Introduction to

File Transfer Protocol (FTP)

Prerequisites:

File transfer software, such as:

  • Fetch for Macintosh. This link will enable you to download a copy directly to a disk or onto your hard drive without knowing how to FTP. If that link is too busy, you can also get Fetch from http://www.shareware.com/. (Type in Fetch, select Macintosh as the platform, and click on the Search button. This is a good place to find shareware software in general.)

    Fetch is free for educational use. Make sure you read the section on FTP using a WWW browser and follow the directions before downloading.

  • WS_FTP for Windows (~700K). This link will enable you to download a copy directly to a disk or onto your hard drive without knowing how to FTP.

    Click on the link to download it. This is a light version that is free for educational use. It is a self-extracting archive, so decompression software is not needed.

 

Purpose:

To download and upload files
To use the Internet to find software (new software and upgrades to existing software)

Lesson:

What is FTP?

FTP stands for File Transfer Protocol. It is an Internet service that allows users to download software and other files from machines which hold collections of these software packages and files.

FTP is a client/server application. An FTP client program runs on your computer; and an FTP server program runs on the host computer. The FTP server listens for requests and then sends the requested files to the client. When you log on to an FTP site or server by giving your account number and password, a command link is established across the Internet. The client sends commands such as list files or change directory to the FTP server, which sends status messages back. Once you are connected and ready to download a file, FTP opens a second data connection. Once the file is transferred, the data connection is closed.

Anonymous FTP refers to an FTP site that will let anyone transfer files without requiring them to have an individually assigned user name and password. (Actually, users usually have to give the user name anonymous and enter their e-mail address as the password. This part is done for users automatically when they use a WWW browser to do FTP.) Sometimes you may use a password such as "guest" to download files.

Some Web sites do not require either an individually assigned user name or a password to download software. There are several sites on the Internet that enable you to download freeware and shareware. One great site is: http://www.shareware.com/ You can do a search of the software library by selecting the platform of your choice and keying the title. If you do not know the title of the software, you can also search the archives by topics.

Why would I want to use FTP?

You would want to use FTP to download software packages that are available on the Internet. You would also want to use it to download files of other kinds (data, text, graphics, . . .) that are available on FTP servers around the world. You will also use this concept and file transfer software to upload software for this class.

How do I use FTP?

THE CHOICES:

 


 WWW Browsers (like Netscape or Microsoft Explorer)


Helper Application
Temporary Folder
Some Common File Extensions
 FTP Software - Fetch
 FTP Software - WS_FTP
 Hints for Downloading Software


FTP Using a WWW Browser

You may have already used FTP without realizing it because WWW links can point to FTP sites. In this case, when you click on a link, it automatically contacts the FTP site for the requested information. An FTP address is similar to any other kind of URL, except that it starts with "ftp://"instead of "http://".

When you click on an FTP LINK in WWW, your browser will look at the file extension of the file you are downloading. If the extension is something the browser can show you itself (such as .html, .txt., .jpg, .gif, a menu, a folder or directory), then the browser shows it.

In many cases, the file extension is something (.hqx, .bin, .zip,.sea,xsit, .mpg) that requires a HELPER APPLICATION. If it is properly configured to do so, the browser (Netscape or Explorer) puts the downloaded file in the TEMPORARY FOLDER and launches the specified HELPER APPLICATION using the downloaded file as input. Most Web browsers are pre-configured to run the correct Helper Application for the most common file types/extensions.

In some cases, your web browser or HELPER APPLICATION will ask you where the downloaded or output file should be saved. Make sure you make note of what directory/folder and file name you tell it to use, so you do not have to go searching for it once you have downloaded it to your computer.

SOME COMMON FILE EXTENSIONS

 

HELPER APPLICATION

Files at FTP sites are usually compressed so that they can be downloaded more quickly. Files at FTP sites are frequently archives (a package of) many files so that you can get the package with one transfer, which is much easier than having to transfer each file and folder in the package separately. For example, the file is often a compressed file. File compression simply squeezes a file down into the smallest SIZE="+1>" possible. In this case, your browser will need to launch a HELPER APPLICATION to uncompress and/or unpack this file so that you can use it. Your browser must be configured as to which HELPER APPLICATION it should launch based on the TYPE of file you try to FTP. This is done through your browser's preferences in the APPLICATIONS or HELPER APPLICATIONS area. For MACS, StuffIt Expander is a common helper application to use for .sit, .hqx, .bin, .cpt, and .sea files. File extensions often identify the file type, the computer or software type, as well as the decompression/compression METHOD required.

