gloss_X

X

X Window System (X).

X Window System, developed by MIT, is a graphical user system most often implemented on Unix systems.

X.25.

X.25 is the CCITT and OSI standard for packet-switching networks that provide channels up to 64Kbits/sec. Public and private X.25 networks can be built. In the United States, common X.25 networks are British Telecom, AT&T, CompuServe, and Infonet.

X.400.

X.400 is the OSI and CCITT standard for store-and-forward electronic messaging. It is used for large enterprise networks or for interconnecting heterogeneous e-mail systems. X.400 divides an electronic mail system into a client, called a User Agent, and a server, called a Message Transfer Agent. Message Stores provide a place to store messages, submit them, and retrieve them. Access Units provide communication with other device types, such as telex and fax. Distribution Lists are routing lists.

X.500.

X.500 is the OSI and CCITT specification for directory services. For computer users, a directory service provides a function similar to the function the telephone company's white pages provides telephone users. Using a directory service, computer users can easily look up the location of resources and other users.

Xerox Network System (XNS).

XNS is Xerox's data-communication protocol; it is the basis for the IPX/SPX network protocols used in NetWare.