Guide to Computer Acronyms, Part 2
Find out what all those perplexing capital letters mean.

The following list of acronyms and definitions is the second in a two-part series that began in the previous issue's Tutor column (January 9, 1996). Tear out these pages and combine them with the pages from the last issue and you'll have a handy list of common computer acronyms to help you as you read computing literature. Or you can download an electronic copy of the combined articles from PC Magazine Online. The file is named ACRNMS.ZIP, and you'll find it in ZD Net's Utilities/Tips Forum library  on CompuServe (GO ZNT:TIPS) or in the issue archive file (V15N02 .ZIP) on other services as well as the Internet.
As in Part 1, this guide provides pronunciations for acronyms that are usually pronounced as words rather than spelled out letter by letter.

OCR (optical character recognition) A technology that allows dots or pixels comprising characters in a bitmapped image to be converted into ASCII text. OCR is frequently combined with scanners to scan documents into a computer and convert the resulting information into textual data.

ODBC (Open Database Connectivity) A standard promulgated by Microsoft that allows databases created by various database management programs-such as dBASE, Microsoft Access, Microsoft FoxPro, and Oracle-to be accessed using a common interface independent of the database file format. By relying on ODBC, one can write an application that uses the same code to read records from a dBASE file or a FoxPro file. Internally, ODBC drivers use a form of SQL to carry out database operations. See also SQL and WOSA.

OLE (Object Linking and Embedding) Pronounced "oh-lay." A complex specification that describes the interfaces used for such tasks as embedding objects created by one application within documents created by another, performing drag-and-drop data transfers within or between applications, creating automation servers that expose their inner functionality to other programs, extending the Windows 95 shell with custom DLLs, and much more. Version 1.0 of the specification was originally created for placing objects such as Excel spreadsheets inside documents created by other applications such as Microsoft Word for Windows. OLE 2.0 greatly expanded the scope of OLE and made the original name obsolete, but the name had achieved widespread recognition and was retained.

PCI (Peripheral Component Interface) A 32/64-bit local bus architecture developed by DEC, IBM, Intel, and others that is widely used in Pentium-based PCs. A PCI bus provides a high-bandwidth data channel between system-board components such as the CPU and devices such as hard disks and video adapters. PCI is one of two widely adopted local-bus standards. The other, the VL-Bus, is primarily used in 486 PCs. See also VLB.

PCL (Printer Control Language) The printer language that drives HP DeskJet, LaserJet, and other Hewlett-Packard printers. PCL defines a standard set of commands enabling applications to communicate with HP or HP-compatible printers. For example, the command <Esc>&l16D, where <Esc> represents an escape character (the ASCII value 27), configures a PCL printer to print 16 lines per inch. PCL has become a de facto standard for laser and ink jet printers and is supported by virtually all printer manufacturers. HP compatible or LaserJet compatible means that a printer supports the PCL  command set.

PCMCIA (Personal Computer Memory Card International Association) A consortium of computer manufacturers that devised the standard for the credit card-size adapter cards used in many notebook computers. PCMCIA defines three card types: Type I cards can be up to 3.3 mm thick and are generally used for RAM and ROM expansion cards; Type II cards can be as thick as 5.5 mm and typically house modems and fax modems; Type III cards are the largest of the lot (up to 10.5 mm thick) and are mostly used for miniature hard disks. PCMCIA support is a major component of Windows 95's Plug and Play architecture, which automatically recognizes when PCMCIA devices are added and removed. (The simpler term PC Card has largely replaced this acronym to refer to these cards.)

PDA (personal digital assistant) A hand-held computer, such as the Apple Newton. PDAs typically use pens for input, rather than keyboards, to conserve space.

PIC (programmable interrupt controller) Pronounced "pick." A chip or device that prioritizes interrupt requests generated by keyboards, serial ports, and other devices and passes them on to the CPU in order of highest priority. See also IRQ in Part 1.

PIF (program information file) Pronounced "piff." A binary file in which Windows stores configuration information about a DOS program. A PIF file includes such information as the path to the executable file, the amount of memory the program requires, and whether the window in which the program is run closes automatically when the program terminates.

