CN1395246A - Method for implementing virtual image optical disk and and its system hardware structure - Google Patents

Abstract

The invention belongs to the technical field of optical disc network shared storage. It involves the realization method of the virtual image CD and its system hardware structure, including the construction of a single-device, single-level directory, and continuous distribution of the virtual image CD file system; the directory extraction of the virtual mirror CD file; marking the storage slot, according to the continuous logic The block addressing mode mirrors the physical CD disk; loads the loopback device to realize the management of the virtual mirror CD disk file by the operating system. The hardware structure of the invention can greatly improve the response speed of the system.

Description

Realization method of virtual image disc and system hardware structure

technical field

The invention belongs to the technical field of optical disc network shared storage, and in particular relates to a method for realizing a virtual image optical disc and a system hardware structure design thereof.

Background technique

Among the implementation schemes of many optical disk network shared storage systems, the mirrored optical disk server system is increasingly becoming the storage system adopted by many applications due to its large storage capacity and low unit storage cost. The so-called mirrored optical disk server system is a The network protocol and file system mirror the storage content of multiple optical discs to the server data hard disk system, which can manage multiple optical discs in a unified manner and provide users with optical disc network sharing services

Most of the current mirror disc server systems mirror disc data in the form of hard copy. The hard copy method is also called direct copy. Direct copy refers to directly saving the disc content in the data hard disk according to the built-in file system format of the server system by directly reading the disc data. on the way. The storage format of CD data in the hard disk drive depends on the built-in file system, and the general image CD server adopts the Linux operating system, and the most common file format on this operating system is the Ext2 file format at present. Like many filesystems, Ext2 is built on the premise that data is stored within files in blocks. Before using the hard drive to store data, the user must perform partition formatting on the hard drive. Formatting is a process of creating superblocks and writing file nodes. During this process, a part of the storage space on the hard drive will be occupied. When using the mirror disc server, the contents of the mirror disc can only be stored on the partitioned and formatted hard disk drive, and its storage format is also reorganized and stored on the hard drive according to the formatted file format through the operating system. Because the image CD stored on the general mirror CD server is not a standard CD file format, there are a series of problems.

1. It is difficult to guarantee safety. Although the Ext2 file system is the most widely used in Linux distributions, because the designers of Ext2 mainly consider the performance of the file system, Ext2 does not write the content of the file and the file at the same time. Relevant information, such as: permissions, owners, and creation and access times, in other words, Linux first writes the contents of the file, and then waits until it is free to write the relevant information of the file. In this way, if the system suddenly loses power after writing the file content but before writing the relevant information of the file, it may cause the file system to be in an inconsistent state. This can have serious consequences on a system with a lot of file operations.

2. The utilization efficiency of the hard disk drive is low. Since the mirror disc server adopts direct copy method to mirror disc content, and the file system adopted by the operating system is not a file format specially designed for the mirror disc server, it not only consumes disks for creating super blocks and writing file node tables when formatting hard disk space Space, and every time a directory or a file on the optical disc is copied, its corresponding file information must be recorded, resulting in a large amount of unnecessary waste of disk space, and increasing the number of addressing times and addressing time of the system.

3. The system starts slowly after an abnormal shutdown. After an abnormal shutdown (power outage, system crash), the Ext2 file system can only be loaded and used when the Ext2 file system is checked for consistency by the disk verification program e2fsck at the next startup. The time to run e2fsck depends mainly on the size of the Ext2 filesystem. It takes a long time to verify a slightly larger file system (tens of GB). If the number of files on the file system is large, the verification time will be longer. Verifying a file system of several hundred gigabytes can take an hour or more. Usually, the mirror image CD server needs to configure dozens of GB to hundreds of GB or even more hard disk space, which greatly limits the availability of the mirror CD server.

