What is a
computer?
A computer
is an electronic device, operating under the control of instructions stored in
its own memory
What does a
computer do?
It performs
four basic operations- input, process, output, and storage.
Why is a
computer so powerful?
A computer
derives its power from its capability to perform the information processing
cycle with amazing speed, reliability (low failure rate), and accuracy; its
capacity to store huge amounts of data and information; and its ability to
communicate with other computer.
How does a
computer know what to do?
For a
computer to perform operations, it must be given a detailed set of instructions
that tells it exactly what to do. These
instructions are called a computer program, and software.
What are the
components of a computer?
The
processor, memory, and storage devices are housed in a box-like case called the system unit.
Input
devices
An input device in any hardware component that allows you to enter data,
programs, commands, and user responses into a computer.
The Keyboard
A keyboard
is an input device that contains keys you press to enter data into the
computer.
A stylus is
a small metal or plastic device that looks like a ballpoint pen, but uses
pressure instead on ink to write, draw, or make selections
The Mouse
A mouse is a
pointing device that fits comfortably under the palm o0f you hand.
With a
mouse, you control the pointer on the screen and make selections from the
screen.
System Unit
The system
unit is a case that contains electronic components of the computer used to
process data.
The mother
board is the main circuit board of the system unit
Processor
The
processor interprets and carries out the basic instructions that operate a
computer
The control
unit interprets the instructions.
The arithmetic\logic
unit performs the logical and arithmetic process
Memory
Memory
consists of electronic components that temporarily store instructions waiting
to be executed by the processor, data needed by those instructions and the
results of process data.
Kilobyte
equals approximately 1,000 memory locations and one megabyte equals
approximately one million memory locations. One gigabyte equals approximately
one billion memory locations. A memory location usually stores one character
such as a letter
Output
Devices
Output
devices make the information resulting from processing available for use
Printers
An impact
printer prints by striking an inked ribbon against the paper. Nonimpact Printers form characters by means
other than striking a ribbon against paper. Photo printers produce
photo-quality pictures and are ideal for home or small-business use.
Display
devices
A display
device is an output device that visually conveys text, graphics, and video
information. A monitor is a display device that is packaged as a separate unit.
Storage
devices
A storage
device is used to store instruction, data, and information when the y are not
being used in memory
Magnetic
Disks
Magnetic
disks use magnetic particles to store items such as data, instructions, and
information on a disk’s surface. Formatting is the process of dividing the disk
into tracks and sectors, so the computer can locate the data, instructions, and
information on the disk. A track is a narrow recording band that forms a full
circle on the surface on the disk.
Portable storage medium means that you can remove the medium form one
computer and carry it to another.
Hard disks
A hard disk
is a storage cevice that contains one or more
inflexible, circular platters that magnetically store data, instructions, and
information. A backup is a duplicate of a file, program, or disk that you can
use in case the original is lost, damaged, or destroyed.
Floppy disks
An older
form of magnetic storage is the floppy disk, an inexpensive portable storage
medium. A floppy disk drive is a device that can read from and write on a
floppy disk
CD-ROM-a type of optical disc that users can read but not write on or
erase.