DownloadMail: richard ätt 2009.atterer.net
Last change: 2009-02-26
Jigsaw Download, or short jigdo, is a tool designed to ease the distribution of very large files over the internet, for example CD or DVD images. Its aim is to make downloading the images as easy for users as a click on a direct download link in a browser, while avoiding all the problems that server administrators have with hosting such large files.
Article about jigdo on heise.de (c't-Magazin; German)
jigdo is Free Software, distributable under the GNU GPL.
Download
Also available for Debian and Fedora Core jigdo-lite 0.7.2 for Windows, 1773 kB
This version is capable of creating DVD-sized images on NTFS partitions (FAT32 only supports sizes up to 4 GB). In case you use WinZip, click on "Extract" and select "Use folder names", don't just drag the files to a directory.
(Windows 98/ME users, try the older 0.7.1a version - 0.7.2 will not work for you due to a small problem.) jigdo-lite 0.7.1 for Solaris, 378 kB (statically linked binaries for Sparc) jigdo 0.7.3 source code, 630 kB External sources of jigdo binaries: RPMSeek, RPMFind, Mac OS X (Fink), FreeBSD, IRIX Changelog - what is new in this version?
Help
Subscribe to jigdo-user, browse the archive or send mail directly to jigdo-user ätt lists.berlios.de.
The mailing list is public - your mails will be archived, and it is not guaranteed that someone won't abuse the archive and send you spam. Documentation: The Debian CD FAQ is not directly related to jigdo, but worth checking if you have questions regarding the images you downloaded using jigdo. Debian-CD mailing list: Discussion about problems with the Debian CD images.
Subscribe to debian-cd, browse the archive or send mail directly to debian-cd ätt lists.debian.org. This mailing list is also public.
jigdoWhy is it needed?
jigdo was inspired by the problems that Debian Linux had with the distribution of its CD images. Debian is a 100% volunteer-driven organization which depends on donations to finance its infrastructure. For this reason, it also doesn't own any of the 300 servers around the world on which the distribution is mirrored.
For some time, the size of Debian has been a problem - Debian supports 11 different processor architectures, more than any other Linux distribution, and for every single one of these architectures, there are more than 10000 software packages - again more than any other distro. Today, a full Debian mirror needs roughly 100 GB of disc space!
Debian also offers the distribution in the form of CD images (and more recently DVD images). If these images were distributed as full .iso images on the mirrors, the size of a Debian mirror would double to 200 GB (or even triple to 300 GB if there were also DVD images) - nobody is prepared to mirror such a huge amount of data!
jigdo solves this problem by not requiring that the full image be stored on the servers. Instead, it can download the individual files from a normal Debian mirror and only assemble the image on the user's machine. Additionally, it can also do other useful things like helping with the mirror selection and upgrading images.
How does it work?
When someone has produced a large file they wish to distribute (for example, a CD image), they process this file with the jigdo-file tool. Among other things, jigdo-file creates a file with a .jigdo extension. To download the original file, a user only needs to tell the jigdo-lite download tool the URL of the jigdo file, it will extract all the necessary information and perform the download, fetching the data in many small pieces, possibly from several different servers.
So far, this is not exciting; there are already several other programs which allow you to split and reassemble large files, or which make their download easier. Also, at the moment only the shell script jigdo-lite can be used for downloading - the final jigdo download manager shown below will be much more comfortable to use.
![[Screenshot]](http://mowser.com/img?url=http%3A%2F%2Fatterer.net%2Fjigdo%2Fjigdo-gui.gif)
The jigdo download tool (under development - not usable at the moment)
However, jigdo's approach is unique due to the way it identifies the small pieces that the large file consists of: For instance, if the file is a CD image, the individual files on the CD are contained somewhere within the image file. jigdo-file is capable of finding these files, so if copies of the individual files on the CD are stored separately on the server, jigdo-lite can be made to download these files one by one, and assemble the CD image on the fly on the user's computer. This scheme has several advantages:
If you have read this far, you may be confused now, asking yourself what jigdo does and doesn't do. :-) It seems that the jigdo concept is a bit difficult to grasp at first. If you're still interested, have a look at the respective section of the HOWTO and at the Examples section of the jigdo-file manual.
Further jigdo resources
(Substitute the correct date - the date the broken .jigdo file was made.)
Old and current releases: 0.5.0, 0.5.1, 0.5.2, 0.5.3, 0.6.0, 0.6.1, 0.6.2/bin, 0.6.3/bin, 0.6.4/bin, 0.6.5/bin, 0.6.6/bin, 0.6.7/bin/solaris, 0.6.8/bin/solaris/win, 0.6.9/bin/solaris/win, 0.7.0/bin/win, 0.7.1/bin/solaris/win, 0.7.2/bin/win, 0.7.3/bin, prereleases
Documentation for jigdo-file, the tool for low-level processing of .jigdo/.template files. There is also a more technical introduction to how jigdo works. Documentation for jigdo-lite, a shell script which uses jigdo-file to reassemble images. It is intended to fill the gap until the real jigdo GUI application is usable. Documentation for jigdo-mirror, a shell script which Debian mirror maintainers can use for efficient mirroring of Debian CD images offered as .jigdo files. jigdo project page at BerliOS. Thanks to this non-commercial SourceForge alternative for its services!To top - Unless noted otherwise, all graphics, programs and text © Copyright 2009 Richard Atterer. All trademarks are the property of their respective owners.
