LOFI(4D) Devices LOFI(4D)

lofi - Loopback file driver

The lofi file driver exports a file as a block device, enabling system utilities such as fstyp(8), fsck(8) and mount(8) to operate on underlying file system images (including CD-ROM and FAT floppy images) contained on the block device. Reads and writes to the block device are translated to reads and writes on the exported file. See lofiadm(8) for examples.

File block device entries are contained in /dev/lofi. The /dev/rlofi file contains the character (or raw) device entries. Entries are in the form of decimal numbers and are assigned through lofiadm(8). When created, these device entries are owned by root, in group sys and have permissions of 0600. Ownership, group, and permission settings can be altered, however there may be ramifications. See lofiadm(8) for more information.

lofi devices can be compressed. See lofiadm(8) for more information.

Files exported through lofi can also be encrypted. See lofiadm(8) for details on how to specify encryption keys.


Master control device


Block device for file n


Character device for file n


32-bit driver


64-bit driver (SPARC)


64-bit driver (x86)


Driver configuration file. (Do not alter).

See attributes(7) for a description of the following attributes:

Architecture SPARC, x86
Interface Stability Committed

lofs(4FS), attributes(7), fsck(8), fstyp(8), lofiadm(8), mount(8), newfs(8)

Just as you would not directly access a disk device that has mounted file systems, you should not access a file associated with a block device except through the lofi file driver.

For compatibility purposes, a raw device is also exported with the block device. (For example, newfs(8)).

November 25, 2008 OmniOS