4. The data stream output is discontinuous. The mirror disc server simply copies the files and directories in the disc to the hard disk, and the storage of the contents of the disc on the hard drive is not a file system that conforms to the structure standard of the disc file system. The disadvantage of this method is that when the user accesses the mirrored disc on the server, the output of the system is not a continuous and stable disc format data stream, but a data stream that is reorganized by the operating system and randomly stored on the hard disk. For audio and video files such as VCD/DVD that require continuous and stable data stream output during real-time access, there must be defects when users access them, resulting in discontinuous data output, intermittent video and audio signals, Greatly affect the viewing effect.

Contents of the invention

The purpose of the present invention is to propose an effective method for constructing a virtual image optical disk and its system hardware structure, which can conveniently and quickly store the content on each physical optical disk according to the optical disk file system on the disk The structure standard is stored on the data hard disk of the mirrored CD server system, which shortens the system's addressing time, speeds up the system's response speed, and realizes the real CD data stream output.

A method for constructing a virtual mirror image disc according to the present invention is characterized in that it includes:

1) Construct a single-device, single-level directory, and continuously allocated virtual image disc file system on the data disk;

2) directory extraction is performed on the virtual mirror image disc file of the virtual mirror disc file system;

3) mark the storage slot on the storage space of the data disk, so as to set up a new virtual image disc record, and mirror the physical disc disc according to the continuous logical block addressing mode;

4) Loading a loopback device on the virtual image optical disk to realize the management of the virtual image optical disk by the operating system.

The method of the present invention specifically comprises the following steps:

1. First, construct a single-device, single-level directory, and continuously allocated virtual image disc file system. The data structure of the constructed file system is shown in Figure 1, including:

1). Construct the data structure of the total disk information of the data disk, including the total information of the volume identified by the disk, and the data structure including the size information of the disk, the length of the directory area, and the free space of the disk.

2).Construct the data structure of the directory area, set each data disk to be controlled by the operating system in the form of a single device, install it on an installation point of the operating system, set up a directory area on each data disk, and save the directory area The file names, starting sector numbers, file lengths, access rights, and operation time records of all virtual image discs mirrored on the data disk;

3). Construct the data structure of the file area of the said virtual image CD file system; the file area stores files one by one on the data disk in sequence, one file is a virtual image CD disk, and one file saves a mirrored the contents of the physical disc;

4). Construct the data structure of the disk free space information of each data disk in a group counting manner, and allocate or reclaim a group of continuous disk disk blocks at the same time. The data structure of the disk free space information is a two-dimensional Free space table, each record item records the first block address of each group of free disk blocks and the number of free disk blocks in this group, one record item corresponds to a row of the free space table, and each row of the free space table consists of a disk block address item and a block number.

After the virtual image disc file system is constructed, the virtual image disc file system is added to the kernel of the operating system according to the file system interface provided by the operating system.

2. In order to realize a single-device, single-level directory, and continuously stored virtual image CD file system, it is necessary to extract the directory of the virtual mirror CD file in advance.

1) Set the directory name of the Mth virtual image disc file as dir1/dir2/.../dirN, and the file name as mirrorcdm;

2) Record the system disk directory as tower. After the installation program intercepts the mirroring command and directory data sent by the server system administrator, it creates the Mth virtual mirroring CD in the system disk directory according to the mirroring order of the virtual mirroring CD. The serial number directory of the virtual image disc, the serial number of the virtual image disc is numbered from 0, and the serial number directory of the virtual image disc is recorded as cd(M-1). 1st-level directory dir1, 2nd-level directory dir2, ..., N-level directory dirN order to create the storage directory of the virtual image CD file;

3) Extraction of the file name of the virtual mirror CD: after the installation program obtains the file name mirrorcdm of the virtual mirror CD, in the directory created, create the same installation point directory mirrorcdm as the file name mirrorcdm of the virtual mirror CD /, and establish a soft link from the serial number directory /tower/cd(M-1)/ to the cdromtower/dir1/dir2/.../dirN/mirrorcdm/ directory;

4) Find the disk mirroring space of the data disk: Find the data disk with enough continuous storage space to store the content of the mirrored physical CD, and search under the installation directory of the first data disk with sufficient continuous storage space The directory where the hidden virtual image disc is located is recorded as .iso/; after finding it, create the suffix name of the virtual image disc file that can identify the format of the disc file system in this directory, mark it as iso, and the virtual image disc The disc file name is recorded as mirrorcdm.iso.

