Linux cyclic device/dev/loop

Linux cyclic device/dev/loop (or vnd (vnode disk) or lofi (Cyclic file Interface) is a pseudo device, this type of device allows files to be accessed as Block devices. Before use, the cyclic device must be associated with files on the existing file system. This association provides you with an application interface that allows you to use a file as a special block file (see the device file system. Therefore, if a file contains a complete file system, the file can be mounted as a disk device. These device files are often used for CDs or Disk Images (IOS and IMG ). By means of cyclic mounting, you can mount the files containing the file system so that the files in the file system can be accessed. These files will appear in the mount point directory. To mount a file containing a file system in a directory: 1. use a loop device (/dev/loop) to connect to the file (use the losetup command) 2. mount the cyclic device to a directory (run the mount command). For example, there is a file sample containing the file system. img,/mnt/point is the directory, if you set sample. to mount img to/mnt/point, run the following command [plain] losetup/dev/loop0 sample. img mount/dev/loop0/mnt/point # You can use a mount command to replace the above two commands mount-o loop sample. img/mnt/point # uninstall umount/mnt/point # view all loop devices associated with the file # losetup-a losetup-d/dev/loop0