This article introduces Jigdo. Jigdo word is Jigsaw Download abbreviation, meaning the puzzle download tool. This is a tool for downloading the Debian GNU / Linux disc. Jigdo is not only a practical tool for downloading large files (such as CD and DVD DV image files), which also demonstrates some of the features of DEBIAN GNU / Linux from one side.
1. Size of Debian GNU / Linux
Debian is an organization that is fully consisting of volunteers, from all over the world, including members from mainland China and Hong Kong Taiwan. These volunteers have a common interest, which is the system of the Debian GNU / Linux. Probably estimate, now Debian has about 1,000 volunteer developers, they pack the free software from all walks of life, and then pass the quality warranty, package into the Debian GNU / Linux system. Then, the system that is completely composed of free software is then sent to the user's hands through the Worldwide Debian mirror network. This Worldwide Debian mirroring network is also maintained by volunteers, and there are quite a few of them from universities, scientific research institutions, and commercial companies.
Debian supports more than a dozen computer architecture, including i386, Power PC, SPARC, S / 390, and ARM, and more. Debian supports nearly 10,000 packages in the i386 architecture, with volume exceeding 3g bytes. A complete Debian image is probably occupying more than 50g bytes of hard disk space. I can imagine that a busy debian mirror site will need more network bandwidth. Not only that, it is estimated that every 12 months, the volume of Debian will turn over. In addition, when Debian has a new version, due to the work of Debian's quality control, Debian's volume increases. Wait until Debian released a new version, the huge CD optical disc image file also initiated a new round of charge to Debian's global mirror network. Moreover, DEBIAN has recently begun to support the Debian system with a larger DVD disc image file. Since Debian's so large scale, the site of the Debian mirror network is somewhat overwhelmed. In this, the most serious impact is the distribution of CD and DVD disc image files.
2. Jigdo and Package Pool
Jigdo is developed to alleviate the huge CD and DVD disc image files to the impact caused by the Debian mirror network. Before introducing Jigdo, let's make up the composition of the Debian mirror site, there is a preliminary understanding.
The Debian mirror site is launched around the Structure of Package Pool. Package pool, it is really like a pool that carries the package. DEBIAN volunteers pack the free software packaged in the network and put it in this pool. Since then, other people can salvage the documents they need from this pool according to various rules. This pool itself is responsible for garbage collection, and the outdated package is eliminated. Package Pool is constantly performing the management of metabolism and Debian packages.
Debian is the best APT-GET upgrade tool that the user is proud, thanks to the Package Pool structure. Recently, the release of DEBIAN's new version has also begun to surround the package pool. It is indeed that Package Pool is the most important ring in the infrastructure of Debian. Each debian mirror site is at least a complete portion of the package pool, such as that of all I386 architectures. On the other hand, many mirrored sites are reluctant to mirrors them due to the huge volume of the CD optical disc image file, and the huge network bandwidth resources you want to consume. The protagonist of our story Jigdo will appear at this time.
Jigdo generates an index for each disc image file. This index file is like a fishing hook on the Package Pool fishing in Debian, hooks a package. You need to download the user of the CD CD image file, just run Jigdo, tell it the location of the index file, Jigdo will automatically catch the required packages from the package pool, then on the user's computer, put them to make what they need CD disc image file. In this way, the Debian's mirror site is no longer a mirroring for the Debian's CD CD image file. They only need to be a complete part of the package pool, such as that, including the all packages of the i386 architecture, doing Mirror is ok. It can be said that Jigdo mitigates the pressure of the mirror network that distributes the DEBIAN's CD disc image file as a mirror network of DEBIAN.
On the other hand, due to the support of Jigdo, Debian can now publish more CD disc image files. Because I publish a disc image file, it is actually equal to the release of a new Jigdo index file.
3. Jigdo is very simple to use
Jigdo can run on Linux and Windows. Say much above, let's take a look at Jigdo how to use it.
The first step is to confirm that you have a good working CD burner. ;) In addition, you also need a lot of hard disk space. Due to Jigdo's good design, you can only need to let the free space of the next CD disc image file, with a larger than 650m bytes. Jigdo downloads it from the demand package from Debian, will write it to the CD CD image file, then remove this package, then download the next package, so that effectively uses Hard disk space. So you don't have to worry, because Jigdo downloads the package while downloading the ISO file, you will waste how much hard disk space.
The second step is to Jigdo's home page (
Http://home.in.tum.de/~atterer/jigdo/) Download Jigdo's software. Of course, if you want to run Jigdo on Windows, you have to download Jigdo's Windows version. This software is small, less than 1M bytes. After downloading, you can run the zip package and you don't need to compile.