3. Marking the storage slot, mirroring the physical optical disc according to the continuous logic block addressing mode, and constructing a virtual image optical disc conforming to the actual physical optical disc file system standard in the storage slot.

1) After obtaining a section of continuous disk space enough to accommodate the content of the virtual image disc, add the occupied information of this section of disk space in the established data structure, record the starting block number and the total number of blocks occupied, Finish marking the storage slot;

2) Add the file information of the new virtual image CD in said directory area, including the file name of the virtual image CD, the initial sector number, the file length, the access authority, and the operation time record;

3) Read the data recorded on the physical disc in the system optical drive according to the continuous logical block addressing mode, start counting from the 0th sector on the physical disc, read the contents of the sectors sequentially, and follow the continuous logical block addressing mode Write to the allocated storage slot space, start writing from the first allocated sector, read and write at the same time, until the last sector of the physical disc recording data, write to the last sector of the allocated storage space ; Make all the data recorded in the physical disc be written into the continuous storage slots of the allocated storage space according to the data format stored in the disc. In this continuous storage space, the main volume description of the actual physical disc is saved. frame, ending volume description frame, directory table, directory file, and all file information and file data.

4. Load the loopback device on the said virtual image disc to realize the management of the virtual image disc by the operating system. The loopback device is a mechanism to use files to simulate block devices. Here, it is to use the virtual image disc A disk file emulates a block device. Specifically include the following steps:

1) Read information such as the initial sector number, file length, access rights, and operation time records of the virtual image CD file through the file name of the virtual image CD file;

2) Judging which optical disc file system structure standard the data format stored in the file conforms to according to the suffix name of the virtual image optical disc disc file, and outputting the file data stream according to the corresponding optical disc file system structure standard format. Since then, the construction of the virtual CD file system, the directory extraction of the virtual CD file, the establishment of the storage slot and the mirror image of the actual physical CD disk have been completed, and the management of the virtual mirror CD disk by the operating system has been realized. A virtual image disc is created.

Implementation principle of the present invention is described as follows:

To realize a high-performance image disc server, a very important technology is how to realize each image disc file in the storage space of the server in a continuous and consistent manner with the original physical disc file system structure standard according to the storage capacity provided by the disk space. storage.

Through the research, it is found that the method of mirroring the physical disc with the storage slot has good feasibility. The idea of mirroring a physical optical disc based on a storage slot is as follows: the storage space provided by a disk drive, that is, a hard drive or a disk array, is continuously divided into many parts, and each part is an independent continuous storage slot; The storage capacity of a specific physical optical disc corresponds to the storage capacity, and different storage slots correspond to different actual physical optical discs; the data stored in the physical optical disc that conforms to the optical disc file system structure standard also conforms to the optical disc file system structure It is stored in each corresponding storage slot in a standard way; by loading the virtual device driver program for each virtual image CD stored in the corresponding storage slot, the user can access and manage the virtual mirror CD.

Both the current disk interface protocol and optical drive interface protocol support continuous logical block addressing mode (Logical BlockAddress: LBA) for data read and write operations, which provides a technical basis for the realization of the idea of storage slot mirroring physical optical discs.

The present invention proposes a hardware implementation structure of a virtual mirror image CD server that adopts the above-mentioned method to realize a virtual mirror image CD disk. It is characterized in that: it comprises a PC motherboard with CPU and memory, a network card inserted into the PCI slot of the PC motherboard, a system hard disk, a system optical drive, multiple IDE hard drives, multiple SCSI hard drives, and multiple IDE interfaces. disk array, a disk array with multiple SCSI interfaces, SCSI interface cards, and the IDE bus and SCSI bus connecting each module; said system hard disk and system optical drive are connected to the IDE1 port bus of the PC motherboard, and said IDE expansion card and The SCSI interface card is connected with the PCI slot of the PC motherboard, and the disk arrays of said multiple IDE hard drives and multiple IDE interfaces are connected with the IDE2 port bus or the IDE expansion card of the PC motherboard, and the said multiple SCSI hard drives and Disk arrays with multiple SCSI interfaces are connected to the PC motherboard through SCSI interface cards.