PIM (personal information manager) Pronounced "pimm." A software application designed to store and manage "personal" information such as schedules, phone lists, and contact notes.

PnP (Plug and Play) The technology that lets Windows 95 automatically detect and configure most of the adapters and peripherals connected to a PC. A fully Plug and Play-enabled PC requires three PnP components: a PnP BIOS, PnP adapters and peripherals, and a PnP operating system. Adding a PnP-compliant CD-ROM drive, hard disk, monitor, printer, or other device to a PnP PC requires little more than making the physical connection. The operating system, in conjunction with PnP logic present in the BIOS and in the device itself, handles the IRQ settings, I/O addresses, and other technical aspects of the installation to ensure that the device doesn't conflict with other installed devices.

PPP (Point-to-Point Protocol) A protocol that allows a computer to connect to the Internet through a dial-in connection and enjoy most of the benefits of a direct connection, including the ability to run graphical front ends such as Mosaic and Netscape Navigator. PPP is generally considered to be superior to SLIP, because it features error detection, data compression, and other elements of modern communications protocols that SLIP lacks. See also SLIP.
QBE (query by example) A database query method in which the user forms a query by filling in a table with examples of the requested information. IBM created QBE in the 1970s to simplify the process of retrieving information from mainframe databases; it was later implemented on the PC platform in such products as dBASE and Paradox. See also SQL.

RAM (random access memory) Pronounced "ram." The generic term for read/write memory-memory that permits bits and bytes to be written to it as well as read from it-used in modern computers. RAM comes in several forms, and manufacturers are continually coming up with new designs to provide the fastest possible access times at the lowest possible cost. See also DRAM, EDO RAM, SRAM, and VRAM.

ROM (read-only memory) Pronounced "romm." The generic term for memory that can be read from but not written to. A computer's BIOS is typically contained in ROM. This offers two advantages: The code and data in the ROM BIOS need not be reloaded each time the computer is started, and they can't be corrupted by wayward applications that write into the wrong part of memory. Some forms of ROM can be rewritten by applying higher-than-normal voltages to the inputs and holding the voltages for several milliseconds. See also BIOS, EPROM, and EEPROM.

RISC (reduced instruction-set computing) Pronounced "risk." A microprocessor architecture that favors the speed at which individual instructions execute over the robustness of the instruction set. The PowerPC architecture is one example of a RISC microprocessor design. (For details, see the Tutor column of October 24, 1995.) See also CISC.

SCSI (small computer system interface) Pronounced "scuzzy." A powerful and flexible peripheral-connect interface popularized on the Apple Macintosh and used to connect hard disks, CD-ROM drives, tape drives, and other mass-storage devices to PCs of all types. SCSI and SCSI-2, an enhanced version of the original SCSI specification (now sometimes referred to as SCSI-1), excel at handling large hard disks and permit up to eight devices to be connected along a single bus provided by a SCSI connection. See also IDE.

SGML (Standard Generalized Markup Language) A text-based language for describing the content and structure of digital documents. HTML, which has gained fame as the language used to create World-Wide Web pages on the Internet, is a descendant of SGML. SGML documents are viewed with transformers, which render SGML data the way Web browsers render HTML data. See also HTML and VRML.

SIMM (single in-line memory module) Pronounced "simm." A form of chip packaging in which leads (pins) are arranged in a single row protruding from the chip. Connectors are attached to a stiff contact strip that permits a SIMM to be inserted into a slot like an expansion adapter. On PCs, SIMM-style RAM chips have virtually replaced the dual in-line package (DIP) chips, identifiable by two rows of protruding legs, that were popular in the 1980s.
SLIP (Serial Line Internet Protocol) Pronounced "slip." A protocol that allows a computer to connect to the Internet through a dial-in connection and enjoy most of the benefits of a direct connection, including the ability to run graphical front ends such as Mosaic and Netscape Navigator. SLIP is also used to run TCP/IP over phone lines. See also PPP and TCP/IP.

SQL (structured query language) Pronounced "sequel." A query language developed by IBM that relies on simple English-language statements to perform database queries. Almost universally supported in one form or another by relational databases on platforms of all types, SQL allows databases from different manufacturers and on different types of computers to be queried using a standard syntax. See also ODBC and QBE.