If you need help checking or setting the Helper Applications on your browser, refer to the page indicated.

You will notice that when you use FTP, frequently more than one file appears. This is because the original file was compressed and/or packaged up as an archive and/or converted to a non-binary format. Your browser brings over the original file (say netscape.sit.hqx). Then your helper application (like StuffIt Expander) converts it back to a binary format (netscape.sit), and then uncompresses it which produces a Netscape folder. When you are done, you are left with all three of these files, though you need to keep only the Netscape folder.

If you are using a MAC, you will need the Helper Application called StuffIt Expander. In most cases, your computer will already have StuffIt Expander. Frequently your Internet service provider will give you this software in the initial set of software they give you to connect to the Internet. If you do not have it, see if you can get it on a floppy disk from your school or a friend. StuffIt Expander is free and very common. We ask you to get it on a floppy disk because there is a Catch 22 involved in downloading StuffIt Expander from the Internet if you don't have it already. Basically, you need Fetch to download StuffIt Expander and you need StuffIt Expander to download Fetch. So you need to get either Fetch or StuffIt Expander initially from a floppy disk. Contact your facilitator if you have this problem.

 

Temporary or Download Folder

In other cases, your Web browser automatically saves the output file in the same folder as the input file, which is probably the TEMPORARY FOLDER. Where can you find this TEMPORARY FOLDER that now contains your downloaded file? The TEMPORARY FOLDER or DOWNLOAD FOLDER is usually something you can configure in your Web browser preferences. You can check the current setting in your Web browser preferences to see where your downloaded files will go. See below for information about specific browser and platforms.

Internet Explorer Users: From your Explorer Edit menu, select Preferences which is at the bottom of this menu. On the left-hand side of the box, click on the Receiving Files category to expand the list. Then click on the Download Options item in the list. On the top of the right-hand side, look at the folder/directory specified for the Download Folder field. This is where your downloaded files will go. If you wish to change this setting, use the Change Folder button and select a folder/directory using the dialog box that pops up.

Netscape 2 and MAC Netscape 3 Users: From your Netscape Options menu, select General Preferences. Then select the Applications tab. At the bottom of this dialog box, look at the folder/directory specified for the Temporary Directory. This is where your downloaded files will go. If you wish to change this setting, use the Browse button and select a folder/directory using the dialog box that pops up.

MAC Netscape 4 Users: From your Netscape Edit menu, select Preferences which is at the bottom of this menu. On the left-hand side of the box, click on the Navigator category to expand the list. Then click on the Applications item in the list. On the bottom of the right-hand side, look at the folder/directory specified for the Download Files To field. This is where your downloaded files will go. If you wish to change this setting, use the Choose button and select a folder/directory using the dialog box that pops up.

PC Netscape 3 and 4 Users: (from http://help.netscape.com/) "There isn't a preference setting within the user interface where you can specifiy the default download directory; rather, Communicator remembers the directory you last downloaded a file into and will default to that location the next time you attempt to download a file to your hard dirve. If you wish to change the download directory, the next time you save a file to your hard drive, enter the directory of your choice into the Save As window."

It is important to remember that caution should be exercised when downloading files. It is preferable to download only well-known applications from well-known sites. Virus protection software like Disinfectant should also be on hand. Software such as Norton Utilities can help you recover if you do download something that turns out to be harmful.