The present invention has the following advantages:

1. Fast data response. Because the present invention adopts the method of mirroring the content of the physical optical disc in the storage slot, each time a physical optical disc is mirrored, it only needs to record the relevant information of the disc once, and there is no need to record the file information related to each file and directory on the disc multiple times , when the user accesses the same virtual image disc file, the number of seeks and the seek time of the system are greatly shortened, thereby greatly improving the data response and data stream output of the server as a whole.

2. The server recovers quickly after a power failure, and the security performance is improved. Due to the use of storage slots to manage mirrored discs, the system restarts quickly after an abnormal shutdown and does not need to go through a lengthy disk verification before it can be started; because the data stored in the disk space is in the format of a disc, it effectively prevents hackers and viruses from invading.

3. The output data flow is continuous and stable. Since the virtual image disc on the storage slot is continuously stored, and the storage format conforms to the corresponding CD-ROM disc file system standard, when a single user or multiple users access the virtual disc, the output of the server is continuous and stable. The data stream conforms to the optical disc file system structure standard, which means that when there is no network failure, the user obtains a smooth and flat data stream as if directly accessing the optical drive, eliminating the need for real-time access such as VCD/DVD. Defects in audio and video files that require output of continuous and stable data streams.

4. The storage capacity of the system has a large room for expansion. Since the system supports hard disks with SCSI interface, each SCSI card can be connected with 8 SCSI hard disks, and the storage space of 2 IDE interface hard disks can be added to the storage space of 8 SCSI hard disks.

5. The system design is economical. The hardware used in this system design scheme, including network equipment, is a common PC component, and there is no need to purchase special hardware or dedicated network facilities. Therefore, the system implementation scheme is very economical.

Description of drawings

FIG. 1 is a schematic diagram of the data structure of the virtual optical disc file system of the present invention.

Fig. 2 is a schematic diagram of the data structure of disk free space information in the virtual disk file system of the present invention.

Fig. 3 is a schematic diagram of the corresponding relationship between the storage slot, the virtual image optical disk file and the virtual image optical disk according to the present invention.

Fig. 4 is a relational diagram of the overall structure of the virtual image optical disc constructed in the present invention.

FIG. 5 is a hardware structural diagram of a virtual mirrored optical disc server for implementing a virtual mirrored optical disc in this embodiment.

FIG. 6 is a data structure diagram of the virtual image optical disc file system in this embodiment.

Detailed ways

The embodiment of the virtual image optical disc of the present invention will be described in detail below in conjunction with the accompanying drawings, and its hardware structure is shown in FIG. 5 . Including: PC motherboard with CPU and memory, network card inserted into the PCI slot of the PC motherboard, a system hard disk, a system optical drive, two IDE interface hard disks with a capacity of 30.6Gb, a SCSI hard disk with a capacity of 80Gb, and a SCSI Interface card, and the IDE bus and SCSI bus that connect each module are formed; said system hard disk and system optical drive are connected with the IDE1 port bus of PC main board, and said SCSI interface card is connected with the PCI slot of PC main board, and said The IDE hard disk is connected with the IDE2 port bus card of the PC mainboard, and the said SCSI hard disk is connected with the PC mainboard through the SCSI interface card. Note: 1Gb=10 ⁹ byte, 1Mb=10 ⁶ byte, byte: byte.

The PC motherboard of the present embodiment is the hardware platform of system operation, and all software parts such as the operating system embedded in the server and the network protocol and the installation management program run on the system hard disk connected to the IDE1 port bus of the PC motherboard, insert the PC motherboard The network card in the PCI slot is the network device required by the server to access the Internet. The system reads the CD-ROM data in the CD-ROM drive and mirrors it to the IDE hard drive connected to the IDE2 port bus of the PC motherboard or to the SCSI card and stored on a SCSI hard drive attached to the motherboard.

