Cloop

Introduction

Cloop, is a [Kernel (computers)] [module] to add support for [filesystem-independent,] transparently decompressed, read-only, block devices.

Where to download

[1]

Use version 1.xx if you have a 2.4 kernel, or version 2.xx for 2.6 kernel. Versions 0.xx are too old, probably won't work well.

Installation

make KERNEL_DIR=/path/to/linux-kernel/sources

Issue these commands as root

mkdir -p /lib/modules/misc && cp cloop.o /lib/modules/misc/
depmod -a
mknod /dev/cloop b 240 0

Usage

Creating a compressed image:

create_compressed_fs image blocksize > image.cloop_compressed

Where blocksize must be a multiple of 512 bytes. Make sure you have enough swap to hold the entire compressed image in virtual memory!

The command may also be used in Linux command line pipe sequences. Use "-" as the image filename. The dash, "-" will cause the command to read data from stdin, as in

mkisofs -r datadir | create_compressed_fs - 65536 > datadir.iso.compressed

Mounting a compressed image (see above for device creation):

insmod cloop.o file=/path/to/compressed/image

mount -o ro -t whatever /dev/cloop /mnt/compressed