User's Manual

246 Glossary
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FILE LOCATI ON: S:\SYSTEMS\Pebble\UG\A00\English\glossary.fm
DELL CONFI DENTI AL – PRELI MI NARY 1/29/03 – FOR PROOF ONLY
PXE — pre-boot execution environment — A W fM (Wired for Management)
standard that allows networked computers that do not have an operating system to
be configured and started remotely.
R
RAI D — redundant array of independent disks — A system of two or more drives
working together for performance and fault tolerance. RAID drives are typically used
on servers and high-end PCs.
The three most common RAID levels are 0, 3, and 5:
• Level 0: Provides data striping but no redundancy. Level 0 improves
performance but does not provide fault tolerance.
• Level 3: Same as Level 0, but also reserves one dedicated drive for error
correction data, providing good performance and some level of fault tolerance.
• Level 5: Provides data striping at the byte level and also stripe error correction
information, resulting in excellent performance and good fault tolerance.
RAM — random-access memory — The primary temporary storage area for
program instructions and data. Any information stored in RAM is lost when you shut
down your computer.
README FILE — A text file included with a software package or hardware
product. Typically, readme files provide installation information and describe new
product enhancements or corrections that have not yet been documented.
READ-ONLY — Data and/or files you can view but cannot edit or delete. A file can
have read-only status if:
• It resides on a physically write-protected floppy disk, CD, or DVD.
• It is located on a network in a directory and the system administrator has
assigned rights only to specific individuals.
REFRESH RATE — The frequency, measured in Hz, at which your screen's
horizontal lines are recharged (sometimes also referred to as its vertical frequency).
The higher the refresh rate, the less video flicker can be seen by the human eye.
RESOLUTI ON — The sharpness and clarity of an image produced by a printer or
displayed on a monitor. The higher the resolution, the sharper the image.
RFI — radio frequency interference — Interference that is generated at typical
radio frequencies, in the range of 10 kHz to 100,000 MHz. Radio frequencies are at
the lower end of the electromagnetic frequency spectrum and are more likely to have
interference than the higher frequency radiations, such as infrared and light.
ROM — read-only memory — Memory that stores data and programs that cannot
be deleted or written to by the computer. ROM, unlike RAM, retains its contents
after you shut down your computer. Some programs essential to the operation of
your computer reside in ROM.