There are two Main types of
computers:
The personal computer (PC) - This is the type of computer
has various part connected to it. You may have this type at home but more
commonly at school or in the office.
The Laptop - This is the type of computer has all the
various part all combined together. You may have this type at school or in the
office but more commonly at home.
The outside of your computer
The ‘box’ part of your
computer is called the system unit. It houses the various parts that act
together to make your computer work. Your system unit may be on your desktop
perhaps with the monitor on top, it may be a tower that sits on the floor,
saving space on your desktop or if it’s a laptop then it the bottom part that
has various buttons on it. You may also have a number of external peripherals
(hardware that plugs into your computer) — for example, an external modem (device used for connecting to the internet),
speakers, or a printer or scanner. Modems can be either an internal modem card
installed inside your computer or an external modem connected with cables to
your computer and phone line that is more commonly used today. Having an
external modem can have its advantages — you can see the modem’s light
indicating it is working. With an internal modem you would have to look at the
back of the computer to see the light flashing on the modem card.
The inside of your computer
Inside the system unit there
is a flat circuit board called the motherboard. Attached to this board are the
vital systems of the computer, including the
CPU (central processing unit) and the hard disk where your saved
information is usually stored.
The motherboard also houses
the ROM-BIOS chip (read only memory –
basic input output system). The BIOS is built-in software that determines
what a computer can do without accessing programs from a disk. The BIOS
contains all the code required to control the keyboard, display screen, disk
drives, and a number of miscellaneous functions. It bridges the gap between the
computer and the operating system program, and is responsible for communicating
with all the major systems, input and output devices and software when the ‘On’
button is pressed
Also inside the computer is
the RAM (the memory), comprising a
number of chips that ‘plug in’ to the motherboard. There will also be one or
more hard disks and, if appropriate to your system, a DVD or CD-ROM drive.
Depending on your system setup, you may also have other components such as an
internal modem for internet access and perhaps a network card to allow you to
connect to other computers..
Central Processing Unit
The CPU is a chip on the
motherboard of your computer. It is here that the processing required by your
task takes place. Processors vary in speed — the faster the chip, the faster
processing will be carried out. It is responsible for the running of all
programs, including the operating system, and uses a small portion of memory
allocated specifically to it to perform this and the millions of calculations
needed to keep the system operating. This function is highly complex as the CPU
must attend to the various needs of different parts of the system at the same
time.
The speed of the CPU is
expressed as megahertz (MHz), and
more recently gigahertz (GHz), and
the higher the rating, the faster the processor. The typical rating of a modern
system is around 3,400 MHz (or 3.4 GHz), but given the rate of change in the
computer world, this increases frequently.
The Connections
At the back of the computer
are the connection points where you can attach the various parts of your
computer, including the monitor, mouse and keyboard. These connection points
are called ports.
The serial and parallel
ports allow connection of peripheral devices such as a modem and/or a printer.
These will be labelled COM 1 and COM 2 for the serial ports, and LPT 1, and LPT
2 for the parallel. To connect peripheral devices such as a scanner or digital
camera, the USB (universal serial bus)
port may used. This port is designed for maximum communication efficiency and
ease of connection and is only available as standard on computers produced from
around 1998. Anything plugged into the computer base unit, for example, the
mouse, keyboard, monitor or a scanner or printer is called a peripheral device.
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