In this video, we'll
examine the different elements
which constitute a computer,
from the most external
components you all know
to the most internal which
allow it to work.
So here is a classic computer,
here we have the big box we call the
computer system unit, a monitor,
a keyboard,
a mouse,
and an external hard drive.
These last components are called
external peripheral devices.
They can be input devices,
like the keyboard, the mouse,
or a camera or a scanner.
They can also be output devices,
like a monitor or a printer.
And there are input/output devices,
like the external
hard drive for instance,
with which we can read information at the
input and write information at the output.
All these external peripheral devices
are plugged into the back of the computer
into sockets named ports.
So I've turned the computer
around and you can see here
all the connections made at
the back of the computer system unit.
Most of these connections are provided
by sockets called ports.
Here we can see USB ports
for the external hard drive,
but also for the mouse.
Here a PS/2 port for the keyboard,
and here DVI ports to
which the monitor is plugged.
But there are also other ports,
like the FireWire ports,
and here a specific port,
an Ethernet port,
which demonstrates that the
Internet can also be seen
as a peripheral device
external to the computer.
Now let's look at what happens
inside the computer system unit.
There are many things inside
this computer system unit,
but let's begin with
the connection to the outside.
Here we have the power supply which
is plugged into this power supply unit.
All the cables of a certain color
will carry electricity
to the different internal
components of the computer.
The monitor here is plugged
into this element
which is the video card.
At last, the other elements, the keyboard,
the mouse and the hard drive are
plugged into this big plate
we see at the bottom that
is called the motherboard.
The different elements here
are thus the power supply,
the video card and the
motherboard at the bottom.
But there are other elements,
here we have a DVD player/burner drive
and a floppy disk drive and we
can see they're powered.
And here we have two hard drives.
Actually, these different elements
are like peripheral devices,
but internal this time.
We can see they are powered,
and this blue cable here,
or this grey ribbon here
connect them to the motherboard
thanks to internal ports, this time.
We can remove them to
better see the computer core.
I will also remove this big
block here which consists of a fan
and of a cooling system for
the central processing unit (CPU).
That's it, so I've removed the
DVD burner and the floppy disk drives,
as well as the power supply.
The big cooling block,
here, I can remove it,
you can see the CPU below
and the remaining element is a fan.
I've also removed the two
hard drives, I've kept one
to show you that it's connected
to the motherboard with a port.
But there's more, we can
see the motherboard a little better,
but there are still circuits,
I've already talked about some of them.
Here the video card and, here, a card
with which the FireWire ports can be controlled.
So I'll remove those elements
which are still not part
of the computer core.
We're almost done and here are
the essential elements of a computer
with hard drives which
are the mass storage,
but I can remove them,
and printed circuit boards here,
which I can also remove,
it's the random-access memory, the RAM.
That's it, we've removed all the
internal peripheral devices
and there are two elements left.
Here, the motherboard and in particular
little electronic circuits here
with which the different ports
we could see from outside are managed,
they're called controllers.
And finally, the only element
that really matters
is this, here, the CPU.
Here is the heart of
the computer, it's the CPU.
I open the protection cover
and I can remove the CPU.
We can see here it's connected
to the motherboard
with numerous little legs
that act like ports.
So this CPU is really
the central unit,
the essential computing unit
of the computer.
Even inside the CPU, we will
find a specific design,
with memory areas
named caches,
and several computer units,
usually many,
which work simultaneously
to be more efficient.
So if I zoom out on
the computer now,
we can see the central
element that is the link
between all the other elements
of the computer, it's the motherboard.
To it is first
connected the CPU,
the fundamental element
which communicates via
the motherboard with
internal peripheral devices
such as RAM or hard drives,
the video card, the DVD burner drive,
but also with external devices,
through port controllers
which can be seen at the
back of the computer.