Abbreviation of central processing unit, and pronounced as separate letters. The CPU is the brains of the
computer. Sometimes referred to simply as the
processor or central processor, the CPU is where most calculations take place. In terms of computing power, the CPU is the most important element of a
computer system.
On large machines, CPUs require one or more
printed circuit boards. On
personal computers and small
workstations, the CPU is housed in a single
chip called a
microprocessor.
Two typical components of a CPU are:
The
arithmetic logic unit (ALU), which performs arithmetic and logical operations.
The
control unit (CU), which extracts
instructions from
memory and decodes and
executes them, calling on the ALU when necessary.
Also see
All About Dual-Core Processors in Webopedia's "
Did You Know...?" section.
RAM
Pronounced ramm, acronym for random access memory, a type of computer memory that can be accessed randomly; that is, any byte of memory can be accessed without touching the preceding bytes. RAM is the most common type of memory found in computers and other devices, such as printers.
There are two basic types of RAM:
dynamic RAM (DRAM)
static RAM (SRAM)
HARDDISK
A hard disk drive (HDD), commonly referred to as a hard drive or hard disk,
[1] is a
non-volatile storage device which stores digitally encoded data on rapidly rotating
platters with
magnetic surfaces. Strictly speaking, "drive" refers to a device distinct from its medium, such as a tape drive and its tape, or a floppy disk drive and its floppy disk. Early HDDs had removable media; however, an HDD today is typically a sealed unit with fixed media.
[2]HDDs were originally developed for use with
computers. In the 21st century, applications for HDDs have expanded beyond computers to include
digital video recorders,
digital audio players,
personal digital assistants,
digital cameras, and
video game consoles. In 2005 the first
mobile phones to include HDDs were introduced by
Samsung and
Nokia. The need for large-scale, reliable storage, independent of a particular device, led to the introduction of configurations such as
RAID arrays,
network attached storage (NAS) systems and
storage area network (SAN) systems that provide efficient and reliable
KEYBOARDA computer keyboard is a
peripheral partially modelled after the
typewriter keyboard. Keyboards are designed for the input of text and characters and also to control the operation of a
computer.
Physically, computer keyboards are an arrangement of rectangular or near-rectangular buttons, or "keys". Keyboards typically have characters
engraved or
printed on the keys; in most cases, each press of a
key corresponds to a single written
symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence; other keys do not produce any symbol, but instead affect the operation of the computer or the keyboard itself. See
input method editor.
Roughly 50% of all keyboard keys produce
letters,
numbers or
signs (
characters). Other keys can produce actions when pressed, and other actions are available by the simultaneous pressing of more than one action
POWER SUPPLYPower supplies in today's computers are known as SWITCHMODE or Switching Mode power supplies and require a load to continue to operate after being switched on (the term switching mode actually applies to the technique of A/C to D/C conversion and not to the power up action). This load is provided by a 10 watt, 10 ohm wire wound load resistor (sandbar - about $0.80 at Radio Shack) across the +5 volt supply. Some inexpensive power supplies may fail if forced on without a load. The sandbar has been zip tied to the case with a small amount of heat sink compound applied. Without cooling, the resistor will get very hot and may fail prematurely. With this arrangement, the resistor will remain barely warm to the touch. Be warned that many of the heat sink greases can be quite toxic and any excess should be cleaned up and disposed of properly. Also be sure to thoroughly clean your hands and tools after use. While most heatsink compounds are rated to 160 to 170 C, some may dry out over time and their effectiveness will diminish -- a periodic check for good contact between the case and resistor is a recommended practice.
MOTHER BOARD
MOTHER BOARD
motherboard is the central or primary
circuit board making up a complex electronic system, such as a modern
computer. It is also known as a mainboard, baseboard, system board, or, on
Apple computers, a
logic board, and is sometimes abbreviated as mobo.
[1]The basic purpose of the motherboard, like a
backplane, is to provide the electrical and logical connections by which the other components of the system communicate.
A typical
desktop computer is built with the
microprocessor,
main memory, and other essential components on the motherboard. Other components such as
external storage, controllers for
video display and
sound, and
peripheral devices are typically attached to the motherboard via
edge connectors and cables, although in modern computers it is increasingly common to integrate these "peripherals" into the motherboard
MOUSE
MOUSE
mouse (plural mice) is a
rodent that belongs to one of numerous
species of small
mammals. The best known mouse species is the
common house mouse (Mus musculus). It is found in nearly all countries and, like the laboratory mouse, serves as an important
model organism in biology, and is also a popular
pet. The American
white-footed mouse (Peromyscus leucopus) and the
deer mouse (
Peromyscus maniculatus) also sometimes live in houses. These species of mice live
commensally with humans.
Although they may live up to two years in the lab, the average mouse in the wild lives only about 5 months, primarily due to heavy
predation.
Cats, wild
dogs,
foxes,
birds of prey,
snakes and even certain kinds of
insects have been known to prey heavily upon mice. Nevertheless, due to its remarkable adaptability to almost any environment, and its ability to live commensally with humans, the mouse is regarded to be the third most successful mammalian species living on Earth today, after humans and the
rat.
Mice can be harmful
pests, damaging and eating
crops and spreading
diseases through their
parasites and
feces. In the Western United States, breathing dust that has come in contact with mouse feces has been linked to the deadly
hantavirus. The original motivation for the domestication of
cats is thought to have been for their predation of mice and their relatives, the
rats.