UUCPNET

UUCP is an abbreviation of Unix-to-Unix Copy. The term generally refers to a suite of computer programs and allowing remote execution of commands and transfer of files, email and netnews between computers.

A command named uucp is one of the programs in the suite; it provides a user interface for requesting file copy operations. The UUCP suite also includes uux (user interface for remote command execution), uucico (the communication program that performs the file transfers), uustat (reports statistics on recent activity), uuxqt (execute commands sent from remote machines), and uuname (reports the UUCP name of the local system). Some versions of the suite include uuencode/uudecode (convert 8-bit binary files to 7-bit text format and vice versa).

Although UUCP was originally developed on Unix in the 1970s and 1980s, and is most closely associated with Unix-like systems, UUCP implementations exist for several non-Unix-like operating systems, including Microsoft's MS-DOS, IBM's OS/2, Digital's OpenVMS (for VAX hardware only), Commodore's AmigaOS, classic Mac OS, and even CP/M.

UUCP can use several different types of physical connections and link layer protocols, but was most commonly used over dial-up connections. Before the widespread availability of Internet access, computers were only connected by smaller private networks within a company or organization. They were also often equipped with modems so they could be used remotely from character-mode terminals via dial-up telephone lines. UUCP used the computers' modems to dial out to other computers, establishing temporary, point-to-point links between them. Each system in a UUCP network has a list of neighbor systems, with phone numbers, login names and passwords, etc. When work (file transfer or command execution requests) is queued for a neighbor system, the uucico program typically calls that system to process the work. The uucico program can also poll its neighbors periodically to check for work queued on their side; this permits neighbors without dial-out capability to participate.

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