configure the FAT of the storage device according to the predetermined FAT, and write data to the storage device according to the directory file and the FAT. Execute the step and

According to another aspect of the present invention, there is provided a control method for a storage device of a drive recorder. The method comprises the steps of configuring the directory entries of the storage device according to predetermined directory entries stored in the storage unit and configuring the FAT of the storage device according to a predetermined file allocation table (FAT) stored in the storage unit. , controlling the controller to write data to the storage device according to the directory entries and the FAT, wherein the entries in the FAT correspond to respective predetermined clusters in the storage device, each entry in the FAT: Each given cluster in the storage device remains unchanged after new data is written.

According to one aspect of the invention, the data includes data from at least two files, and the FAT is configured to store the two files in interleaved clusters.

According to another aspect of the invention, the at least two files are video files having the same bitrate, and the step of configuring the FAT of the storage device includes creating the same number of predetermined clusters in each of the at least two files. Including assigning step.

According to yet another aspect of the invention, the at least two files are video files having different bitrates from each other, and the step of configuring the FAT of the storage device comprises: assigning a predetermined cluster to each of the files;

According to another embodiment, a storage device control system is provided. The system includes a storage unit that stores predetermined directory entries and a predetermined file allocation table (FAT), a controller that writes data to the storage device, and a processor. configuring a directory entry; configuring a FAT of a storage device according to a predetermined FAT; controlling a controller to write data to the storage device according to the directory entry and the FAT; corresponds to each given cluster in the storage device, and each entry in the FAT remains unchanged after new data is written to each given cluster in the storage device.

The above and other aspects of the present invention will become better understood with regard to the following detailed description of non-limiting embodiments. Description will be made below with reference to the drawings.

1 is a schematic diagram of a storage device employing a prior art FAT file system; FIG. 1 is a flow chart of a method for writing files of a prior art drive recorder; 3 is a schematic diagram of a storage device that performs the operations of FIG. 2; FIG. 1 is a block diagram of a control system according to one embodiment of the invention; FIG. 4 is a flow chart of a method for controlling a storage device of a drive recorder according to an embodiment of the present invention; 1 is a schematic diagram of a storage device configured with directory files and a file allocation table (FAT) according to an embodiment of the present invention; FIG. 4 is a flowchart of writing data to a storage device according to one embodiment of the present invention; 8 is a schematic diagram of a storage device that performs the operations of FIG. 7; FIG. Fig. 3 shows the organization of pre-configured contiguous data clusters according to an embodiment of the invention; FIG. 4 illustrates the configuration of preconfigured contiguous data clusters to support multiple files from different or the same application, according to one embodiment of the present invention; 11 is a schematic diagram illustrating a potential drawback of the file storage approach shown in FIG. 10; FIG. 11 is a schematic diagram illustrating a potential drawback of the file storage approach shown in FIG. 10; FIG. 1 is a schematic diagram of a storage device configured with interleaved FATs according to an embodiment of the present invention; FIG. Figure 4 illustrates a method of storing data in multiple clusters consistent with an interleaving technique, according to one embodiment of the present invention; 1 is a schematic diagram of a storage device configured with a modified interleaved FAT according to one embodiment of the present invention; FIG. Figure 4 illustrates a method of storing data in multiple clusters consistent with a modified interleaving technique, according to one embodiment of the present invention; FIG. 4 is a schematic diagram of another modified interleaved FAT configured storage device according to an embodiment of the present invention; FIG. 4 illustrates a method of storing data in multiple clusters consistent with another modified interleaving technique, according to an embodiment of the present invention; FIG.

Considering the problem of the storage device of the prior art drive recorder, the present invention configures the FAT and directory entries of the storage device according to a predetermined File Allocation Table (FAT) and predetermined directory entries to prevent readout due to unexpected power failure. Provided are a drive recorder storage device control method and a storage device control system that prevent failure.

