Welcome to Exploring Computing.
Today's video is computer hardware, anatomy of a laptop.
So in this video, we're going to take apart
iBook G4, which was donated by one of my former TAs.
Normally, we take this apart, and I give one of the TAs
a video camera, which they point at the laptop as we dissect it,
and we project from that camera onto the classroom's
main screen so everybody can take a closer
look at what's actually going on,
and I pass around the parts.
Unfortunately, that wasn't an option.
And I also don't actually have access to the laptop itself.
So these are all old photographs.
Currently, the gates building is locked, and none of us
are allowed in.
So let's go ahead and take a look at our laptop here.
So this is an iBook G4.
It's about 15 years old.
You can also see it's got a serious case of what
is sometimes referred to as keyboard plaque.
I mention this because some of you
are probably looking at this thinking, Patrick,
that's kind of gross.
And it is, and honestly, I should probably
take an industrial-strength solvent to it
and do some cleaning because, as we'll see in a minute,
this laptop is clearly never going
to be used anyway, so it could use some serious cleaning.
And I will have to say this is one of those cases
where Apple's white motif here is probably not
doing us any favors.
Anyway, so what we're going to do
is we're going to take off the keyboard,
take off the gross keyboard, and it turns out
that this particular laptop is upgradable.
And this is something that some of the larger laptops
have the ability to change and modify some of the parts.
The nice slim, sleek laptops do not have--
generally, do not have that ability.
Usually, the parts are not set up to allow for modularity.
Instead, they're designed to be as compact as possible,
and generally, they're not serviceable.
OK, so this particular laptop--
this is old enough so that it did not actually
originally come with a Wi-Fi.
This was an option, and so you could take off the keyboard,
and there was a place where you could slip in a Wi-Fi card,
and there's the Wi-Fi card right there.
Not shown right here because there's
actually a metal shield that goes under this.
We'll talk about that in a second.
And then, underneath where the Wi-Fi goes,
and you can see that this one actually did have a Wi-Fi card.
That's what's sitting there.
It's been pulled out.
And then, underneath that, that is actually computer memory,
so I could go ahead and add RAM to this particular laptop.
Notice the metal sheeting that is covering
everything other than the airport extreme
Wi-Fi card and the memory.
We're going to go ahead and flip this over.
And in the corner there, the missing part that's
actually where the battery goes.
But the main thing that I wanted to show you
here is if we pull off the back, again
you can see this metal sheeting all around the laptop.
So this is basically going to completely surround the laptop.
This is designed as electromagnetic shielding,
and it's designed to reduce the amount
of electromagnetic radiation that comes out of the laptop
or that goes into the laptop because we don't want
the laptop to interfere with other electronic devices
in the area.
So, for example, you may have seen on various television
shows the idea that if you've got
those rabbit ear antennas on your television,
and you're trying to get the television to work properly.
If you've got some sort of a electromagnetic motor
or sometimes electronic device, it
can go ahead and interfere with it.
And so, this metal sheet that goes
all around the entire laptop that
is designed to reduce the amount of electromagnetic radiation
coming out of the laptop and prevent problems like that.
And if we take off the sheeting here on the back,
you can see that's what's underneath it.
We're going to be talking about this green motherboard
here on the left in a couple of minutes, but let's go ahead
and flip it over first.
OK, so this is the top of the laptop.
What you see on the inset here is
the electromagnetic shielding that
is supposed to go on the top of the laptop,
but it's actually been removed here.
And this inset is obviously from another photograph.
OK, see, here's all the different parts right here,
and there are a couple parts that I
think are worth mentioning here, and we're
going to take a quick look at them in the overview,
and then we're going to go into more detail on each of these.
So here's a tighter in shot.
That little U-shaped metal object right there that
is actually the Wi-Fi shield.
So that is what it was supposed to be
under the Wi-Fi card in the previous shot
when we had just opened up the keyboard.
I don't know why it wasn't in the photograph,
but it wasn't in the photograph, but that actually
goes between the memory, which was accessible.
So you would take off the keyboard.
There would be the Wi-Fi slot.
Then there would be this Wi-Fi shield,
and then underneath the Wi-Fi shield would be the memory.
And the Wi-Fi card is outside of a shielding
because it does need to send signals.
OK, next to it is something called the heat sink.
We'll talk in more detail about that in a minute.
