WARNING
=======

The default loop device major number has changed from 12 to 28. Please make
sure your old /dev/loop* devices are removed and new ones created as shown
below.

Loop devices, version 3.3
=======================

The modularized loop device may be installed at a block device of your
choice without recompilation (see NEWS file). I added this because the loop
device is not officially registered and it would be nice to easily reload it
on another device if the major gets allocted.

Loop devices, version 2
=======================

Loop devices can be used to mount regular files, to put more than one
file system on a disk partition and to provide transparent data
encryption.

Note: This implementation differs from my old loop devices that are
      also found in some distributions of SLS.

All this code is covered by the General Public License.

Creating loop devices
---------------------

Create the device entries in /dev:

  for n in 0 1 2 3 4 5 6 7; do mknod /dev/loop$n b 28 $n; done

Installation
------------
Do one of the following depending on whether the loadable modules
or a kernel patch are required. However because the block driver symbols
are not in the kernel syms, even the loadable driver requires that a small
patch be applied to your kernel source. The module patch is the preferred
method of using the driver and will always have the most up to date fixes.

Applying the Kernel patch
-------------------------
Apply the kernel patch to your 1.1.16 kernel source:

      (cd /usr/src/linux; patch -s) < patches/lo.patch 
  
Patch for the Loadable driver
-----------------------------
Apply the ksyms patch to your 1.1.16 kernel source:

If you are using a kernel prior to version 1.1.23 then do:

      (cd /usr/src/linux; patch -s) < module/lo.patch-pre-1.1.23

otherwise for the new module code, use

      (cd /usr/src/linux; patch -s) < module/lo.patch

In the latter case you MUST also have the new module utilities (insmod, rmmod
etc..) from nic.funet.fi /pub/OS/Linux/PEOPLE/Linus/v1.1

DES Encryption
--------------

If you want to use DES encryption, download the DES module and add it:

  cd /usr/src/linux
  tar xvfz des.1.tar.gz
  touch include/linux/des.h kernel/des.c

Rebuild the kernel:
-------------------

  make depend
  make		# or something like that

The loop.o module:
------------------

If you decide to use the loop loadable module you need to compile the object:

  cd module
  make

Migration
---------

Version 1 (and later) of the loop devices uses a slightly different wrapper
algorithm for DES than version 0. In the unlikely event that you have some
old ecrypted files, you have to convert them with the (untested) utility
cvdes before they can be used with version 1 and later. (See the man page
for details.)

Usage
-----

Is documented in the accompanying losetup man page, or read mount/README.

Authors
-------

Original author: Theodore Ts'o <tytso@athena.mit.edu>
Maintainer: Werner Almesberger <almesber@bernina.ethz.ch>
DES author: Eric Young <eay@psych.psy.uq.oz.au>
Modularized and updated 28-5-94: Mitch DSouza <m.dsouza@mrc-apu.cam.ac.uk>