Step 3, run Jigdo-Lite this program, it will ask you to have a .jigdo file, this is the index it wants. If you are preparing to download the latest version of the CD disc image file for Debian, you can come from here (
http://us.cdimage.debian.org/jigdo-area/current/jigdo/ Gets a .jigdo index file for this CD disc image file. Then, then there is no special thing to do. If everything goes well, you can wait for the download, you can engrave. You see, from the user's point of view, Jigdo is very simple, right? Moreover, Jigdo fully utilizes Debian's mirrored network around the world. In the past, a CD disc image file can only be downloaded slowly from one site. Now, Jigdo splits a huge image file into many small packages, and can download from multiple mirror sites close to the user. In this way, the download speed has also increased a lot.
4. Jigdo-file
The Jigdo software package mainly includes three tools, let's introduce these three tools one by one. The first is Jigdo-file, which is to use the site administrator to scan a CD optical disk image file to generate a corresponding .jigdo index file. Jigdo-file not only handles Debian's CD CD image file, but it can also handle any website administrators need to split the large files downloaded. For example, a large Divx movie file, or a huge zip compression package. Jigdo-file In order to handle this big file, Jigdo-file needs to know where the part of this big file is. Below we use an example.
Suppose we put all the files that need to be backed up in / pub / project / snapshot. Then, we engrave all the contents of this directory into an ISO9660 format CD disc image file. Next, we need to let everyone download this ISO file so that more free software developers on the Internet understand our freedom project progress. Suppose we have many supporters as our mirror website, they already mirror's / pub / project / snapshot directory on our primary station, but they don't want to download a ISO file from us because their bandwidth and hard disk resources It is very limited. So how do we use Jigdo?
We only need to run Jigdo-file, tell it, we have to handle Snapshot.iso, which is from the file below / pub / project / snapshot directory. In this way, Jigdo-file will generate a .jigdo index. Our mirror website only needs Mirror this small index file. This will later, when the user needs to download this ISO file, it can download these independent small files from the close mirror site, and set them into a CD disc image file on their machine.
So, if we don't have a disc image file in an ISO9660 format, what should I do if I have a huge DivX movie file? We can use the split command to split a large file into a number of small files. About the split command, you can see its Man Page. After this, your mirror site can only mirror these small files generated by splits. But for users, they can also download complete DivX files from your mirror site.
With regard to jigdo-file command line option, we are not introduced here, its manual (
Http://home.in.tum.de/~atterer/jigdo/jigdo-file.html
) Is an authoritative reference.
The final explanation of Jigdo-file, which is Jigdo-File generated. This is the template used by Jigdo to assemble a large file from many small files. There may be some contents that are not included in any small file, these contents are placed in the template in the Template in any small file. 5. Jigdo-Lite
Jigdo-Lite is a tool for users to download many small files and then set them into a big file into a tool. Its usage we have already spent it in front. Users can tell it where to find one .jigdo index is ok. Everything left will give it to it. Until the last user gets the complete big file you want, such as a CD disc image file, or a Divx movie file, etc.
6. Jigdo-mirror
Jigdo-mirror is the tool used by mirror site administrators. Used to put many small files Mirror from the primary site. The file that needs to be mirrored is .jigdo index file, .Template template file, and all splitting independent small documents. Jigdo-mirror also has some additional maintenance work, so it is best to use Jigdo-mirror to make mirrors, which is convenient. For the command line options for jigdo-mirror, please refer to Jigdo-mirror manual (
http://home.in.tum.de/ ~ atterer / jigdo / jigdo-mirror.html). We will not say more here.
7. Conclusion
Jigdo has a good design that makes it possible to have many additional purposes. For example, you can update a CD optical disk image file. Debian has the latest beta CD image files every day to download by Jigdo. With Jigdo, you can do so big files without having every time you start. Because daily image files are updated on the basis of the previous day's image file, you can use Jigdo to update the image file downloaded on the previous day on the previous day using Jigdo. This greatly saves network bandwidth. From the administrator, he or she can update the CD disc image file more frequently. Because, for example, if there is a Debian Package Pool mirror, a new CD disc image file is issued, which is equivalent to put a new .jigdo index file on the mirror network.
Reference
Marked the world map of Debian Developer's approximate location:
Http://www.debian.org/devel/developers.loc Map on each red dot represents a debian volunteer.
Chart on the size of Debian:
http://ftp-master.debian.org/~mmagallo/
About Debian GNU / Linux's primary site:
http://www.debian.org/cd/
DEBIAN's latest version of the Jigdo index of the CD CD image file:
http://us.cdimage.debian.org/jigdo-...ent/jigdo/i386/
Jigdo's Homepage:
http://home.in.tum.de/~atterer/jigdo/
About author
Zhao Wei, freelancer. I have made a debian volunteer for a year. Welcome to pass
Zhaoway@public1.ptt.js.cn Contact him. His network diary is located
Http://www.advogato.org/person/zhaow/ The above is listed in other articles on the network, you are welcome to criticize advice!
