CN109326307B - Disc streaming method - Google Patents

Abstract

The invention discloses an optical disc streaming recording method, comprising the following steps: including at least two optical disc images, a user application program continuously writes file data and directory information where the files are located into the optical disc images; the optical disc image includes a first optical disc For the mirror image and the second optical disc image, when the storage space of the first optical disc image in use is used up, the file data is divided, a part of the data of the file is written into the first optical disc image, and the subsequent data of the file is written into the second optical disc image. The beneficial effects of the present invention are: on the one hand, the space efficiency of the optical disc is maximized, and on the other hand, it can be recognized that a certain file may be distributed on one or more optical discs during reading.

Description

Disc streaming method

technical field

The invention relates to the technical field of computers, in particular to a method for stream recording of an optical disc.

Background technique

At present, the general data archive storage media are magnetic disks, magnetic tapes and optical disks. More and more important data needs to be stored for a long time. Among them, optical disk storage has the characteristics of low maintenance cost for long-term storage, and can reliably store optical disks for more than 30 years. Although the write performance of the optical disc is poor and the number of writes is small, this happens to be in line with the characteristics of cold data read more and write less. Therefore, based on the characteristics of high security, high reliability, long life and low cost of optical discs, more and more enterprises choose optical disc libraries as storage media.

However, the capacity of a single disc is still relatively small. The CD disc is about 700MB, and the DVD disc is 4.7GB on one side, and can record about 4.59G of data at most (because the DVD's 1GB=1000MB, and the hard disk's 1GB=1024MB) (double-sided 8.5GB, up to about 8.3GB) Data), Blu-ray (BD) is relatively large, BD single-sided single-layer 25GB, double-sided 50GB, four-layer 100GB, the current 300GB disc has also been available. The holographic disc of Tokyo Institute of Technology in Japan has a capacity of 2TB. However, the capacity of a single disk is still not comparable to that of hard disks and tapes.

Using the optical disc library can combine the physical space separated by a large number of optical discs into a large logical space, that is, using the optical disc library virtualization mechanism to virtualize multiple optical discs into a large-capacity storage pool externally. In order to improve the overall performance, ease of use and usability of the CD library system, when a user uses this CD library, the data is first written into a series of CD images in the CD library hard disk cache. Once a certain image is full, it will be closed. The image is turned into a read-only image, and finally the image is completely burned to the corresponding physical disc, so a complete data set can be transparently burned to multiple physical discs. In practical applications, users continuously write data into the optical disc library. The system needs to write the stream-written files or directories into a series of disc images sequentially and reasonably. This requires the system to automatically divide the images to ensure that each image does not exceed the size of the disc. At the same time, try to ensure the continuity of the file directory itself; on the other hand, it is necessary to make full use of the storage space of the mirror image to avoid the waste of the storage space of the optical disc.

However, the current method of CD burning for large-capacity data sets mainly uses the method of first fully caching and then statically splitting, that is, the data set to be burned is completely saved in the hard disk, and then the data set is statically divided. After the division is completed, Burn each split sub-data set to disc. However, this static offline segmentation method is not suitable for online streaming recording mode. In the case of streaming recording, that is, new files or directories are constantly being written, the system cannot determine the size and boundaries of the currently written directories and files in advance, and thus cannot perform static data set segmentation.

A feasible method is to save a batch of files in the hard disk cache first, and then use the traditional static partition method. However, this requires a lot of hard disk space to cache the data to be recorded in this batch; at the same time, it also introduces additional write data streams and partition data streams, which will compete for I/O with the hard disk, thereby reducing the actual data writing performance. ; More importantly, the batch division itself is very difficult. In the online case, it cannot be guaranteed that the file data in a batch is exactly an integer multiple of the disc capacity, then the remaining space of the last disc in this batch will be in the next batch. It is also inconvenient to use during the recording process.

Therefore, there is a need for a method that can realize streaming data recording for an optical disc, on the one hand, to ensure the continuity of the storage process, and on the other hand, to maximize the storage efficiency of the optical disc storage space.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an optical disc streaming recording method, which on the one hand maximizes the space efficiency of the optical disc, and on the other hand, can recognize that a certain file may be distributed on one or more optical discs during reading.

