A typical application of Jigdo is with its
jigdo-file utility. A user that wishes to assemble a disk image downloads a relatively very small file called imagename.jigdo. The jigdo-file utility invoked with this file as an argument then proceeds to fetch additional files from the Internet: imagename.template and a series of .deb files that are listed in the .jigdo file. It then uses the mkisofs utility to build the ISO image.
Jigdo was implemented in Debian in order to reduce the need to have many CD image mirror sites, locations with sufficient disk space and bandwidth to serve numerous 650 MB files (and in more recent times, 4.7 GB files for DVD images). Instead, Jigdo files allow mirrors to carry the regular Debian archive, where packages are not grouped together in image files and instead kept separately where they are also accessible through apt-get and still allow for the making of optical disk images.
Since the release of Fedora 9 Alpha, all future release of Fedora will provide jigdo as an alternative download method for people without bittorrent access. Also, jigdo versions of Fedora 8 discs are available as well as many others variants.
Jigdo is licensed under the GNU General Public License.