File Transfer Protocol, usually referred to as FTP and Hyper Text Transport Protocol (HTTP) are two technologies for engaging in one of the most important activities on the Internet. They're important because they allow you to take files from a remote computer and place them on yours--this is called "downloading." You can also do the opposite, should you be so inclined and the remote computer is agreeable--this is called "uploading." This is one of the foundations on which the Internet was built: the easy transfer of files from place to place.
Some of you may say, "why do I care about exchanging programs? I don't care about software. I'm no chip-head." Well, if you said that, you'd be wrong--it is very important to know about and keep-up with new application software. You wouldn't buy a car and say, "I don't care about gasoline, I'm no motor-head." Software is a driving force for ongoing innovation of electronic media technologies. It is a kind-of fuel for your computer!
You also need to know about file transfer because it is via FTP that most users place web page(s) on web servers.
Today, FTP and HTTP are used to exchange application software (e.g., much of today's new software, such as new web browsers and plug-in components), text documents, images, sounds, and a whole host of other things that can be captured in a computer file. The important thing to remember about these items is that they require a computer which is software or hardware-equipped to handle them.
For instance, you may find files that were designed to work on a Macintosh computer. It makes sense for you to download them only if you have a Mac on which to use them. Similarly, you may find files that are formatted for Photoshop. If you don't have a copy of Photoshop on your computer, or another app that can translate Photoshop files, you won't be able to view the file. The same can be said for many other files, particularly multimedia.
I won't be able to teach you everything about file transfer in this lesson, but my goal is to get you started and give you an overview. For further information, I would recommend several of the Internet guides I mentioned in Lesson 1, including many resources in the library and on the Internet.
Introduction to File Transfer on the Internet
Worldwide there are thousands of computer servers chocked full of software and information for you to download (copy to your computer). In this example, we'll focus on software archives. These archives are so popular that any one particular site might be inundated by eager users, and hence unavailable to any other users. The answer? Many back-up copies of these archives have been established to spread-out the workload among many computer archives. These back-ups are called "mirrors," as in mirror copies. These mirrors are spread-out strategically across the globe to make it easy to find and download the items you need.
Browsing and Searching Software Archives
Fortunately for us, much of the difficult work of file transfer (finding archives, searching for files, transferring files, etc.) has been automated and streamlined via the WWW. Several large web sites specialize in making file transfer easy and efficient. One of the most popular sites for finding free software on the WWW is a site called C|Net Downloads, also called Download.com located at:
http://download.cnet.com/
At Download.com, you can browse for software in the same way you can browse for books in the library or you can search for software titles which satisfy a particular request. Browsing works well if you know for what you're looking, or perhaps want to be surprised by what you find. Later I'll mention some sites you can browse. Searching is usually the preferred method, and it is file searching on which we'll focus.
First, point your web browser to Download.com. Once you're at Download.com, you should focus your search on the particular type computer system you use (Macintosh, Windows, Mobile, etc.). This can be indicated by using the ballot boxes near the [Search] bar on the right (see image below). For this example, make sure to specify the proper type of platform BEFORE you perform your search.
Next, type in your search term in the space provided. For this example, type "gradebook" and then click the [Go] button. Download.com will find files which satisfy your request and return to you a list of these files. It will also display a brief description of the files it found.
Scroll through this list to find the names and descriptions of programs and other files available via Download.com. A hyperlink at the top and bottom of the page (labeled "2," "3" or (>) allows you to see additional selections.
The blue file names in the center of the page are hyperlinks. Below the links are abstracts--very short descriptions of the files. Read the abstracts to see which file you'll want to download. Select it by clicking once on its title (i.e., The Blue Title) to get more information or if you're ready to download, click the "Download Now" button on the right. Look at the image below to see how it may appear.
Navigating Your Hard
Drive
Your web browsing software will place the file on the hard drive of the computer you're using--but where? The answer to that question is determined by your web browser, often just before the download commences. Pay attention to the dialog box that may appear just after you click the download button. It is at this point that you'll get a chance to specify to where you want the download saved (most often your Downloads folder which is in your Home folder.