In this embodiment, the embedded operating system of the server adopts the Linux operating system. After the system is turned on, the operating system kernel is first started, including loading the virtual image disc file system, and then starting various service processes provided by the server, and then reading the virtual image disc. file, if there is, then load the loopback device driver to each virtual image CD file in turn, if not, then skip the step of loading the loopback device driver, and finally wait for user access or the order of the system administrator. In this embodiment, the physical optical discs used for mirroring are all discs with a capacity of 680Mb conforming to the ISO9660 optical disc file system international standard. Therefore, the size of each storage slot is 680Mb, accounting for 2656250 sectors, and each disk sector Contains 256 bytes, loads the loopback device driver and outputs the data stream in a format conforming to the ISO 9660 optical disc file system international standard.

Each IDE hard disk with a capacity of 30.6Gb (a total of 119531250 disk sectors) can store 44 pieces of 680Mb virtual image disks, and a SCSI hard disk with a capacity of 80Gb can store 117 pieces of 680Mb virtual image disks. Therefore, in this embodiment, a total of 205 virtual image disks with a size of 680 Mb can be stored.

1. Taking the main hard disk of the IDE2 port as an example, the data structure of the virtual image disc file system is shown in Figure 6 (the n value shown is 2656250 sectors occupied by a single virtual image disc in this embodiment, and the N value It is the maximum number of sectors of the total hard disk capacity (119531250), including the total information of the disk volume, the directory area (file description information area), and the file area. The contents of each part are as follows:

1. The data structure of the total disk information of the IDE hard disk, including the total volume information of the hard disk identification, including the disk size information of 30.6Gb (119531250 disk sectors), the length of the directory area (set to 44 disk sectors) , disk free space information (the disk free space information table takes up 4 disk sectors), and other data structures, and the total disk volume information takes up 10 disk sectors in total.

2. The data structure of the directory area. The installation point of the main hard disk of the IDE2 port on the operating system is /tower/cdromtower/.ftp/hda/, and a directory .iso is set up under the installation point. The length of the directory area occupies 44 disk sectors, and the image is saved in The file name, starting sector number, file length, access authority, operation time record and other attributes of each virtual image disc on the hard disk.

3. The data structure of the file area. The file area stores files one by one in sequence, and a file is a virtual mirrored optical disc, which stores the content of a mirrored physical optical disc.

4. Construct the data structure of the disk free space information of each data disk in a group counting manner, and allocate or reclaim a group of continuous disk blocks at the same time. The disk free space information table occupies 4 disk sectors, as shown in Figure 2, the data structure of the disk free space information is a two-dimensional free space table, and each entry records the address of the first block of each group of free disk blocks and the The number of free disk blocks in the group, one record item corresponds to a row of the free space table, and each row of the free space table is composed of a disk block address item and a block number.

After the construction of the virtual image disc file system is completed, the virtual image disc file system is added to the kernel of the Linux operating system according to the file system interface VFS provided by the Linux operating system.

In this embodiment, the specific steps for constructing a virtual image disc are as follows:

1. First, construct a virtual image disc file system that can be integrated into the kernel of the server's embedded operating system, with single-device, single-level directory, and continuous allocation:

1. Construct the data structure of the total disk information of the data disk, including the total volume information of the disk identification, and the data structure including the size information of the disk, the length of the directory area, and the free space of the disk.

2. Construct the data structure of the directory area. It is set that each data disk is controlled by the operating system in the form of a single device, installed on an installation point of the operating system, and a directory area is set up on each data disk, and the directory area stores all the virtual devices mirrored on the data disk. The file name, starting sector number, file length, access authority, and operation time record of the mirror image disc.

3. Construct the data structure of the file area of the said virtual image disc file system. The file area stores files one by one sequentially, one file is a virtual image CD, and one file stores the content of a mirrored physical CD.