FIG. 4 shows a block diagram of control system 100 in accordance with one embodiment of the present invention. For example, control system 100 is a control chip. In this embodiment, control system 100 is connected to video camera 200 and storage device 400 . Control system 100 and video camera 200 may be provided, for example, in a drive recorder. The storage device 400 is, for example, an SD card or hard drive, and may be internal or external to the drive recorder. Control system 100 includes storage 110 , controller 120 , and processor 130 . Storage unit 110 stores a predetermined directory entry and a predetermined FAT. Controller 120 writes data to storage device 400 . Processor 130 configures the directory entries and FAT of storage device 400 .

FIG. 5 shows a flow chart of a control method for a drive recorder storage device according to an embodiment of the present invention. In this embodiment, the processor 130 checks whether the directory entry and FAT exist in the storage device 400 each time the drive recorder is started or the storage device 400 is replaced (step S501). If not present, the processor 130 directly configures the directory entry and the FAT in the storage device 400 according to the predetermined directory entry and the predetermined FAT in the storage unit 110 (step S503). It is checked whether the directory entry and FAT in storage device 400 are the same as the prescribed directory entry and prescribed FAT in storage unit 110 (step S502). If not, processor 130 directly configures the directory entry and FAT in storage device 400 according to the prescribed directory entry and prescribed FAT in storage unit 110 (step S503).

FIG. 6 shows a schematic diagram of a storage device 400 configured with directory entries and FATs, according to one embodiment of the present invention. Storage device 400 includes FAT 420 configured according to a predetermined FAT, directory entries 430 configured according to a predetermined FAT, and a plurality of data clusters 440 .

As shown in FIG. 6, in directory entry 430, processor 130 configures the file name FC corresponding to the file and the starting data cluster corresponding to file FC as the data cluster numbered "11", and in FAT 420, processor 130 further configures the FAT chain corresponding to the file FC as data clusters numbered "11" to "15". Similarly, in directory entry 430, processor 130 configures the corresponding file name FD and the starting data cluster corresponding to file FD as the data cluster numbered "16", and in FAT 420, processor 130 further configures file FD , as data clusters numbered "16" to "20".

That is, the data of the file FC is preset to be stored in the data clusters numbered "11" to "15", and the data of the file FD is stored in the data clusters numbered "16" to "20". It is preset as Although the directory entry 430 and the FAT 420 have already been configured, in the storage device 400, as shown in FIG. clusters) are not stored with the data corresponding to files FC and FD.

FIG. 7 shows a flowchart of writing data to storage device 400 according to one embodiment of the present invention. In this embodiment, processor 130 controls controller 120 to write data to storage device 400 according to directory entries 430 and FAT 420 .

For example, when the drive recorder starts recording, processor 130 selects a file for writing data according to directory entry 430 (step S704). In one embodiment, the filenames in directory entry 430 carry time information so that processor 130 can select the oldest file to write data to according to the filenames in directory entry 430 . For example, looking at FIG. 6, file FC is the oldest file.

Next, processor 130 changes the file name in directory entry 430 corresponding to that file (step S705). Continuing the above example, processor 130 changes the file name of the file that processor 130 selects to write data from "FC" to "FE" in directory entry 430, as shown in FIG. Note that in directory entry 430, the starting data cluster corresponding to file FE is unchanged and is still the data cluster numbered "11". Further, in FAT420, the FAT chain corresponding to file FE is unchanged and remains data clusters numbered "11" to "15".

Processor 130 controls controller 120 to write data to data clusters in storage device 400 configured for the file (step S706). Continuing with the above example, processor 130 controls controller 120 to sequentially write data to data clusters numbered "11" through "15" in storage device 400, as shown in FIG.

Processor 130 then determines whether to continue writing data (step S707). If the writing of data continues, steps S704-S706 are repeated, otherwise the process ends.

From the above, it can be seen that the FAT 420 is not updated while the processor 130 writes data to the storage device 400 . Therefore, even if the drive recorder encounters an unexpected power loss, the FAT chain corresponding to the files in the FAT will remain intact and the data in the files in the storage device 400 can still be read completely.