If you don't find the downloaded file in your computer's Downloads folder or Desktop, then perhaps your web browser has placed the file in some other folder, perhaps the Documents folder or some other folder. Rather than manually hunting over "hill and dale" to find the file, simply use the Finder's "Find..." command, which can be selected from under the File menu (on a Mac) or use Windows Explorer (in Windows) to find it. Type in at least some part of the downloaded file's name and let the computer do the finding for you!
You can also go directly to software vendors' web sites and browse for the software you want. This is very efficient if you know the file(s) for which you're looking. A link allowing you to browse the archive of available downloads is usually available on the Downloads page of each vendor's support web site.
Now I wish this was all there was to know about file transfer, but it's not quite that easy. In order to facilitate the economical transfer of files along the Internet, files are often encoded and compressed. Let's discuss this next.
Retrieving Encoded and Compressed Files
Many of the files in online archives are binary files, i.e., application software. They can be downloaded, but they are typically encoded and compressed. They are compressed (more commonly referred to as "stuffed" or "zipped") so they download faster, but...why are they encoded?
Why Are Files Encoded?
If you recall from some of our earlier lessons, the Internet is a network that was originally designed for sending text messages between computers. Text messages need only 7-bits of data, so many internet gateways are 7-bits wide by default. Most non-text files that we use are larger than 7-bits wide. If a 16-bit or 32-bit wide file is sent across the internet, they can lose much of their content and be rendered unusable. It's a bit like sending a big truck through a small tunnel. The most common way to get around this bit-width problem is to encode the too-wide file into a 7-bit wide format (actually a text format). This process will actually make the file longer in file-length, kind of like making a snake out of Silly Putty.
For Mac users, BinHex is the standard 7-bit encoded format because it preserves the Mac file structure. BinHex file names usually have a '.hqx' suffix. UUencoding (UU stands for Unix-to-Unix) is another 7-bit encoding method, but it only encodes part (the data fork) of a Mac file. UUencoding is common for files that are not platform-specific such as graphics files. UUencoded files usually have a '.uu' or '.uue' filename suffix.
So, what do we do about these issues? Again our trusty helper applications (remember helper applications in Lesson 10?) come to the rescue! They should (don't you wish you had a nickel for every should you've ever been promised?) automatically recognize when a downloaded file is encoded by looking at its file extension (Mac= .hqx, PC=.exe) and that it is compressed (Mac= .sit, PC= .zip) and perform the proper operation(s) on the file to make it usable. If your web browser does not automatically perform these operations, you will need to run the proper translation software yourself.
The most popular programs for this
procedure are StuffIt Expander (on the Mac or Windows) and WinZip (on the Mac or Windows).
A
copy of StuffIt Expander for Macintosh should be located on each lab
computer on campus and WinZip or StuffIt Expander for Windows on
every PC. If you are using a machine which does not have the proper
helper application, you may need to get a copy to complete this
activity. You can go
directly to the manufacturer, StuffIt or
WinZip.
Click the button or text link below to go to the program's home page. There will be more instructions available when you get
there.
If you need to do the file translation manually, locate the file you just downloaded (in our example, it probably has a filename such as "gradebook.sit" or "gradekeeper.zip") and open it using the helper app you have installed on your computer.
Some Choice Sites
There are too many file transfer sites to recount them all here, but a few are: Download.com, Jumbo.com, Tucows.com, and VersionTracker.com.
Conclusion
I hope that this lesson has made file transfer a little less daunting for you. There are a lot of good resources to be downloaded. You're bound to see mention of lots of software files as you peruse the 'Net, so it makes sense to know how to get them.
Internet Lessons version 2.0. Copyright of lessons (C) 2011 by Joseph A. Erickson, All Rights Reserved. Permission Granted for Individual Usage.
If you plan to distribute multiple copies of this work, please contact the author.