4. Construct the data structure of the disk free space information of each data disk in a group counting manner, and allocate or reclaim a group of continuous disk blocks at the same time. As shown in Figure 2, the data structure of disk free space information is a two-dimensional free space table. Each record item records the address of the first block of each group of free disk blocks and the number of blocks in this group of free disk blocks. One record item corresponds to A row of the free space table, each row of the free space table is composed of a disk block address item and a block number.

After the virtual image disc file system is constructed, the virtual image disc file system is added to the kernel of the operating system according to the file system interface provided by the operating system.

2. In order to realize the single-device, single-level directory virtual image disc file system, it is necessary to extract the directory of the virtual image disc file in advance:

1. Set the mirror directory name of the Mth mirrored physical disc as dir1/dir2/.../dirN, and the virtual mirror disc file name as mirrorcdm;

2. Extract the directory name of the virtual image CD file according to the following method: create the serial number of the Mth virtual image CD disk according to the storage order of the virtual image CD disk under the system disk directory (record the system disk directory as tower) directory (recorded as cd(M-1)), (note: the serial number of the virtual mirror disc disc starts from 0), and at the same time, it is in order according to level 1 under the general directory of the virtual mirror disk of the virtual mirror disc server (marked as cdromtower) Directory dir1, level 2 directory dir2, ..., N level directory dirN create storage directories for virtual image disc files in sequence.

3. Extraction of the file name of the virtual image disc. After the installer obtains the file name mirrorcdm of the virtual image CD, create the installation point directory mirrorcdm/ that is the same as the file name mirrorcdm of the virtual mirror CD under the directory cdromtower/dir1/dir2/.../dirN established in the above steps, and Create a soft link from the root directory /tower/cd(M-1)/ to the cdromtower/dir1/dir2/…/dirN/mirrorcdm/ directory.

4. Find the disk image space of the data disk. Find the physical disk with enough continuous storage space to accommodate the content of this virtual image disc, and find the directory where the hidden virtual mirror disc is located under the installation directory of the first disk with sufficient continuous storage space (denoted as .iso /). After finding it, create a virtual image disc file with a suffix name that can identify the format of the optical disc file system (the mark is iso, and the virtual image disc file name is mirrorcdm.iso) in this directory.

3. After the directory extraction is completed, mark the storage slot and construct a mirror image disc in the storage slot that conforms to the actual physical disc file system standard:

1. Mark the storage slot. The so-called storage slot is a continuous storage space, and marking the storage slot is to add a use or free mark to this continuous space in the data structure of the virtual image optical disc file system. A storage slot corresponds to the file area in the virtual image optical disc file system. A file, a virtual image disc can be stored in this storage slot, and there is a one-to-one correspondence between them, as shown in FIG. 3 . According to the above steps, in the previous step, a section of continuous disk space enough to accommodate the contents of the virtual image disc was obtained. At this time, the information about the occupied disk space of this section is added to the total disk information of the data disk, and recorded The starting block number and the total number of blocks occupied complete the marking of the storage slot.

2. Add the file information of the new virtual image CD in the directory area of the data disk, including the file name of the virtual image CD, the starting sector number, the file length, access rights, operation time records, etc.

3. Read the data recorded on the physical disc in the system optical drive according to the continuous logical block addressing mode (Logical Block Address: LBA), starting from the 0th sector (note: the sector count on the physical disc starts from 0), Read the contents of the sectors sequentially, and write them into the allocated storage slot space according to the continuous logical block addressing mode, start writing from the allocated first sector, write while reading, until the data is recorded on the physical disc Write to the last sector of the allocated storage space. In this way, all the data recorded in the physical disc is completely written into the continuous storage slots of the allocated storage space according to the data format stored in the disc. In this continuous storage space, the main volume description of the actual physical disc is saved. Primary Volume Description, Terminal Volume Description, Path Table, DirectoryFile, and all file information and file data.

So far, the virtual image disc has been stored in the storage space of the server in a continuous manner that conforms to the ISO 9660 disc file system format on the original physical disc.

