[ Huaqiang Security Network News ] Everyone knows that video recording technology in the DVR, the video function is linked with many other functions, such as playback function, network function, backup function, etc., so what kind of video recording technology is directly related to The performance and hard drive failure rate of the entire DVR. Video recording technology is divided into two aspects: 1) What kind of file system is used, which is usually related to the operating system used, and it is not easy to choose independently; 2) How to apply the system to the advantage of the file system under the premise of the selected file system While avoiding its weaknesses, it affects the entire system. 
At present, PC-type DVRs are generally based on Windows systems, and the file system is generally NTFS or FAT32; the file system used by the embedded DVR has a close relationship with the embedded control system selected by the manufacturer. At present, embedded operating systems used in embedded DVRs include pSOS, Embedded Linux, vxWorks, etc., and the file systems used are more types, such as MS-DOS compatible file systems, UNIX compatible file systems, and Windows compatible file systems. There are also various proprietary file systems and so on. Which file system is selected as the file system in the embedded DVR depends on many factors, such as the company's research and development capabilities, financial resources, and the characteristics of the file system itself. It should be said that the choice of any file system will not hinder the implementation of the recording function in the embedded DVR. Some companies even organize their own file systems to meet their needs. Of course, we do not agree with this, because it may take a long time to extend the time to market. In addition, this approach does not conform to modern society. The trend of division of labor is becoming more and more detailed and more professional, and it is difficult to be as reliable as the file system introduced by professional software vendors.
Once the file system is selected, the platform available for developers to develop is determined. The fairness of the design of the video module in the application system of each embedded DVR manufacturer directly determines the performance of the embedded DVR after it is introduced to the market. For example, some manufacturers use the method of deleting old files to achieve the purpose of recurrent video recording. In order to make the file deletion time as short as possible, a video stream file is generated every minute. Other manufacturers use one file per hour to record. A common weakness of these approaches is that long-term operation of the embedded DVR is not guaranteed. Since the bit rate change of the output of the compression chip is relatively large, the size of the files generated every minute and every hour is different, and the performance is very different. After a long time of operation, the hard disk is full of fragments. Therefore, the system operation efficiency drops sharply. This is why some embedded DVRs on the market have performed well in the initial installation, but after a while, the phenomenon of losing data and bad hard disks is easy. In order to solve this problem, some companies have proposed disk pre-allocation technology to ensure that debris is never generated during the hard disk reincarnation process.
The file system manages the disk. There is a set of file retrieval mechanism consisting of a linked list, including the FAT table and the directory area. If the FAT table or directory area is being written, the FAT table sector or directory sector is destroyed. This will result in the loss of a set of disk files. During the use of the hard disk recorder, the hard disk is written almost continuously. If it is abnormally shut down, the probability of causing the FAT table sector or directory sector to be destroyed is very high, which is why the number of abnormal shutdowns is much higher, regardless of the PC type. DVRs or embedded DVRs often fail to find a document. In order to solve this problem, DVR vendors have proposed FAT table and directory area freezing technology to ensure that the FAT table and directory area will not be destroyed during the abnormal shutdown process.
At the same time, the current small-size hard disk, also known as the warm disk (invented by IBM's special group in the Winchester building, called Winchester hard disk, referred to as the warm disk, is now called hard disk, non-Wenches The technical hard disk is almost no), it is a mechanical structure, there are two motors, one is a spindle motor, and the other is a head seek motor (currently almost all use voice coil motors). In a DVR, there are usually multiple hard disks. When recording, multi-channel images should be remembered as much as possible on one hard disk, so that other hard disk spindle motors can stop rotating, which can extend the life of the hard disk and reduce the work of the hard disk recorder. Consumption (the power consumption of the hard disk in the sleep state is about 1/10 of that under normal operation), which is called hard disk sleep technology. Based on the hard disk sleep technology, a low seek technology is proposed, which can further improve the performance of the hard disk recorder and extend the life of the hard disk. In view of the gradual damage and the related problems of the magnetic disk of the hard disk, a hard disk failure warning technology is proposed.
Once the file system is selected, the platform available for developers to develop is determined. The fairness of the design of the video module in the application system of each embedded DVR manufacturer directly determines the performance of the embedded DVR after it is introduced to the market. For example, some manufacturers use the method of deleting old files to achieve the purpose of recurrent video recording. In order to make the file deletion time as short as possible, a video stream file is generated every minute. Other manufacturers use one file per hour to record. A common weakness of these approaches is that long-term operation of the embedded DVR is not guaranteed. Since the bit rate change of the output of the compression chip is relatively large, the size of the files generated every minute and every hour is different, and the performance is very different. After a long time of operation, the hard disk is full of fragments. Therefore, the system operation efficiency drops sharply. This is why some embedded DVRs on the market have performed well in the initial installation, but after a while, the phenomenon of losing data and bad hard disks is easy. In order to solve this problem, some companies have proposed disk pre-allocation technology to ensure that debris is never generated during the hard disk reincarnation process.
The file system manages the disk. There is a set of file retrieval mechanism consisting of a linked list, including the FAT table and the directory area. If the FAT table or directory area is being written, the FAT table sector or directory sector is destroyed. This will result in the loss of a set of disk files. During the use of the hard disk recorder, the hard disk is written almost continuously. If it is abnormally shut down, the probability of causing the FAT table sector or directory sector to be destroyed is very high, which is why the number of abnormal shutdowns is much higher, regardless of the PC type. DVRs or embedded DVRs often fail to find a document. In order to solve this problem, DVR vendors have proposed FAT table and directory area freezing technology to ensure that the FAT table and directory area will not be destroyed during the abnormal shutdown process.
At the same time, the current small-size hard disk, also known as the warm disk (invented by IBM's special group in the Winchester building, called Winchester hard disk, referred to as the warm disk, is now called hard disk, non-Wenches The technical hard disk is almost no), it is a mechanical structure, there are two motors, one is a spindle motor, and the other is a head seek motor (currently almost all use voice coil motors). In a DVR, there are usually multiple hard disks. When recording, multi-channel images should be remembered as much as possible on one hard disk, so that other hard disk spindle motors can stop rotating, which can extend the life of the hard disk and reduce the work of the hard disk recorder. Consumption (the power consumption of the hard disk in the sleep state is about 1/10 of that under normal operation), which is called hard disk sleep technology. Based on the hard disk sleep technology, a low seek technology is proposed, which can further improve the performance of the hard disk recorder and extend the life of the hard disk. In view of the gradual damage and the related problems of the magnetic disk of the hard disk, a hard disk failure warning technology is proposed.
Massage Bathtub
Massage Bathtub,stand alone bath,freestanding jacuzzi tub,freestanding whirlpool tub,modern freestanding bath
Guangzhou Aijingsi Sanitary Products Co.,Ltd , https://www.hottubdesign.com