SRAM (static random access memory) Pronounced "es-ram." A form of RAM that retains its data without the constant refreshing that DRAM requires. SRAM is generally preferable to DRAM because it offers faster memory access times (a critical element in a PC's performance), but it is also more expensive to manufacture because it contains more electrical components. The most common use for SRAM is to cache data traveling between the CPU and a RAM subsystem populated with DRAM; this boosts performance by reducing the number of DRAM accesses required. See also DRAM.

SVGA (Super Video Graphics Array) An extension of the VGA video standard. SVGA enables video adapters to support resolutions of 1,024 by 768 pixels and higher with up to 16.7 million simultaneous colors (known as true color). See also VGA.

TAPI (telephony application programming interface) Pronounced "tappy." A set of functions supported by Windows that permits Windows applications to program telephone-line-based devices such as modems and fax machines in a device-independent manner. One of numerous high-level device interfaces that Windows offers as part of the Windows Open Services Architecture (WOSA), TAPI simplifies the process of writing a telephony application that works with a wide variety of modems and other devices supported by TAPI drivers. See also WOSA.

TCP/IP (Transmission Control Protocol/Internet Protocol) A set of communication protocols developed by the U.S. Department of Defense that allows dissimilar computers to share information over a network. While networking two identical PCs is no longer a huge technological challenge, TCP/IP provides a solution to the stickier problem of connecting a Pentium PC to, say, a DEC minicomputer or a Silicon Graphics workstation. TCP/IP is the glue that binds the Internet.

TIFF (Tagged Image File Format) Pronounced "tiff." A popular file format for bitmapped graphics that stores the information defining graphical images in discrete blocks called tags. Each tag describes a particular attribute of the image, such as its width or height, the compression method used (if any), a textual description of the image, or offsets from the start of the file to "strips" containing pixel data. The TIFF format is generic enough to describe virtually any type of bitmap generated on any computer, but it is also complex and difficult to write software for.

TSR (terminate-and-stay-resident) The common name for DOS programs that terminate but remain resident in memory so they can operate in the background while other programs execute in the foreground. One of the first (and best-known) TSRs was Borland's Sidekick. By hooking keyboard interrupts, it could detect when a certain combination of keys was pressed and respond by popping up a window for the user to work in. TSRs were popular in the 1980s because they provided a means for a single-tasking operating system (DOS) to perform two or more tasks at once.

UART (Universal Asynchronous Receiver/Transmitter) Pronounced "you-art." The chip that drives a serial port. IBM chose the National INS8250, better known simply as "the 8250," for the serial ports in its original PC. Enhanced versions of that chip-or custom logic that mimics the functions of the 8250-are still used in PCs today.

UMB (upper memory block) A block of memory (between 640K and 1MB) created in upper memory by a 386 memory manager. This is useful for loading TSRs and device drivers so they don't occupy the limited memory below 640K. See also TSR and UMA.

URL (Uniform Resource Locator) A logical address that identifies a resource on the Internet. For example, the URL

http://www.zdnet.com/~pcmag/utils/utility.htm

is the Internet address of a Web page that gives you access to PC Magazine's utilities. In this example, http names the protocol (Hypertext Transport Protocol) used to access the page; www stands for World-Wide Web; zdnet is the institution that operates the server computer, in this case Ziff-Davis; .com signifies company (as opposed to .gov for government, .org for nonprofit organization, or .edu for educational institution); /~pcmag/ utils/ is the directory on the host computer; and utility.htm identifies the HTML filename for the page itself.

VESA (Video Electronics Standards Association) Pronounced "vee-suh." The consortium of computer manufacturers responsible for the SVGA video standard and the VL-Bus, a local- bus architecture. See also SVGA and VLB.

VFAT (virtual file allocation table) Pronounced "vee-fat." The 32-bit file system that Windows 95 uses to manage information stored on disks. An extension of the FAT file system, VFAT supports long filenames while retaining compatibility with (and many of the limitations of) FAT volumes. See also FAT.

