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FTP Archives

FTP (File Transfer Protocol) is the way that files are moved from one location to another on the Internet. Using a program called an FTP client ("ftp" under UNIX), you can attempt to log on to any other computer on the network that is an FTP server and in this way gain access to its files.

FTP was originally designed to give people private access to their files on remote machines, and also to furnish them with an easy way to transfer files between their local and remote machines. People soon realized that FTP was also a very good method for giving others access to public files without requiring private system accounts. The files, called an FTP archive, can be accessed by anyone who logs into a general public account named "anonymous" with the password "ftp". Thus, the concept of anonymous FTP was born.

Today the Internet contains thousands of anonymous FTP sites, each open to share information and data files with the Internet community. The rules have changed only slightly from early times. Now most sites require you to give your email address as a password rather than "ftp".

Once you have started to explore the Net using FTP, you will quickly find that many of the more popular FTP archive sites can be quite difficult to log in to during what is referred to as "the peak hours." It may be difficult to imagine 300 people all using a single FTP server at the same time, but consider the tens of thousands of people who access the Internet at any time of the day or night, and realize that most of these people have FTP capability. Actually, once you do successfully log in, you will feel the crawl of an overloaded FTP server at peak hours and experience a 10-minute file transfer (one that would take only 10 seconds if you had only done it at 3 a.m. rather than at 3 p.m.).

FTP Etiquette

FTP etiquette is more or less about not being a file hog and behaving yourself on other people's systems. Here is some common sense advice:

  • Limit the amount of time you spend logged into an FTP site. Other people with needs greater than your own may be trying to access the site.

  • Don't download more than a few files. Each minute you spend online browsing and downloading files is being paid for by the owners of the FTP site on their telephone bill. Yes, the site is offered as a free service, but you shouldn't abuse it. (We compare it to sitting in a restaurant for hours writing a book on a notebook computer while guzzling gallons of free iced tea refills.)

  • Don't upload files to the /incoming directory that the administrators of the FTP site do not want. This includes commercial software and graphics files containing erotic images.

  • When in doubt, read the README (or equivalent) file found in the FTP home directory, or displayed when you log in.

FTP servers are an excellent method of distributing graphics files and related information. Listings of FTP archive sites may be found in FAQ lists posted to the *.answers newsgroups on USENET. You can also ask on relevant newsgroups about any additional FTP sites that may not be listed in a particular FAQ. For example, if you are interested in FTP sites that contain archives of graphics file format specifications, look in the Graphics File Formats FAQ ; you'll find an up-to-date list of sites. For a copy of this list, as well as other FTP sites of interest to graphics programmers and others interested in graphics files, see "Internet Graphics Resources" later in this appendix.

Using an FTP client, you can log into any one of these FTP servers and browse and download their files.

Probably the only bad thing about FTP is that you don't get any fancy menus or searching capabilities. You navigate through the directory tree as you would in MS-DOS, VMS, or a UNIX shell account, reading through the occasional outdated 00index.txt, ls-lR, or README file. Although there isn't a better way to search for files on a specific FTP server, there is a better way to search for files on all FTP servers, as we describe in the next section.

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This page is taken from the Encyclopedia of Graphics File Formats and is licensed by O'Reilly under the Creative Common/Attribution license.