Loop device

On Unix-like operating systems, like Linux or BSD (Berkeley Software Distribution), a loop device is a regular file or device that is mounted as a file system. It may be thought of as a "pseudo device" because the operating system kernel treats the file's contents as a block device. For example, an ISO file containing internal structure details of files and directories may be mounted as a loop device, and accessed by the operating system, like a physical disk partition.

In Linux, the losetup command can manually set up and control loop devices. More commonly, the mount command may be used with the -o loop option, e.g.:

mount -o image.iso /mnt/myimage

For more information, see mounting loop devices in Linux.

Linux kernel, Loop, Operating system terms, Special file