An ISO and ITU standard for addressing and transporting e-mail messages. It conforms to layer 7 of the OSI model and supports several types of transport mechanisms, including Ethernet, X.25, TCP/IP, and dial-up lines.
An ISO and ITU standard that defines how global directories should be structured. X.500 directories are hierarchical with different levels for each category of information, such as country, state, and city. X.500 supports X.400 systems.
(n.) A widely used standard for defining digital certificates. X.509 (Version 1) was first issued in 1988 as a part of the ITU X.500 Directory Services standard. When X.509 was revised in 1993, two more fields were added resulting in the Version 2 format. These two additional fields support directory access control. X.509 Version 3 […]
A windowing and graphics system developed at the Massachusetts Institute of Technology (MIT). MIT has placed the X-Window source code in the public domain, making it a particularly attractive system for UNIX vendors. Almost all UNIX graphical interfaces, including Motif and OpenLook, are based on X-Window.
Xanga (ZANG-uh) is an Internet Web host that provides its users (community) with access to their own online diaries and journals (often called blogs). A person who belongs to the Xanga community is called a “Xangan”. If someone has a Web blog on Xanga, they are being referred to as “having a Xanga.” Xanga services […]
A deductive rule-based query language currently under development by the I4 working group. Xcerpt is for querying XML, RDF and similar data formats. Xcerpt is well-suited for Semantic Web applications and is designed largely for software developers and researchers.