| Computer: |
A computer is a machine for manipulating data according
to a list of instructions. |
Computer is a system,
consisting of many components. Some of those components,
like Windows XP, and all other programs, are software.
The stuff you can actually see and touch, and would
likely break if you threw it out a fifth-story window,
is hardware. The system unit is the actual computer;
everything else is called a peripheral device. Computer's
system unit probably has at least one floppy disk drive,
and one CD or DVD drive, There's another disk drive,
called the hard disk inside the system unit. The floppy
drive and CD drive are often referred to as drives with
removable media or removable drives for short, because
you can remove whatever disk is currently in the drive,
and replace it with another. Computer's hard disk can
store as much information as tens of thousands of floppy
disks, so don't worry about running out of space on
hard disk any time soon. As a rule, you want to store
everything you create or download on hard disk. Use
the floppy disks and CDs to send copies of files through
the mail, or to make backup copies of important items. |
| |
| Computer Display: |
A monitor is an interface between the computer and the
operator. Although there are other interfaces the main
link to the operator is usually a CRT or TFT monitor.
To connect the computer's output to the monitor, the
video adapter converts the computers instructions to
a form that tells the monitor what to display. The CRT
or cathode ray tube, is the picture tube of a monitor.
The back of the tube has a negatively charged cathode.
The electron gun shoots electrons down the tube and
onto a charged screen. The screen is coated with a pattern
of red, dots that will glow when struck by the electron
stream. Each cluster of three dots is one
The image on the monitor screen is made up from thousands
of such tiny dots glowing on command from the computer.
The closer together the pixels are, the sharper the
image on screen. The distance between pixels on a
computer monitor screen is called its dot pitch and
is measured in Most monitors have a dot pitch of .28
mm or less.
|
| |
Random Access
Memory (RAM):
|
Random access memory is a type of data store used in
computers. It takes the form of integrated circuits
that allow the stored data to be accessed in any order
— that is, at random and without the physical
movement of the storage medium or a physical reading
head.
The word "random" refers
to the fact that any piece of data can be returned quickly,
and in a constant time, regardless of its physical location
and whether or not it is related to the previous piece
of data. This contrasts with storage mechanisms such
as tapes, magnetic disks and optical disks, which rely
on the physical movement of the recording medium or
a reading head. In these devices, the movement takes
longer than the data transfer, and the retrieval time
varies depending on the physical location of the next
item. |
| |
| Hard Disk: |
A hard disk (commonly known as a HDD (hard disk drive)
or hard drive (HD) and formerly known as a fixed disk)
is a non-volatile storage device which stores digitally
encoded data on rapidly rotating platters with magnetic
surfaces. Strictly speaking, "drive" refers
to an entire unit containing multiple platters, a read/write
head assembly, driver electronics, and motor while "hard
disk" refers to the storage medium itself. Hard
disks were originally developed for use with computers.
In the 21st century, applications for hard disks have
expanded beyond computers to include digital video recorders,
digital audio players, personal digital assistants,
and digital cameras. In 2005 the first mobile phones
to include hard disks were introduced by Samsung Group
and Nokia. The need for large-scale, reliable storage,
independent of a particular device, led to the introduction
of configurations such as RAID, hardware such as network
attached storage (NAS) devices, and systems such as
storage area networks (SANs) for efficient access to
large volumes of data.
|
| |
| Computer Keyboard: |
A computer keyboard is a peripheral partially modeled
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 key. |
| |
| Mouse: |
A mouse is a computer pointing device; it is designed
to detect two-dimensional motion relative to its supporting
surface and consists of a small case, to be held under
one of the user's hands, and one or more buttons. It
sometimes features other elements, such as "wheels",
which allow the user to perform various system-dependent
operations, or extra buttons or features can add more
control or dimensional input. The mouse's motion typically
translates into the motion of a pointer on a display.
The name mouse, coined at the Stanford Research Institute,
derives from the resemblance of early models to the
common eponymous rodent.
|
|
|
|
