Binary newsgroups
While newsgroups were not created with the intention of distributing binary files, they
have proven to be quite effective for this. Because of the way they work, a file uploaded
once will be spread and can then be downloaded by an unlimited number of users. More
useful is that every user is drawing on the bandwidth of his or her own news server. This
means that unlike P2P
technology, the user's download speed is under his or her own control, as opposed to under
the willingness of other people to share files. In fact, this is another benefit of
newsgroups: it is usually not expected that users share. If every user makes uploads then
the servers would be flooded; thus it is acceptable and often encouraged for users to just
leech.
There were originally a number of obstacles to the transmission of binary files over
Usenet. First, Usenet was designed with the transmission of text in mind. Consequently,
for a long period of time, it was impossible to send binary data as it was. So, a
workaround, Uuencode (and later on Base64 and yEnc), was developed which mapped the binary
data from the files to be transmitted (e.g. sound or video files) to text characters which
would survive transmission over Usenet. At the receiver's end, the data needed to be
decoded by the user's news client. Additionally, there
was a limit on the size of individual posts such that large files could not be sent as
single posts. To get around this, Newsreaders were developed which were able to split long
files into several posts. Intelligent newsreaders at the other end could then
automatically group such split files into single files, allowing the user to easily
retrieve the file. These advances have meant that Usenet is used to send and receive many terabytes
of files per day.
There are two main issues that pose problems for transmitting binary files over
newsgroups. The first is completion rates and the other is retention rates.
The business of premium news servers is generated primarily on
their ability to offer superior completion and retention rates, as well as their ability
to offer very fast connections to users. Completion rates are significant when users wish
to download large files that are split into pieces; if any one piece is missing, it is
impossible to successfully download and reassemble the desired file. To work around the
problem, a redundancy scheme known as PAR is commonly used.
A number of websites exist for the purpose of keeping an index of the files posted to
binary newsgroups.
This article does not cite any references or sources.