Hints for Downloading Software

  1. Get virus protection software on your machine. (Examples: Disinfectant for Mac, Norton for MS-DOS)
  2. You must have StuffIt Expander (Mac) or PKZip (MS-DOS) in order to uncompress the software.
  3. Your Netscape Helper Applications must be set to use StuffIt (for files ending in .sea, .sit, .hqx) or PKzip (for files ending in .zip).
  4. You can use a search engine to find software. Netscape and NCSA and other places have nice lists on where to get the various Helper Applications.
  5. The software goes to wherever your Netscape "Temporary Folder" is set. You should make sure this folder/directory exists on your machine before going any further.
  6. Check that your e-mail and address are set in your Netscape Preferences. Many anonymous FTP sites require your e-mail address to be used as your password. So Netscape gives the FTP site the e-mail address you filled in for your Netscape preferences. If you do not fill in your e-mail address, the FTP site may deny you access.
  7. You can use Netscape to download software. Just click on the link provided that shows a file ending that your computer understands (.sea, .sit, .hqx for Mac, .zip for PC). This is usually an FTP - "ftp://...".
  8. The compressed, stuffed, and normal versions will show up in your Netscape "Temporary Folder." You need to keep only the normal (i.e., unstuffed and uncompressed) version. Move this folder or file to where you want to install the software.
  9. If you are downloading a copy of a software program, look for an "Installer" file or a file with the extension ".exe" in order to install and/or run the program.
  10. If you downloaded an "Installer" program, use the installer.
  11. Read any files named README, INSTALLATION NOTES, KNOWN PROBLEMS, LICENSE, etc. to see if there is anything else to do or look out for (and to see if you need to pay a fee for the software).
  12. You may need to set some preferences for the software once you have installed it.
  13. Start using the software. Add an alias in the Apple Menu if you like or make a shortcut on your MS-DOS machine desktop.

 

Task 1: Downloading a Templates Folder

Before you start writing your project Web pages, you will need to FTP a templates folder. The account, host computer, and directory information given on this page is for demonstration purposes only. You will need to use the host computer name, user ID, password, and directory given by your facilitator.

If you were taking this class at Fermilab, you would open the FTP software and use the following information. The templates folder is found at host: www-ed.fnal.gov. You will need to enter your name and password. Then open edwebserver. Next open lincon. Scroll down until you reach the folder named: templates. (This is not the same as template.shtml!) Make sure you get the entire folder. The folder contains a graphics folder, and templates for the presentation, scenario, student, rubric, staff development and etc. Web pages. Please follow the format on these Web pages. Using the template should also save you some typing. After you have saved this folder, close your connection. You may now work on your project Web pages following your facilitator's directions. Upload your pages to your course server as directed.

For detailed instructions on downloading the whole templates folder, please see:

Task 2: Determining the URL for Your Own Web Pages

Once you have progressed with your project to the point that you have uploaded your project folder to the Web server, you will need to know the URL of your new Web pages so that you can preview them and check them for link and image problems. But what is the URL for your new Web pages?

Can you figure out what it should be? A few hints: The purpose of a URL for a Web page is simply to give "directions" on how to find that Web page on the Internet. Think about the directions you would need to give someone to find the Web pages you just uploaded. What information would they need to know?

Note that the computer that you FTP files to is the same computer that serves your files on the Web (i.e., same computer name, folder names and file names). So the same "directions" you needed to FTP your pages are needed in the URL for your pages. Another important thing to note is that the Web server runs on that computer and assumes all folders and pages start from a default top level folder. (At Fermilab, the name of this default top level folder is "edwebserver".) Because the Web server automatically looks for folders and files starting in that default top level folder, you should not include that top level folder name in your URL. Example: At Fermilab, "edwebserver" would not appear in your URL.

Now, try to guess the URL for one of your recently uploaded project Web pages. Open this URL in your browser to see if you were right! This information (the URL of your project pages) will be needed by your facilitator in order to view and to provide comments and suggestions.

If you need more hints, review the information about determining the URL for your uploaded files.

Whenever you FTP files, consider how long the URL will be and how easy it will be to remember for others. By keeping your file names and titles short and easy to use more people will be likely to view your project pages.

Knowing how URLs work can also help you find what you want when you are given an incorrect URL by someone else. You can use this information to "back up" in a URL to find other Web pages on the Web server that might lead you to the page you wanted. For example, if you were given the URL http://www.apple.com/folder1/folder2/myfile.html and found it broken, you could then check if any of the following worked to help you find the page you wanted.

  1. http://www.apple.com/folder1/folder2/myfile.htm
  2. http://www.apple.com/folder1/folder2/
  3. http://www.apple.com/folder1/
  4. http://www.apple.com/