And then, underneath or just below on the photograph,
just below the heat sink, is the hard drive or hard disk,
and it's actually sitting in the location
where the battery is supposed to go.
I don't know why it's sitting there
in this particular photograph.
The correct location for it is in the far left,
and that orange cabling there is actually how data
gets on and off the hard drive.
That's supposed to be connected to the hard drive.
And then, that whole area on the left side
that's the motherboard, and we'll
take a look at each of these in a little bit more depth.
And there's the backside view, and again,
that motherboard that we're seeing
on the left of the main photograph
is the exact same board as shown in the inset on the backside
view of the laptop.
OK, so this is a hard drive or hard disk.
The distinction between the drive and the disk
isn't particularly important in this case,
but here's the distinction.
The drive is the thing that the disk is contained
within since a hard drive has the disk permanently in it,
hard drive and hard disk are largely synonymous,
but you can think of, for example, I
have a Blu-ray drive, which is a device
that I put Blu-ray disks into.
So, in that case, the drive is the thing
that you put the disks into, and you have
a variety of Blu-ray disks.
But the hard drive the disk is permanently stuck in it,
so it's more or less the same.
You can see the disk itself here.
It consists of a number of different platters.
We're reviewing the top platter right here,
and those platters spin around at very high speeds.
The faster the speed that the platter spins around,
the faster we can access our data and the more expensive
the disk.
These are the read/write head.
They're supposed to be--
you can kind of see the sort of V-shape
heading in underneath the platter.
There's actually supposed to be another one of those
on the top, and that got bent off and broken off
during one of our demonstrations,
so that is no longer with us.
But basically, the tip, which is not shown it's
underneath the desk there.
That's where the magnetic read/write head goes,
and that whole assembly moves in and out.
And by moving it in and out and spinning the disk around,
we're able to access every individual part of the platter,
and we can magnetize it, or we can
read how that section of this is magnetized,
and that's how we're starting our bit on this particular type
of device.
So some of you may be like, why are we looking at a hard disk.
This is old technology.
Actually, it turns out depending on what you're trying to do.
Hard disks may still be more practical
than SSD drives just because they are cheaper per byte,
so if you've got a lot of bytes, you
may be better for the hard disk.
So people will use hard disks if maybe they've
got a lot of video, say they're recording lots of lectures
remotely, or probably a better example is they use it
for things like video surveillance, where
you have a constant stream of video coming in.
You want to store that all.
Anything that requires a lot of data storage,
it's going to be a lot cheaper to use
a hard disk or hard drive than it will
be to use a solid-state drive.
Now, here's a solid-state drive.
I don't actually have pictures of these.
I don't have an SSD at this point
that I'm prepared to sacrifice for her demos,
but it turns out there are a couple of shots on Wikimedia
Commons, so credits for these photographs
will be at the end of the presentation.
So this is what the solid-state drive looks like,
and you can see the top left view is the external view,
and the bottom right view is when you actually
pull the covers off.
That's what's inside, and you can
see it looks very similar to the motherboard.
We'll be talking about this in a couple of minutes,
but that's a printed circuit board
with a bunch of computer chips on it.
So basically, the SSD is pretty boring,
is just a whole bunch of computer chips, which actually
is why, in many respects, the SSD is
better than the hard drive.
The chips are much, much faster than mechanical device
and also it's less susceptible to things like vibration.
So like I would always be nervous if my laptop had
a hard drive in it if I tried to use the laptop while I
was moving it.
But with an SSD, there's no moving parts,
so it's just more reliable and less things to concern yourself
with.
Let's go back to our overview here,
and there's a motherboard on the left.
And here's a closer view of the motherboard.
In the previous shot, the heat sink
was not in the proper position, and now the heat sink
is in the proper position.
That's that big metal thing in the middle there.
You can also see the memory chips just to the right of it.
And we're going to go ahead and take off the heat sink here.
And so, let's talk a little bit about heat sinks.
If you look at the image here, you
can see that we've got the heat sink,
and then up in the top right-hand corner that's
actually a fan, and so what the heat sink is doing
is it's actually on top of the chips on the motherboard that
generate the most heat.
And you want a heat sink that is heat conductive,
so some sort of metal that can conduct heat really well.
And you wanted to have the maximum surface area,
and then you want to blow fans on it
to try and conduct the heat away.
So maximum surface area to maximize
the amount of heat that can come off of it,
and then some sort of a fan system.
