| Word | Description |
| X Window System (X Windows) | A consortium-developed, open-standard, device-independent GUI system that is most commonly found on UNIX and Linux operating systems and invoked with the “startx” command. The X Window System was initially developed in 1984 at MIT and called Project Athena. In 1986 the X Consortium was formed to further the development of the GUI. The torch was passed to the Open Group in 1997, and now resides at x.org on the Web. The GUI system works by running an X Server on the client machine that manages the windows, or X Clients. The X Window System uses the client/server architecture in and of itself. |
| X-Windows (X Window System) | A consortium-developed, open-standard, device-independent GUI system that is most commonly found on UNIX and Linux operating systems and invoked with the “startx” command. The X Window System was initially developed in 1984 at MIT and called Project Athena. In 1986 the X Consortium was formed to further the development of the GUI. The torch was passed to the Open Group in 1997, and now resides at x.org on the Web. The GUI system works by running an X Server on the client machine that manages the windows, or X Clients. The X Window System uses the client/server architecture in and of itself. |
| X2 | This is US Robotics’ 56Kbps modem standard that pre-dated V.90. It used the fact that most ISPs were digitally terminated, and this eliminated one analog loop. Due to this fact digital transmissions can remain more intact than previously thought, theoretically allowing for up to 56Kbps data rates, beyond the 33.6Kbps rate that was the earlier ceiling on analog modem transmission speed. See also 56Kflex. |
| X86 | x86 is the generic name for Intel processors released after the original 8086 processor. These include the 286, 386, 486, and 586 processors. As you can see, the "x" in x86 stands for a range of possible numbers. Technically, x86 is short for 80x86 since the full names of the processors are actually 80286, 80386, 80486, and 80586. The "80" is typically truncated to avoid redundancy. If a computer's technical specifications state that is based on the x86 architecture, that means it uses an Intel processor (not AMD or PowerPC). Since Intel's x86 processors are backwards compatible, newer x86 processors can run all the programs that older processors could run. However, older processors may not be able to run software that has been optimized for newer x86 processors. While numbers provide a simple way to distinguish between processor types, they cannot be trademarked. For this reason, Intel's 586 processor is formally known as the Pentium processor. However, software developers still often refer to processors by their number. Of course, what else would you expect from computer nerds? |
| XDS | Exchange Directory Service. |
| XGA | Extended Graphics Array. A video graphics card standard (originally developed by IBM) that supports screen resolutions up to 1024x768x16, i.e. 1024 pixels wide by 768 pixels tall by 16 bit colour (65,536 colours). cf video mode. |
| XHTML | eXtensible HyperText Markup Language (or eXtensible HTML). XHTML is a form of HTML that meets the XML 1.0 specification. It is commonly regarded as the natural successor to HTML. It is defined by a draft specification from W3C. XHTML files often (but not always) have the file extension .xhtml. |
| XML | Extensible Mark-up Language. A specification developed by the W3C and is a mark-up language for structured documents. XML had its roots in specifying and formatting for web documents and web pages, providing a natural development beyond HTML, but it is now also frequently used to provide a common means of data exchange. It supports communication between various companies and applications and is a simplified version of SGML. Despite the various operating system platforms and end devices, data access logic and application logic do not have to be changed. An XML file is a file that is readable using a standard text editor. The file uses tags to indicate the start and end of blocks, with each opening tag having a matching closing tag (although there are exceptions). Since each tag can contain other tags, XML files provide a means of providing a hierarchy of data. Since each tag has a corresponding closing tag it is possible to read an XML file without understanding what each of the tags means, which is why it is possible to build generic XML parsers. See also DTD, JSON and the file extensions .xml and .xsd. Whilst XML files typically have a .xml file extension, they do not have to and many other file extensions are used for specific applications. |
| Xmodem | A protocol for transferring files during direct dial-up communications. Developed by Ward Christensen in 1977, Xmodem has basic error checking to ensure that information isn’t lost or corrupted during transfer. It sends data in 128-byte blocks. Xmodem has undergone a couple of enhancements: Xmodem CRC uses a more reliable error-correction scheme, and Xmodem-1K transfers data faster by sending it in 1,024-byte blocks. See also Ymodem and Zmodem. |
| XOFF | Transmitter off. Used as part of flow control, it is a character (0Fhex, 15dec, ©O) transmitted to suspend output from the sender. cf XON. |
| XON | Transmitter on. Used as part of flow control, it is a character (0Ehex, 14dec, ©N) transmitted to resume output from a sender. cf XOFF. |
| XP | 1. Windows XP. Refers to the Windows XP operating system from Microsoft. Relevant links: www.microsoft.com/windowsxp/default.mspx - Windows XP Home Page 2. XML Protocol. |
| Xsan | Xsan is Apple Inc.'s SAN or clustered file system for Mac OS X. Xsan enables multiple Mac desktop and Xserve systems to access shared block storage over a Fibre Channel network. With the Xsan file system installed, these computers can read and write to the same storage volume at the same time. Xsan is a complete SAN solution which includes the metadata controller software, the file system client software, and integrated setup, management and monitoring tools. Xsan has all the normal features to be expected in an enterprise shared disk file system, which includes support for large files and file systems, multiple mounted file systems, meta data controller failover for fault tolerance, support for multiple operating systems etc. Interoperability Xsan is based on the StorNext File System. [1] The Xsan website claims complete interoperability [2] with the Quantum Corporation StorNext File System: And because Xsan is completely interoperable with Quantum’s StorNext File System, you can even provide clients on Windows, Linux, and other UNIX platforms with direct Fibre Channel block-level access to the data in your Xsan-managed storage pool. [3] Quantum Corporation claims Complete interoperability with Apple’s Xsan and Promise RAID and Allows Xsan and Xserve RAID to support AIX, HP-UX, IRIX, Red Hat Linux, SuSE Linux, Mac OS X, Solaris, and Windows clients, including support for 64 Bit Windows and Windows Vista. [4] This means that the StorNext File System and the Xsan file system must share the same file system layout and the same protocol when talking to the meta data server. They also seem to share a common code base or very close development based on the new features developed for both file systems. All the command line tools for Xsan are beginning with the letters cv which stands for CentraVision - the original name for the file system. |