4. Next, construct a loopback device for the virtual image CD, so as to realize the management of the virtual image CD files by the operating system. Here, the loopback device uses the ISO 9660 file to simulate the block device, that is, uses the virtual image disc file to simulate the block device.

1. Read the starting sector number, file length, access authority, operation time record and other information of the virtual image CD file through the file name of the virtual image CD.

2. According to the suffix .iso of the virtual image disc file, it is judged that the data format stored in this file conforms to the ISO 9660 optical disc file system structure standard, and the file data stream is output according to the ISO 9660 optical disc file system structure standard format.

So far, a new virtual image CD has been completely added to the virtual CD image server. The system enters the state of waiting for the next operation command from the administrator.

The relationship between the above parts can be represented by the overall structural relationship diagram of the virtual image disc as shown in Figure 4. It can be seen that the storage slot, that is, the virtual image disc, is built on the virtual disc file system , the operating system manages the data stored on the data disk through the interface of the virtual image optical disk file system, and realizes the access to the virtual image optical disk by loading the loopback device driver.

During the generation process of the new virtual image CD, it does not affect the user's access to other virtual image CDs on the server system.

The data structure of the virtual image CD file system on other data hard disks in this embodiment and the generation process of the virtual mirror CD disk are similar to the above, with two differences. The installation point is /tower/cdromtower/.ftp/hdb/, the installation point of the SCSI hard disk is /tower/cdromtower/.ftp/sda/, and the other is the specific value in the data structure of the virtual image disc file system. , as long as the value of the corresponding IDE2 port main hard disk is replaced with the new hard disk data value.

The physical CD used in this embodiment is a CD that meets the ISO 9660 international standard. If you use CDs in other formats (such as: UDF, Joliet, Romeo, etc.), you can also implement a virtual image CD in the same way. That is, the storage slot is used to mirror the physical optical disk and the loopback device driver is loaded to realize the output file data stream conforming to the structure standard of the original physical optical disk file system.

Claims (6)