And so, what we're seeing here is
you can see that heat sink from the laptop that's
on the left-hand side of this image here.
It actually does connect up to another big metal
section, which is right next to where the fan was.
And then, on the right side, this
is an example of a desktop computer's heat
sink, very large, often quite heavy.
We're going back to the motherboard here,
and this is underneath the motherboard.
And so, we've got a couple of important chips here,
but let's talk about the motherboard itself first.
So the motherboard itself is what we refer to
as a printed circuit board.
And we saw a printed circuit board a minute ago with the SSD
drive.
So the printed circuit board that it's basically got that
green substrate that everything's on that is
non-conductive, meaning that electric signals cannot pass
through the green substrate.
And what we do is, on top of the green substrate,
we etch or laminate on thin lines of something that
can conduct electricity, and that's
how we send signals and electricity
through our computer.
And what I've got here is these two modules down.
These two insets down below are actually
showing part of a memory module.
And I'm using these because I had the photographs,
and normally, we actually take the motherboard
and pass it around so people can kind of
see what it really looks like.
Obviously, we can't do that.
But I thought these two photos did a good job, kind
of giving a closer, tighter and look at what the printed
circuit board actually looks like.
So again, there's that green substrate,
and then we've got some computer chips attached
to the printed circuit board.
And then, you can see we've got these fine etched
on or laminated on metal lines going through,
and that's actually where our electric signals go.
So going back to the motherboard in the top,
we have the CPU or central processing unit.
And then, at the bottom, we have the graphics chip.
These both generate a tremendous amount of heat,
and so that's why we've got the heat sink over them.
Here's a shot of central processing
unit from a desktop computer.
We can't actually take the laptop CPU out,
so this is one of my old office computers CPUs.
CPUs for desktop computers are often upgradeable,
so they're designed to actually pull out.
There's a socket that you can actually
pull the CPU out of and replace it with a different CPU.
Laptops are generally not designed for that,
and the CPU is going to be soldered directly
onto the motherboard.
But I really like this shot.
It really shows how the information
gets on and off of the CPU.
So we see all these pins here, and each of these pins
is being used for one of several purposes.
First of all, there's a couple of pins
in there just for power, so our central processing unit
does need power.
I should also mention so this is actually
the package surrounding the actual computer chip.
So we can't actually see the computer chip.
It is inside the ceramic package.
There are thin wires connecting the actual chip,
which is again inside what we're looking at here.
There are thin wires connected to each of the pins
that we're actually looking at here,
but these pins are used to get power, data,
and address information, and control information
on and off the CPU.
So imagine what we talked about earlier, we've got the CPU.
It's connected to main memory.
The CPU needs to access data from main memory,
and so a whole bunch of these pins
are going to send address information.
So I'm going to set the address pins on this saying, hey,
this particular sequence of bits I'm about to send down
these address pins, that's the address for the particular byte
in memory that I want to access.
And then, either if I'm doing a read operation,
either memory is going to send the bits
at that particular memory location down
and through the data pins, and I'm
going to store that information in the CPU I can access it,
or I'm going to go the other way,
and the CPU is going to say, OK, I've
got some information stored in internal data
register in the CPU, I need to store that memory now.
And so, I'm going to set the address
pins to the address of the bytes in memory
that I want to store this information in,
and I'm going to send the data through the data pins.
So there's a whole bunch of pins as we've
moved to from 8-bit computer to 16-bit computing
to 32, 64 bits.
We need more and more pins, and so that's
what all those pins are doing.
And then, here's our overview again.
And the last thing I wanted to mention is just the memory.
So, on the right, we see the memory for the laptop,
and on the top left, we've see a memory
for our desktop computer.
These are what I refer to as memory modules.
There are different types of memory modules.
The main point I wanted to make here
is notice how many computer chips there are here.
So on the laptop, you can count there's four chips there.
And then, for the desktop, there's eight.
Often there's another set of chips underneath,
so it's possible with the laptop we've got four on top.
There might be another four underneath.
And with the desktop, we've got eight.
There might be another eight, but again,
notice these are all powers of two
because everything inside the computer
is done with powers of two, and in fact,
as we saw previously with those pins coming out of the CPU,
those pins could be on or off.
The address pins could be on or off,
and so those are going to drive our binary numbers
and our powers of two inside the computer.
OK, so that's our last slide.
I hope you've enjoyed our little look at what's actually
going on inside of a laptop.