X.25 — A standard network communications protocol for implementing the internetwork communications function specified by the third network layer of the ISO/OSI model. It was a recommendation published by the CCITT international communications standards organization as the standard connection between a terminal and a packet-switching network. X.25 is a packet-switched protocol often used in wide-area network configurations across public data communications networks. MS LAN Manager is supported by X.25 communications packages provided by various third-party vendors. See also packet.
X.25 smart card — A hardware card with a PAD (packet assemblers/disassemblers) embedded in it. See also PAD; X.25.
XMM — See extended memory manager.
XModem/CRC — Protocol for transmitting binary files that uses a cyclic redundancy check (CRC) to detect any transmission errors. Both computers must be set to transmit and receive eight data bits per character.
XMS — See Extended Memory Specification.
XMSNETx — Used to load the NetWare Extended Memory Shell at the workstation. The " x " represents the DOS version.
XOR — Acronym for exclusive OR. A Boolean operation in which the Windows NT Server stripe-sets-with-parity form of fault tolerance maintains an XOR of the total data to provide data redundancy. This enables the reconstruction of missing data (on a failed disk or sector) from the remaining disks in the stripe set with parity. See also stripe set with parity; fault tolerance.