HARLEY HAHN'S USENET CENTER
File Sharing Tutorial
The amount of data that must be stored to provide Usenet's file sharing service is enormous, and most Usenet providers never throw anything away. In other words, they save — permanently — all the data that is uploaded to Usenet. This concept is called RETENTION and is measured in days.
For example, if a provider offers 1,000 days of retention, it means you can access anything that has been posted to Usenet in the last 1,000 days. The following table shows various Usenet providers, along with their retention of binary files. Notice they all offer close to three years (1095 days) of binary retention. Moreover, retention of text files is considerably longer, because text files require much less disk storage than do binary files.
As we discussed in the previous section, most of the data within Usenet consists of binary files that are uploaded so as to be available for sharing. How much data is this? As I write this, the amount of data uploaded to Usenet is in the order of 9 terabytes a day. This means that for a Usenet provider to retain everything that is posted to Usenet, they must store over 9 trillion bytes of new data every day! Moreover, the total amount of data — about 2.5 years worth — must be available quickly, at all times, to a vast number of simultaneous users.
To provide such service, Commercial Usenet providers build their systems around SERVER FARMS: complex data-storage systems consisting of a great many special-purpose computers designed to act as file servers. Server farms are generally very large, very fast, and very reliable. Usenet server farms are designed to support high-speed uploading and downloading for a large number of users at the same time. Indeed, the largest Usenet providers actually maintain several server farms, each of which consists of many computers and disk drives working together as a single, immense entity.
In order to appreciate just how remarkable the modern Usenet system is, let's compare it to BitTorrent, another very popular file-sharing system.
Like other Internet-based systems, BitTorrent is a client-server system. There is, however, a big difference between Usenet and BitTorrent. When you use Usenet, your client program (that is, your newsreader) connects to a large, centralized news server, maintained by an Usenet provider. BitTorrent, however, is designed to not use a central server. Instead, BitTorrent users share data by connecting directly to other users's computers.
In other words, where Usenet users upload and download files from a central server, BitTorrent users upload and download files from one another. Such a system is called a PEER-TO-PEER network, often abbreviated as P2P. Each individual computer (including yours) is referred to as a PEER.
The advantage of BitTorrent is that it does not require anyone to maintain an expensive server farm to store massive amounts of data. Thus, BitTorrent access is free and — because you don't have to sign up for anything — relatively anonymous. There is, however, an important disadvantage: because there is no central server, BitTorrent is a less reliable and a lot slower than Usenet.
As an example, I made several tests using both BitTorrent and Usenet. First, I downloaded a very large software file (the latest version of Ubuntu Linux). Next, I downloaded a very large video (a movie). Finally, downloaded a collection of music (an album). You can see the results in the table below.
The first column shows the type of file that was downloaded. The second column shows the size of the file. The next two columns show how long it took to download the file using Usenet and BitTorrent respectively. The final column shows how much faster Usenet was than BitTorrent. For example, when downloading a 667 megabyte movie, Usenet was 14.1 times faster that BitTorrent.
Downloading speeds vary a lot depending on conditions, so I don't want to spend much time analyzing the numbers. The main point I want you to realize is that downloading with Usenet is significantly faster than with BitTorrent. (We'll discuss why in a moment.)
During the first test, it happened that the BitTorrent conditions were as good as they ever get (I'll leave out the details). Nevertheless, Usenet was still more than twice as fast. During the other two tests, Usenet was 14.1 and 31.8 times faster than BitTorrent. In my experience, these two results are far more typical and represent the type of performance you will probably see.
Interesting digression: What would happen if you used BitTorrent to download something huge? As an experiment, I used BitTorrent to download a very large library of video files, 21.1 gigabytes in all. The total download time was 3.2 days (77 hours).
My overall point is not so much that BitTorrent is slow. In fact, BitTorrent is an amazing file sharing system (as long as you are patient). What I want you appreciate is that — compared to other file sharing systems — Usenet is very fast. To see why this is so, we can ask the question: Why is there such a difference between downloading with Usenet and downloading with a network like BitTorrent?
When it comes to file sharing, Usenet has five important strengths. They are:
• Dedicated servers
Let's take a few moments to discuss the details of each of these strengths, one at a time.
TOTAL: 33 peers
Of these 33 peers, 14 were downloading to me,
6 were uploading from me, and 13 were both
downloading and uploading at the same time (as
was my computer).
Availability of the Entire File
To summarize: here are the reasons why Usenet file sharing works so well:
• Very fast
So does that mean you should only use Usenet and not BitTorrent? Actually, I think you should know how to use both.
— hint —
Usenet has a lot of advantages over BitTorrent, particularly speed. However, you will often find that a file for which you are looking is not available on Usenet, but can be found using BitTorrent.
For this reason, if you are serious about file sharing, I recommend that you learn how to use both Usenet and BitTorrent.
(Remember, BitTorrent is free.)
At this point, we have covered the basic ideas regarding Usenet, and we are now ready to get into the details of file sharing. In the following sections, I will explain how Usenet file sharing works and what you have to do to upload and download files. Before we get started, however, I'd like to take a few moments to discuss an awkward, but important question.
© All contents Copyright 2013, Harley Hahn