Furthermore, in the prior art, the processor has to spend time searching for empty data clusters to write data. After multiple file write and delete operations, empty data clusters are usually in fragments, which degrades file write performance. Compared to the prior art, the data clusters of the file in the present invention are preconfigured and unchanged, which means the processor does not have to spend time searching for empty clusters to write data. This will improve file write performance. In one embodiment, clusters of files may be configured as contiguous (as shown in FIG. 6) to further improve file write performance.

Additionally, in the prior art, the processor must determine if the available space is sufficient before writing data. If insufficient space is available, the processor should remove the filename and starting data cluster corresponding to at least one file from the directory entry, and remove the FAT chain corresponding to at least one file from the FAT , which degrades file write performance. Compared to the prior art, the processor 130 of the present invention also removes the file name and starting data cluster from the directory file and removes the file name and starting data cluster from the FAT without having to determine if the available space is sufficient before writing data. File write performance is further improved since the FAT chain does not need to be deleted.

FIG. 9 illustrates the organization of preconfigured contiguous data clusters according to one embodiment of the present invention. If the FAT is preconfigured in the form of contiguous data clusters, as described in connection with FIG. 6, the files are stored sequentially in clusters as shown in FIG. That is, in a Secure Digital (SD) card, for example, the memory is divided into N sections, each section having a data space of, for example, 1000 contiguous clusters. Files are written sequentially into these N sections, with new files cyclically overwriting previous old files. The technique shown in FIG. 9 works well for simple applications, e.g., recording only one video file at a time, but as the complexity of production applications increases, e.g., two or more videos (or other There are more and more applications that can record files of any kind.

In this regard, FIG. 10 illustrates the configuration of preconfigured contiguous data clusters supporting multiple files from different applications, according to one embodiment of the present invention. For example, two types of files in the form of large/small files corresponding respectively to higher resolution and lower resolution video can be stored in memory substantially simultaneously. In another example, for example, a multi-lens application may be implemented that includes video files corresponding to front and rear lenses, also stored substantially simultaneously in memory. Thus, as shown in FIG. 10, in one example, the front (F) and rear (R) cameras are allocated the same number of sections (eg, N) for storing video files. If the recording time of each video file is, for example, 1 minute, the F file X and the R file X will be written simultaneously for 1 minute.

11A and 11B are schematic diagrams illustrating potential drawbacks of the file storage approach shown in FIG. 11A, SD storage 1110 includes boot sector 1120, FAT 1130, directory entry 1140, and multiple data clusters 1150, also shown logically as 1160 and 1170 in FIG. 11B. Furthermore, in a situation where you want to store two video files at the same time, the conventional method of writing, for example, F-file X and R-file X to SD storage 1110 at the same time is to store F-file X in clusters 1100-2099, as shown in FIG. 11B. It relies on storage by clusters, where R-file X is stored contiguously in clusters 20100-21099. In this case, FAT 1130 is preconfigured to store different files in predetermined clusters.

However, when multiple files are written to the SD storage 1110 at the same time in this way, an undesirable phenomenon occurs that reduces the efficiency of consecutive SD write operations. More specifically, SD write operations are based on clusters, so when F-file X and R-file X are (substantially) simultaneously written to SD storage 1110, the actual behavior is that F-file X After several clusters have been written, the system switches to writing R-file X to several clusters. The system continues to switch between the two files as indicated by numbers 1-8 in FIG. 11B. As a result, the SD storage 1110 cannot continuously write in the next adjacent cluster, but instead "jumps" to a distant cluster to write another file. This phenomenon is sometimes called "random write" or "random jump" which reduces SD write operation efficiency.

FIG. 12A is a schematic diagram of a storage device configured with interleaved directory files and FATs, according to one embodiment of the present invention, and FIG. shows how data is stored in clusters. In FIG. 12A, SD storage 1210 includes boot sector 1220, FAT 1230, directory entry 1240, and multiple data clusters 1250, also shown logically as 1260 in FIG. 12B.