In order to achieve the above object, the technical scheme of the present invention is

A method for stream recording of an optical disc, comprising the steps of:

At least two disc images are included, and the user application program continuously writes the file data and the directory information where the file is located into the disc images;

The optical disc image includes a first optical disc image and a second optical disc image. When the storage space of the first optical disc image in use is used up, the file data is divided, a part of the data of the file is written into the first optical disc image, and the subsequent data of the file is written into the second disc image.

Preferably,

The divided files stored in the first optical disc image and the second optical disc image are respectively added with identification files, the content of the identification file in the first optical disc image includes the ID of the second optical disc image, and the content of the identification file in the second optical disc image includes ID of the first disc image.

Preferably, when creating a directory, the system allocates an optical disc cluster for the directory, and maintains the update of the directory data in the memory, and when the directory is closed, writes the cluster involved in the directory into the corresponding position of the first optical disc image;

If the first optical disc mirror system reports that there is no free space abnormality during the writing process, the directory will be created in the second optical disc image; when the second optical disc image creates a directory, the directory will be created in the second optical disc image first. All pre-order directories in the absolute path of , then create themselves, and finally when the directory is closed, write all the updated clusters to the corresponding position of the second optical disc image.

Preferably, when the user writes a file, the pre-order directory information in the absolute path of the file is created until the root directory; after the pre-order directory is created, the file metadata is created, and the file data is started to be written; in the process of creating the directory , when the disc file system reports that there is no free space, the directory will be created to the next disc;

During the file writing process, when the first optical disc mirror system reports that there is no free space abnormality; select the second optical disc mirror image as the carrier for subsequent data storage, and obtain the ID of the second optical disc mirror image;

Then detect the remaining number of clusters in the first optical disc image, if the actual number of remaining free clusters is greater than a threshold; create a first identification file in the first optical disc image, the first identification file name is composed of the original file name and a digital mark, the first identification file The content of the file includes the ID of the second optical disc image where the subsequent data content of the file is recorded; in the second optical disc image, recreate the pre-directory in the absolute path of the file, and then create a second identification file, the second identification file name It is composed of the original file name and the digital mark, and the content of the second identification file includes the ID of the first optical disc image where the previous part of the file data is located; finally, the subsequent data is written;

When detecting the number of remaining clusters in the first optical disc image, if the actual number of remaining clusters is less than a threshold, read out the contents of the clusters within the last threshold size of the first optical disc image and save them in the memory cache, and store them in the first optical disc image. Delete the content of these clusters, record the actual length of the current file in the file metadata; create a third identification file, the name of the third identification file is composed of the original file name and a digital mark, and the content of the third identification file includes recording the subsequent content of the file. The volume number of the second optical disc image; in the second optical disc image, re-create the pre-directory in the absolute path of the file, and then create a fourth identification file, the name of the fourth identification file is composed of the original file name and a digital mark, the first The content of the four-identification file includes the ID number of the first optical disc image; finally, the data of the clusters within the threshold size range stored in the memory and subsequent data are written in sequence.

The working principles of the present invention are as follows: 1. The present invention can create directories and write files in the optical disc image in a streaming manner without knowing the actual allocated space required by the current file directory. When the "out-of-space" (out-of-space) exception occurs, use the exception handling process to write the directory that cannot be created or the remaining data into the subsequent free disc. This approach simplifies system design, eliminating the need to track the amount of space remaining on a disc in real time.

2. When the disc image is not closed, the content of its internal data cluster can be modified. The present invention utilizes this point, when the remaining space of an optical disc image is not enough to reconstruct a marked file with the same name, the last few clusters of the file are read into the memory, then the content of the cluster is cleared, and a corresponding marking file is created. Finally, several clusters in memory are used as the content of subsequent files.

3. Using the principle that a file actually occupies at least two clusters, one cluster is the metadata of the file, and the other cluster file data content, the identification file can be created by reserving or artificially generating space for the two clusters.

When reading a CD file, if the directory where the file is located contains a file with the same file name but a special mark at the end, first read the file data, obtain the length of the file data from the metadata, and then read the subsequent files from the special file The ID of the CD where it is located, and then read the data content of the special file with the same name from the next CD according to the same file path, and spliced with the saved content of the previous file to obtain complete file data.

The identification file has the same file name as the file, but a special mark is added at the end of the identification file. The special mark can be "+" and serial number, for example, the first split file is "+1", if the If the disc still needs to be split, add "+2" to the file name and mark the subsequent split files of the file according to this rule.