VGA (Video Graphics Array) Also referred to as Video Graphics Adapter. The standard for the graphics adapter built into most IBM PS/2 systems, VGA quickly replaced earlier standards such as CGA (Color Graphics Adapter) and

EGA (Enhanced Graphics Adapter) and  made the 640-by-480 display showing 16 colors the norm. Other manufacturers have since extended the VGA standard to support more pixels and colors. See also SVGA.

VLB (VESA Local Bus or VL-Bus) The local-bus standard created by the Video Electronics Standards Association (VESA) to provide a fast data connection between CPUs and local- bus devices. The VL-Bus was widely used in 486 PCs, but most Pentium PCs use PCI local buses instead. See also PCI.

VR (virtual reality) The technology that uses computer-generated sights and sounds to transport users to new worlds that exist only inside the computer. A key component of virtual reality is immersion-blocking out the real world so as to make virtual worlds seem more real. A VR headset that combines computer-generated images displayed inches from the eyes with an audio component is a commonly used immersion tool.

VRML (Virtual Reality Modeling Language) An open standard for 3-D imaging on the World-Wide Web that paves the way for virtual reality on the Internet. The way VRML code describes a 3-D scene is analogous to four points describing a square, or a center point and radius describing a sphere. VRML viewers, similar to HTML Web browsers, interpret VRML data downloaded from the Web and render it on your computer. This allows the bulk of the processing to be performed locally and drastically reduces the volume of information that must be transmitted from the Web-a key consideration if rendering is to be performed in real time.

VRAM (video random access memory) Pronounced "vee-ram." A form of DRAM specially suited for video adapters. VRAM differs from common DRAM in that it features a "dual-ported" design allowing two devices to access it at once. Thus the CRT controller, which converts bits and bytes in video memory to pixels on the screen, and the CPU, which manipulates the contents of video memory, can access VRAM simultaneously. In video boards fitted with the less expensive DRAM, performance suffers somewhat because the CRT controller and the CPU must takes turns accessing the video buffer. See also DRAM and WRAM.

WAIS (wide-area information server) A system for searching huge distributed database servers across a network, usually the Internet. WAIS allows you to perform a keyword search; it's analogous to an index, whereas Gopher, which is sometimes used as a complement to WAIS, is analogous to a table of contents.
WAN (wide area network) Pronounced "wan" to rhyme with "LAN." A geographically dispersed network formed by linking several computers or local area networks (LANs) together over long distances, usually using leased long-distance lines. WANs can connect systems across town, in different cities, or in different regions of the world.

WOSA (Windows Open Services Architecture) Pronounced "woe-suh." A collection of APIs that provide standard ways for Windows applications to access databases, telephony devices, messaging services, and other services. ODBC and MAPI are two examples of APIs that fall under the WOSA umbrella. See also ODBC, MAPI, and TAPI.

WRAM (Windows random access memory) Pronounced "double-you-ram." Similar to VRAM, but with added logic designed to accelerate common video functions such as bit-block transfers and pattern fills. WRAM is priced competitively with VRAM and can substantially speed up certain graphical operations such as video playback and screen animation. See also VRAM.

WWW (World-Wide Web) A collection of richly formatted hypertext "pages" located on computers around the world and logically linked together by the Internet. With a graphical Web browser such as Mosaic or Netscape Navigator, users can "surf" the Web by clicking highlighted words on the screen. Each click activates a hypertext link, connecting the user to another Web location identified by a URL. See also HTML and URL.

WYSIWYG (What You See Is What You Get) Pronounced "wizzywig." Screen output that exactly (or very closely) matches the appearance of printed output. WYSIWYG displays were once rare on the PC platform, because most applications ran in character mode and had little control over the format of text rendered on the screen. Today WYSIWYG applications abound, because Windows allows more precise control over screen formatting and provides a device-independent interface to both screens and printers.

XMS (Extended Memory Specification) A memory allocation scheme developed by AST Research, Intel, Lotus, and Microsoft that allows real-mode programs to use extended memory (memory above 1MB) without interfering with each other. Access to XMS memory is facilitated by an XMS driver such as Microsoft's HIMEM.SYS, which is supplied with Windows.