To address the random write problem described with reference to FIGS. 11A and 11B, cluster lists of related video files stored in FAT 1230 are formatted or configured to be interleaved. Importantly, cluster interleaving eliminates the random write phenomenon. This interleaved distribution technique can be based on the bitrate composition ratio of each video file in the cluster.

As an example, assume that the bit rate ratio between F file X and R file X is 1:1. In such a case, FAT 1230 is formatted or configured so that each successive cluster of F-file X and R-file X is interleaved equally with each other, resulting in data clusters stored as shown in multiple data clusters 1250 and 1260. .

Of course, the bitrate ratio of the F file, X, and R file, X, can be scaled up by K times, and is generally expressed as K:K (eg, K=2). In such cases, the cluster lists of the two video files can be interleaved as shown in FIGS. 13A and 13B, in that the interleaved cluster ratio is not limited from single cluster to single cluster. , sometimes referred to as "modified" interleaved directory files and FATs. Thus, Figure 13A shows an SD storage 1310 including a boot sector 1320, a FAT 1330, a directory entry 1340, and a plurality of data clusters 1350, also shown logically as 1360 in Figure 13B, as shown. , F file X, and R file X are assigned two clusters (K=2) in an interleaved manner. Thus, interleaved FAT 1330 and data clusters 1350 address the random write phenomenon even as the demand for additional clusters for each independent file increases.

FIG. 14A is a schematic diagram of another modified interleaved FAT organized storage device according to an embodiment of the present invention, and FIG. 14B is another modified according to an embodiment of the present invention. shows how data is stored in multiple classes consistent with the interleaving scheme used. FIG. 14A shows SD storage 1410 including boot sector 1420, FAT 1430, directory entry 1440, and multiple data clusters 1450, also shown logically as 1460 in FIG. 14B. FIGS. 14A and 14B show that the bitrate ratios of F file X and R file X do not necessarily have a 1:1 ratio, but can instead have unequal ratios such as 2:1. . Thus, two clusters are allocated to F-file X for each cluster allocated to R-file X, as shown in FAT 1430 . Multiple data clusters 1450 and 1460 illustrate this same allocation example.

From the above, it will be appreciated by those skilled in the art that undesirable random write phenomena can occur when storing multiple files for each file in separate but contiguously allocated clusters. This phenomenon degrades the SD write performance. The interleaving approach described herein addresses this deficiency. Furthermore, the cluster list interleaving of each (video) file is constructed in the format according to the bitrate ratio between the video files. As files are recorded, the system switches SD writes between files according to the bitrate ratio. And, significantly, SD random writes are avoided, resulting in sequential cluster writes that help maintain SD write efficiency.

As discussed with respect to the embodiments of Figures 4-7, in the event of an unexpected power failure, the last written data can still be found because there is a complete data link. Also, when looping recording, the shift is more efficient because old files are not deleted, only the file name is changed in the directory entries (430, 1140, 1240, 1340, 1440). Both of these advantages remain associated with the interleaving approach described herein.

The interleaving approach can also use the bit rate ratio between substantially simultaneously recorded (video) files to configure the allocation of each cluster. During the formatting stage, the cluster list is interleaved. When this group of files (eg, F file X and R file X) are recorded at substantially the same time, the system interlaces SD writes to different files according to the configured cluster number ratio. This combination can achieve sequential cluster writes and maintain the efficiency of SD writes.

Finally, it is noted that the described cluster list interleaving mechanism is not limited to only two video files (e.g., F file X and R file X), but can also be applied to three or more interleaved video file clusters. sea bream.

While the present invention has been described by way of example and with respect to the above embodiments, it should be understood that the present invention is not so limited. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and therefore the scope of the appended claims is the broadest to encompass all such modifications and similar arrangements and procedures. An interpretation should be given.

This application is a continuation-in-part of U.S. patent application Ser. and both subject matter are incorporated herein by reference.

