"The art of being a good guest is to know when to leave."
--Prince Philip, 1962
FTP (File Transfer Protocol) is another one of many "client/server" applications on the Net. It is both a program and a method used to transfer files between computers connected to the Net.
While telnet program allow you to do remote computer connections for "interactive" sessions (searching a library OPAC, checking your mail on a remote system, querying a remote database), FTP is a very special purpose tool. As its name implies, it is used exclusively for transferring files between remote computer systems on the Internet. And we'll see, using FTP you can transfer files and software to and from public file archives and your own computer.
In order to use the FTP function, you must have an FTP client program installed on your local computer system (i.e., the system which provides you with Internet access). Thousands of hosts on the Internet run FTP server programs, which allow them to "serve" or archive files for public access.
Using the FTP command, you can also transfer files between different computers where you have userid/password access; in our lessons, however, we will concentrate on the public archives. There are literally thousands of public FTP file libraries, or archives, on worldwide Internet-connected systems. These public archives require no userid/password -- you can login using the userid "anonymous" (no quotes, lowercase), and when prompted for a password, you enter your own email address.
You will find many types of files available at anonymous FTP sites: historical documents, electronic books and journals; images of paintings and artwork; photographs; sound files; data files; computer software, and much more. Often, specific sites maintain archives of documents/files of a special nature, for example, Macintosh software or the public information documents for a government agency. You can think of these as "special collections" that you might want to explore and -- maybe -- get.
First, however, you have to find out if your computer system supports FTP file transfers and, if so, the name of the FTP client program you'll use. (If you don't have FTP access, you can obtain these files through email requests, and also through gopher and WWW browsers. I'll show you how at the end of the next lesson.)
Second, you'll need to know the exact name and location of the particular file that you want to retrieve. Location information should include the hostname of the FTP server and the directory path that leads you to the file you're after, e.g.:
Host site byrd.mu.wvnet.edu Directory path: /pub/history
This is a good history source for files on everything from a Civil War bibliography and pictures to Roosevelt's Inaugural Addresses to the Gulf War.
In Lesson 24 I'll show you how to use a tool called ARCHIE to locate the hostname and directory path to specific files available via FTP, so don't worry for now how to come by this information...
Finally, you should keep in mind that transferring really large files across the network places considerable strain on the computing power of a site during heavy-use business hours. Proper netiquette says that, if possible, you should connect to most FTP sites between the hours of 6:00 p.m. and 6:00 a.m. -- their time -- when you intend to transfer especially large files.
Now, assuming you have an FTP client program on your Internet host, here's an approximation of how you would retrieve a file. Ask your local guru how to initiate the FTP connection (you may enter commands like "ftp" and "OPEN hostname" or you may start up a graphic FTP program by launching it and indicating in the box provided the name of the host where you wish to connect.)
Once the initial connection has been negotiated, the remote server will ask you to login, usually like this:
This is where the term, "anonymous ftp" comes from. When you ftp to a site and login as anonymous, you are browsing through files that have been created by that site for public use. Any number of folks can access these files simultaneously. At the same time, the site is still able to maintain the security of other files that are not open to the public (folks with accounts on the remote system can continue to use FTP to login and access their personal files.)
If the anonymous connection is successful, you will usually receive a message similar to:
The system will usually mask the password, and you'll see a display
This login procedure is like signing a guestbook -- the server makes a record of your visit!
At most FTP sites, after completing the login routine, you'll see only a brief welcome message (at some sites, you'll not even get this!) and then, if you're working from a command-based site, you'll be presented with a command prompt; in my system it's:
You may see a command prompt such as:
At this point, nothing else will happen until you type something; the system is awaiting a command from you. If you're lucky enough to be using a graphic FTP program, your interaction with FTP sites will be much easier. It won't hinge on your remembering and entering cryptic commands -- you'll be using pull-down menus and buttons to navigate seemingly treacherous archives (and you can select files and directories with which to interact simply by pointing and clicking your mouse). Those of us at the mercy of a command-based ftp program, unfortunately, aren't so lucky; we'll have to learn the commands.
Here's a basic checklist of FTP commands common to most systems.
There are other commands, but these are all you'll need to get started.
NOTE: when referencing directories and files on the public archive remember that case distinctions are critical. If a directory is named 'pub' and you issue "cd PUB", you'll receive an error message!
Here are some anonymous ftp sites you can visit and look around:
hostname: ftp.csd.uwm.edu directory path: pub filename: inet.services.txt
In some systems, you may need to rename the file before you can transfer it; look for directions on how to do this in Lesson 23.
A FAQ on Anonymous FTP is available via the WWW at:
|"BCK2SKOL" is a free electronic library classroom created by Ellen Chamberlain, Head Librarian, University of South Carolina Beaufort, and Miriam Mitchell, Sr. Systems Analyst, USC Columbia. Additional support is provided by the Division of Libraries & Information Systems, University of South Carolina Columbia.|
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