1. An implementation method for constructing a virtual image disc, comprising the following steps: 1) Construct a single-device, single-level directory, and continuously allocated virtual image disc file system on the data disk; 2) directory extraction is performed on the virtual mirror image disc file of the virtual mirror disc file system; 3) mark the storage slot on the storage space of the data disk, so as to set up a new virtual image disc record, and mirror the physical disc disc according to the continuous logical block addressing mode; 4) Loading a loopback device on the virtual image optical disk to realize the management of the virtual image optical disk by the operating system. 2. The implementation method of constructing a virtual mirror image disc as claimed in claim 1, wherein said method of constructing a single device, a single-level directory, and a continuously distributed virtual mirror disc file system specifically includes the following steps: 1). Construct the data structure of the disk total information of the data disk, including the disk volume total information of the disk identification, including the disk size information, the length of the directory area, and the data structure of the disk free space information; 2).Construct the data structure of the directory area, set each data disk to be controlled by the operating system in the form of a single device, install it on an installation point of the operating system, set up a directory area on each data disk, and save the directory area The file names, starting sector numbers, file lengths, access rights, and operation time records of all virtual image discs mirrored on the data disk; 3). Construct the data structure of the file area of the said virtual image CD file system; the file area stores files one by one on the data disk in sequence, one file is a virtual image CD disk, and one file saves a mirrored the contents of the physical disc; 4). Construct the data structure of the disk free space information of each data disk in a group counting manner, and allocate or reclaim a group of continuous disk disk blocks at the same time. The data structure of the disk free space information is a two-dimensional Free space table, each record item records the first block address of each group of free disk blocks and the number of free disk blocks in this group, one record item corresponds to a row of the free space table, and each row of the free space table consists of a disk block address item and a block number. 3. The realization method of constructing a virtual mirror image CD as claimed in claim 1, wherein said method for extracting a directory of a virtual mirror image CD file specifically includes the following steps: 1). Set the mirror directory name of the Mth virtual mirror disc as dir1/dir2/.../dirN, and the file name as mirrorcdm; 2). Record the system disk directory as tower. After the installation program intercepts the image command and directory data sent by the server system administrator, it creates the Mth virtual image CD in the system disk directory according to the mirroring sequence of the virtual image CD. The serial number directory of the virtual mirror disc, the serial number of the virtual mirror disc is numbered from 0, the serial number directory of the virtual mirror disc is recorded as cd(M-1), and at the same time, it is in the virtual mirror disc general directory cdromtower of the virtual mirror disc server. According to the order of the first-level directory dir1, the second-level directory dir2,..., the order of the N-level directory dirN, create a storage directory for the virtual image CD file; 3). Extraction of the file name of the virtual mirror CD: after the installer obtains the file name mirrorcdm of the virtual mirror CD, in the directory created, create the same installation point directory as the file name mirrorcdm of the virtual mirror CD mirrorcdm/, and establish a soft link from the serial number directory /tower/cd(M-1)/ to the cdromtower/dir1/dir2/.../dirN/mirrorcdm/ directory; 4). Find the disk mirroring space of the data disk: Find the data disk with enough continuous storage space to store the content of the mirrored physical CD, and find the first data disk with sufficient continuous storage space under the installation directory Find the directory where the hidden virtual image disc is located, record it as .iso/; after finding it, create the suffix name of the virtual image disc file that can identify the format of the disc file system in this directory, mark it as iso, the virtual image The CD-ROM file name is recorded as mirrorcdm.iso. 4. The method for constructing a virtual mirrored optical disc as claimed in claim 3, wherein said method of marking a storage slot and mirroring a physical optical disc in a continuous logical block addressing mode specifically comprises the following steps: 1). After obtaining a section of continuous disk space enough to accommodate the content of the virtual image disc, add information about the occupied disk space in the established data structure, and record the starting block number and the total number of blocks occupied , complete the marking of the storage slot; 2). Add the file information of the new virtual image CD in the said directory area, including the file name of the virtual image CD, the initial sector number, the file length, the access authority, and the operation time record; 3). Read the data recorded on the physical disc in the system CD-ROM drive according to the continuous logical block addressing mode, start counting from the 0th sector on the physical disc, read the contents of the sectors sequentially, and address according to the continuous logical block Write in the allocated storage slot space, start writing from the first allocated sector, read and write at the same time, until the last sector of the physical disc recording data, write to the last sector of the allocated storage space area; make all the data recorded in the physical disc be written into the continuous storage slots of the allocated storage space according to the data format stored in the disc, and the main volume of the actual physical disc is saved in this continuous storage space Descriptor sheet, ending volume description sheet, table of contents, directory file, and all file information and file data. 5. The realization method of constructing a virtual mirror image disc as claimed in claim 4, characterized in that, the said virtual mirror disc is loaded with a loopback device to realize the management of the virtual mirror disc by the operating system, specifically Include the following steps; 1). Read the starting sector number, file length, access authority, operation time record and other information of the virtual image CD file through the file name of the virtual image CD; 2). According to the suffix name of the virtual image disc file, it is judged which disc file system structure standard the data format stored in the file conforms to, and the file data stream is output according to the corresponding disc file system structure standard format. 6. A virtual image disc server system hardware structure for storing and managing virtual image discs as claimed in claim 1, characterized in that: it includes a PC motherboard with a CPU and internal memory, inserted into the PCI slot of the PC motherboard A network card in the system, a system hard disk, a system CD-ROM drive, multiple IDE hard drives, multiple SCSI hard drives, multiple IDE interface disk arrays, multiple SCSI interface disk arrays, SCSI interface cards, and IDE connected to each module Bus and SCSI bus; said system hard disk and system optical drive are connected with the IDE1 port bus of PC main board, said IDE expansion card is connected with the PCI slot of PC main board with SCSI interface card, said multiple IDE hard drives and The disk arrays with multiple IDE interfaces are connected with the IDE2 port bus or IDE expansion card of the PC mainboard, and the multiple SCSI hard disk drives and the disk arrays with multiple SCSI interfaces are connected with the PC mainboard through the SCSI interface card.

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