The beneficial effect of the present invention is that directories can be created sequentially, or file data can be written into an optical disc image without knowing the final size of the currently written file or the actual allocated space for creating a directory. Through the efficient partitioning mechanism of the file object, the storage space of the optical disc can be fully utilized. Through the file name identification mechanism, the location of the disc where a split file is located is determined, so that the entire content of the file can be restored by merging.

Description of drawings

1 is a schematic diagram of the overall flow of streaming disc recording in the present invention;

2 is a flowchart of creating a directory in an embodiment of the present invention;

3 is a flow chart of writing a file in an embodiment of the present invention;

FIG. 4 is a flowchart of reading a file in an embodiment of the present invention.

Detailed ways

The specific embodiments of the present invention will be further described below with reference to the accompanying drawings and embodiments. The following examples are only used to illustrate the technical solutions of the present invention more clearly, and cannot be used to limit the protection scope of the present invention.

The technical scheme of the specific implementation of the present invention is:

Embodiment: FIG. 1 is a schematic diagram of the overall flow of streaming optical disc recording, FIG. 2 is a flow chart of creating a directory, FIG. 3 is a flow chart of writing a file, and FIG. 4 is a flow chart of reading a file.

User applications continuously stream files and directories to a set of free disc images. The optical disk image and the physical optical disk have the same physical storage space, each byte corresponds to each other, has a globally unique image identification ID, and has a local file system. Initially, the image can be written and changed, and directories and files can be created and updated in the image. When the data is written or the image storage space is used up, the image can be automatically closed to make it a read-only image. A read-only image can be written to one physical disc at a time.

Files and directories contain an absolute directory, that is, the full path from this file to the root directory.

Optical discs use clusters as the basic allocation storage block unit, each directory contains at least one cluster, each file contains at least 2 clusters, and one cluster contains file metadata information; the remaining clusters contain file data.

In this embodiment, as shown in Figure 1, it is assumed that a user needs to create a directory with a path of /A/B/C at a certain moment, and the file system of the current disc image (ID number is 1) throws a "no free space" (out -of-space), create the directory to the next CD image (ID number is 2).

Suppose the user needs to write a file whose path is /A/B/C.txt at a certain moment (the content of the file is aaabbbcccddef...), when the data aaabbb is written, the file system of the current disc image (ID number is 3) throws "No When the out-of-space is abnormal, create an identification file in the current disc image, and then automatically write the subsequent file data (cccddef...) into the next disc image (ID number is 4), and also file the file. logo.

Describe the concrete working process of the present invention in the embodiment below:

(1) The process of creating the directory /A/B/C is as follows:

(1-1) First, perform the create directory operation;

(1-2) Whether the file system of the current disc image (ID number is 1) throws an "out-of-space" exception, if so, go to step (1-3); if not, then Go to step (1-5);

(1-3) Create all the preceding directories (/, /A, /A/B) in the absolute path of the directory in the next CD image (ID number 2);

(1-4) Create the directory (/A/B/C);

(1-5) Write the updated cluster to the corresponding location of the CD where the directory is located;

(1-6) Complete the directory creation operation.

(2) The process of writing the file /A/B/C.txt is as follows:

(2-1) First, perform the write file operation;

(2-2) Whether the file system of the current first disc image (ID number 3) throws an "out-of-space" exception, if so, go to step (2-3); if not , then go to step (2-15);

(2-3) Select a new blank second disc image and obtain its ID (ID number is 4);

(2-4) Detect the number of remaining clusters of the current first disc. If the actual number of remaining space clusters is greater than a certain threshold (assuming 2), go to step (2-5); if it is less than, go to step (2-9) ;

(2-5) Create a new file with the same file name but with a special number mark (assuming "+1") at the end of the current first disc image (the file name is C+1, and the file content includes the subsequent content of the file) The disc image ID number 4);

(2-6) Recreate the pre-directory (/, /A, /A/B) of the absolute path of the file on the second CD-ROM image;

(2-7) Create a new file (the file name is C+1) with the file name of the meta file name but add a special number mark (assumed to be "+1") at the end of the second disc image, and add the file metadata in the file name. ID number 3 of the disc where the previous part of the file is located;

(2-8) Write subsequent data to a new file, go to step (2-15);

(2-9) Read out the data of the last 2 clusters and save them in the memory, and delete these data in the current disc image;

(2-10) Record the actual length of the current file in the metadata of file C;

