URL (Uniform Resource Locator), method of naming documents or places on the Internet, used most frequently on the World Wide Web (WWW). A URL is a string of characters that identifies the type of document, the computer the document is on, the directories and subdirectories the document is in, and the name of the document.
HyperText Transfer Protocol (HTTP), http means the document is on the WWW. If, instead of http, that part of the URL was ftp, it would mean that that document could be accessed through File Transfer Protocol (FTP), a format that allows a user to list files on, retrieve files from, and add files to another computer on the Internet. Some other schemes are gopher, which indicates the document is on a Gopher system, a menu-driven document delivery system for retrieving information from the Internet; news, which means the document occurs on a Usenet newsgroup, a forum in which users can post and respond to messages; and telnet, which indicates Telnet, an access method in which the user logs on to a remote computer.
The next part of the URL, www2.whitehouse.gov, is called the hostname and represents the computer on which the document can be found: www2 is the name of a specific computer at the whitehouse.gov host computer. The .gov extension identifies the computer as belonging to the United States government. Some other common extensions are .com (commercial) and .edu (education —usually a college or university).
After the computer and host names come the path, or chain of directories, on which the document is found; in this case, the only directory is WH. The last item to be listed is the document name— in this case, Welcome.html.
URLs are case-sensitive, which means that uppercase and lowercase letters are considered different letters, so a user has to enter a URL with all letters in the correct case. URLs on the WWW are accessed with browsers, or computer programs that can connect to the Internet and display Web pages.
The Internet to carry data from one computer to another, each service follows a separate set of rules that define the messages used in the exchange. The Web uses the HyperText Transfer Protocol (HTTP), electronic mail uses the Simple Mail Transfer Protocol (SMTP), and file transfer uses the File Transfer Protocol (FTP). The application programs that users run to access the Internet often blur the distinction among these services. For example, an application program that can send e-mail also allows a user to transfer the contents of a file, and an application program used to access the Web also allows the user to process e-mail.
HyperText Transfer Protocol (HTTP), http means the document is on the WWW. If, instead of http, that part of the URL was ftp, it would mean that that document could be accessed through File Transfer Protocol (FTP), a format that allows a user to list files on, retrieve files from, and add files to another computer on the Internet. Some other schemes are gopher, which indicates the document is on a Gopher system, a menu-driven document delivery system for retrieving information from the Internet; news, which means the document occurs on a Usenet newsgroup, a forum in which users can post and respond to messages; and telnet, which indicates Telnet, an access method in which the user logs on to a remote computer.
The next part of the URL, www2.whitehouse.gov, is called the hostname and represents the computer on which the document can be found: www2 is the name of a specific computer at the whitehouse.gov host computer. The .gov extension identifies the computer as belonging to the United States government. Some other common extensions are .com (commercial) and .edu (education —usually a college or university).
After the computer and host names come the path, or chain of directories, on which the document is found; in this case, the only directory is WH. The last item to be listed is the document name— in this case, Welcome.html.
URLs are case-sensitive, which means that uppercase and lowercase letters are considered different letters, so a user has to enter a URL with all letters in the correct case. URLs on the WWW are accessed with browsers, or computer programs that can connect to the Internet and display Web pages.
The Internet to carry data from one computer to another, each service follows a separate set of rules that define the messages used in the exchange. The Web uses the HyperText Transfer Protocol (HTTP), electronic mail uses the Simple Mail Transfer Protocol (SMTP), and file transfer uses the File Transfer Protocol (FTP). The application programs that users run to access the Internet often blur the distinction among these services. For example, an application program that can send e-mail also allows a user to transfer the contents of a file, and an application program used to access the Web also allows the user to process e-mail.
