Back to Contents PageGlossaryDell™ Latitude™ D420 User's GuideTerms in this Glossary are provided for informational purposes only and may or may not describe features included with your particular computer.AAC — alternating current — The form of electricity that powers your computer when you plug the AC adapter power cable in to an electrical outlet.ACPI — advanced configuration and power interface — A power management specification that enables Microsoft® Windows® operating systems to put acomputer in standby or hibernate mode to conserve the amount of electrical power allocated to each device attached to the computer.AGP — accelerated graphics port — A dedicated graphics port that allows system memory to be used for video-related tasks. AGP delivers a smooth, true-colorvideo image because of the faster interface between the video circuitry and the computer memory.ALS — ambient light sensor.antivirus software — A program designed to identify, quarantine, and/or delete viruses from your computer.APR — advanced port replicator — A docking device that allows you to conveniently use an external monitor, keyboard, mouse, and other devices with yourportable computer.ASF — alert standards format — A standard to define a mechanism for reporting hardware and software alerts to a management console. ASF is designed tobe platform- and operating system-independent.Bbackup — A copy of a program or data file on a floppy, CD, DVD, or hard drive. As a precaution, back up the data files from your hard drive regularly.battery — A rechargeable internal power source used to operate portable computers when not connected to an AC adapter and an electrical outlet.battery life span — The length of time (years) during which a portable computer battery is able to be depleted and recharged.battery operating time — The length of time (minutes or hours) that a portable computer battery holds a charge while powering the computer.BIOS — basic input/output system — A program (or utility) that serves as an interface between the computer hardware and the operating system. Unless youunderstand what effect these settings have on the computer, do not change them. Also referred to as system setup program.bit — The smallest unit of data interpreted by your computer.Bluetooth® wireless technology — A wireless technology standard for short-range (9 m [29 feet]) networking devices that allows for enabled devices toautomatically recognize each other.boot sequence — Specifies the order of the devices from which the computer attempts to boot.bootable CD — A CD that you can use to start your computer. In case your hard drive is damaged or your computer has a virus, ensure that you always havea bootable CD or floppy disk available. Your Drivers and Utilities CD or ResourceCD is a bootable CD.bootable disk — A disk that you can use to start your computer. In case your hard drive is damaged or your computer has a virus, ensure that you alwayshave a bootable CD or floppy disk available.bps — bits per second — The standard unit for measuring data transmission speed.BTU — British thermal unit — A measurement of heat output.bus — A communication pathway between the components in your computer.bus speed — The speed, given in MHz, that indicates how fast a bus can transfer information.byte — The basic data unit used by your computer. A byte is usually equal to 8 bits.CC — Celsius — A temperature measurement scale where 0° is the freezing point and 100° is the boiling point of water.cache — A special high-speed storage mechanism which can be either a reserved section of main memory or an independent high-speed storage device. Thecache enhances the efficiency of many processor operations.L1 cache — Primary cache stored inside the processor.L2 cache — Secondary cache which can either be external to the processor or incorporated into the processor architecture.