180 Glossarypixel — A single point on a video display. Pixels are arranged in rows and columns tocreate an image. A video resolution, such as 640 x 480, is expressed as the number ofpixels across by the number of pixels up and down.POST — Power-on self-test. Before the operating system loads when you turn on yoursystem, the POST tests various system components such as RAM and hard drives.processor — The primary computational chip inside the system that controls theinterpretation and execution of arithmetic and logic functions. Software written forone processor must usually be revised to run on another processor. CPU is a synonymfor processor.protected mode — An operating mode that allows operating systems to implement:• A memory address space of 16 MB to 4 GB• Multitasking• Virtual memory, a method for increasing addressable memory by using the hard driveThe Windows 2000 and UNIX 32-bit operating systems run in protected mode.MS-DOS cannot run in protected mode.PS/2 — Personal System/2.PXE — Preboot eXecution Environment. A way of booting a system via a LAN(without a hard drive or bootable diskette).RAC — Remote access controller.RAID — Redundant array of independent disks. A method of providing dataredundancy. Some common implementations of RAID include RAID 0, RAID 1,RAID 5, RAID 10, and RAID 50. See also guarding, mirroring, and striping.RAM — Random-access memory. The system’s primary temporary storage area forprogram instructions and data. Any information stored in RAM is lost when you turnoff your system.RAS — Remote Access Service. This service allows users running the Windowsoperating system to remotely access a network from their system using a modem.readme file — A text file, usually shipped with software or hardware, that containsinformation supplementing or updating the product’s documentation.read-only file — A read-only file is one that you are prohibited from editing ordeleting.ROM — Read-only memory. Your system contains some programs essential to itsoperation in ROM code. A ROM chip retains its contents even after you turn off yoursystem. Examples of code in ROM include the program that initiates your system’sboot routine and the POST.ROMB — RAID on motherboard.
