An NZB file carries the extension .nzb, short for Newzbin. This offers a clue that these files are utilized in USENET newsgroups. NZB files are used to fetch parts of files, that when combined together, form one large file. The one large file might be a graphic, movie, sound file, game or program.
Newsgroups are text-based electronic bulletin boards where people congregate to discuss topics of interest or exchange files. The file-based newsgroups are separate from the discussion-based newsgroups, and are referred to as binary newsgroups. Binary newsgroups are designated for exchanging files. NZB files enter the picture when people want to exchange very large binary files that must be broken up into several pieces before they can be posted.
USENET protocols limit the size of messages that can be uploaded. To post a large file, the poster must first convert the file into a text-based format (encode it) then use a software program to compress the file and divide it into numbered pieces. A popular program for this task is WinRAR. Once the file is divided into parts, it can be uploaded to a binary newsgroup. Anyone who wants the file must download all parts, then use software to reassemble, decompress and decode the file.
Sounds simple enough, except that locating binary parts in USENET isn’t that easy. There are hundreds of binary newsgroups and each file part is posted separately. Someone who wants a file might not easily find all the pieces… or even know if a file was uploaded at all. And if it was, to which newsgroup? Making matters worse, binary files have low retention rates, meaning the average news server tends to purge binaries from the system anywhere from every few days to every few weeks.
The team of folks behind Newzbin, a site that indexes USENET binary files, was interested in solving this dilemma. They did so by creating the NZB protocol, written in Extensible Markup Language (XML). The NZB file makes finding USENET binaries a cinch.
Simply put, to search for a binary file one only has to enter a search term at a USENET indexing site like Newzbin or Newzleech. Clicking on nearly any result will produce a list of indexed messages. Click a button to generate an NZB file, and assuming you’ve installed an NZB-compliant news client, the program will automatically open the NZB. The NZB file directs the newsreader to the set of requested files, pointing to their locations in USENET. The newsreader automatically loads the message IDs into the cue from the NZB file, and download begins, hands-free!
NZB files save binary fans untold hours of searching for complete files in newsgroups. A few popular news clients that are NZB-compliant include NewsLeecher, current versions of Forte Agent, and Xnews, though there are many others. If you have been downloading binaries the hard way, you might want to pick up an NZB-compliant news client and give NZB files a try. Note however, that you should avoid uploading or downloading copyrighted materials, as this is illegal in most countries, including the United States.