Claims (20)

A control method for a storage device of a drive recorder,
configuring directory entries of the storage device according to predetermined directory entries stored in the storage unit;
configuring the FAT of the storage device according to a predetermined file allocation table (FAT) stored in the storage unit;
controlling a controller to write data to the storage device according to the directory entry and the FAT;
Entries in the FAT correspond to respective predetermined clusters in the storage device, and each entry in the FAT changes after new data is written to the respective predetermined clusters in the storage device. not ,
The method of control, wherein the data includes data from at least two files, and wherein the FAT is configured to store the two files in interleaved clusters. wherein the at least two files are video files having the same bitrate, and configuring the FAT of the storage device includes assigning the same number of the predetermined clusters to each of the at least two files; The control method according to claim 1 . The at least two files are video files having bitrates different from each other, and the step of configuring the FAT of the storage device comprises: converting each of the at least two files according to the bitrates of the at least two files; 2. A control method according to claim 1 , comprising the step of assigning predetermined clusters. Configuring the directory entries of the storage device comprises:
2. A control method according to claim 1, comprising configuring a file name corresponding to a file in said directory entry. Configuring the directory entries of the storage device comprises:
5. The control method of claim 4 , comprising configuring a starting data cluster corresponding to said file in said directory entry. The step of configuring the FAT of the storage device comprises:
6. The control method of claim 5 , comprising configuring a FAT chain corresponding to said file in said FAT. controlling the controller to write data to the storage device according to the directory entry and the FAT;
updating the file name corresponding to the file in the directory entry;
and controlling the controller to write data to data clusters in the storage device configured for the file. 8. A control method according to claim 7 , wherein in said directory entry said starting data cluster corresponding to said file remains unchanged. 9. The control method of claim 8 , wherein in the FAT, the FAT chain corresponding to the file remains unchanged. The step of configuring the FAT includes:
2. A control method as claimed in claim 1, comprising the step of constructing a specific ratio of clusters corresponding to said at least two files. A storage device control system,
a storage unit that stores a predetermined directory entry and a predetermined file allocation table (FAT);
a controller that writes data to a storage device;
a processor, the processor comprising:
configuring directory entries of the storage device according to the predetermined directory entries;
configuring the FAT of the storage device according to the predetermined FAT;
controlling the controller to write data to the storage device according to the directory entry and the FAT;
Entries in the FAT correspond to respective predetermined clusters in the storage device, and each entry in the FAT changes after new data is written to the respective predetermined clusters in the storage device. and
A storage control system, wherein the data includes data from at least two files, and wherein the FAT is configured to store the two files in interleaved clusters. The at least two files are video files having the same bitrate, and the step of configuring the FAT of the storage device comprises assigning the same number of predetermined clusters to each of the at least two files. Item 12. The storage device control system according to Item 11 . The at least two files are video files having bitrates different from each other, and the step of configuring the FAT of the storage device comprises: converting each of the at least two files according to the bitrates of the at least two files; 12. The storage control system of claim 11 , including the step of allocating predetermined clusters. Configuring the directory entries of the storage device comprises:
12. The storage control system of claim 11, comprising configuring a file name corresponding to a file in said directory entry. Configuring the directory entries of the storage device comprises:
15. The storage control system of claim 14 , comprising configuring a starting data cluster corresponding to said file in said directory entry. The step of configuring the FAT of the storage device comprises:
16. The storage control system of claim 15 , comprising configuring a FAT chain corresponding to said file in said FAT. controlling the controller to write data to the storage device according to the directory entry and the FAT;
renaming the file name corresponding to the file within the directory entry;
and controlling the controller to write data to data clusters in the storage device configured for the file. 18. The storage control system of claim 17 , wherein in said directory entry said starting data cluster corresponding to said file remains unchanged. 19. The storage control system of claim 18 , wherein in the FAT, the FAT chain corresponding to the file remains unchanged. 12. The storage device control system of claim 11, wherein configuring the FAT of the storage device comprises configuring a specific ratio of clusters corresponding to the at least two files.

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