(2-11) Create a new file (the file name is C+1) with the same file name but add a special number mark (assumed to be "+1") at the end of the current first disc image, and the content of the new marked file includes recording the CD image ID number of the subsequent content of the file 4);

(2-12) Recreate the pre-directory (/, /A, /A/B) of the absolute path of the file in the second CD-ROM image;

(2-13) Create a new file (the file name is C+1) with the file name of the meta file name but add a special number mark (assumed to be "+1") at the end of the second disc image, and add the file metadata in the file name. ID number 3 of the disc where the previous part of the file is located;

(2-14) Write the data of the two clusters in the memory and the subsequent data of the file into a new file; (2-15) Complete the file writing operation.

(3) The process of reading the file /A/B/C.txt is as follows:

(3-1) First, perform the read file operation;

(3-2) Whether the directory where the file is located contains a file with the same file name (C) but a special mark (“+1”) at the end, if so, go to step (3-3); if not, go to step (3-3) steps (3-7);

(3-3) Obtain the length of the file data from the file metadata, and read the corresponding file data;

(3-4) Read the ID number 4 of the CD where the subsequent file is located from the special file;

(3-5) Read the data content of the special file (C+1) from the CD with ID number 4 according to the same file path (/A/B);

(3-6) Splicing the content with the previous file content to obtain the complete file content;

(3-7) Complete the read file operation.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principles of the present invention, several improvements and modifications can be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.

Claims (1)

1. a kind of CD streaming recording method, is characterized in that, comprises the steps: At least two disc images are included, and the user application program continuously writes the file data and the directory information where the file is located into the disc images; The optical disc image includes a first optical disc image and a second optical disc image. When the storage space of the first optical disc image in use is used up, the file data is divided, a part of the data of the file is written into the first optical disc image, and the subsequent data of the file is written into the second disc image; The divided files stored in the first optical disc image and the second optical disc image are respectively added with identification files, the content of the identification file in the first optical disc image includes the ID of the second optical disc image, and the content of the identification file in the second optical disc image includes ID of the first disc image; When creating a directory, the system allocates an optical disc cluster for the directory, and maintains the update of the directory data in the memory, and when the directory is closed, writes the cluster involved in the directory into the corresponding position of the first optical disc image; If the first optical disc mirror system reports that there is no free space abnormality during the writing process, the directory will be created in the second optical disc image; when the second optical disc image creates a directory, the directory will be created in the second optical disc image first. All the pre-order directories in the absolute path of , and then create themselves, and finally when the directory is closed, write all the updated clusters into the position corresponding to the second CD image; When the user writes a file, the pre-order directory information in the absolute path of the file is created until the root directory; after the pre-order directory is created, the file metadata is created, and the file data is started to be written; in the process of creating the directory, a disc occurs When the file system reports an exception of no free space, the directory will be created to the next CD; During the file writing process, when the first optical disc mirror system reports that there is no free space abnormality; select the second optical disc mirror image as the carrier for subsequent data storage, and obtain the ID of the second optical disc mirror image; Then detect the remaining number of clusters in the first optical disc image, if the actual number of remaining free clusters is greater than a threshold; create a first identification file in the first optical disc image, the first identification file name is composed of the original file name and a digital mark, the first identification file The content of the file includes the ID of the second optical disc image where the subsequent data content of the file is recorded; in the second optical disc image, recreate the pre-directory in the absolute path of the file, and then create a second identification file, the second identification file name It is composed of the original file name and the digital mark, and the content of the second identification file includes the ID of the first optical disc image where the previous part of the file data is located; finally, the subsequent data is written; When detecting the number of remaining clusters in the first optical disc image, if the actual number of remaining clusters is less than a threshold, read out the contents of the clusters within the last threshold size of the first optical disc image and save them in the memory cache, and store them in the first optical disc image. Delete the content of these clusters, record the actual length of the current file in the file metadata; create a third identification file, the name of the third identification file is composed of the original file name and a digital mark, and the content of the third identification file includes recording the subsequent content of the file. The volume number of the second optical disc image; in the second optical disc image, re-create the pre-directory in the absolute path of the file, and then create a fourth identification file, the name of the fourth identification file is composed of the original file name and a digital mark, the first The content of the four-identification file includes the ID number of the first optical disc image; finally, the data of the clusters within the threshold size range stored in the memory and subsequent data are written in sequence.

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