Lesson video

Hello I'm Kash, your computer science teacher for the computer systems unit.

Welcome back to lesson two where we have a look under the hood at the physical components that a machine requires in order to execute any programme.

You're going to need a pen, some paper and you're going to need to remove any distractions that will stop you from focusing 'cause we want to make the most out of this lesson so once you've done that, lets continue.

In this lesson, you will learn about the hardware components used in computing systems and explore how all computing systems are similar in structure.

Okay, so let's begin with a recap What's the main task Okay, so let's begin with a recap from last lesson, What is the main task of a general-purpose computing system? Is it A.

The main task is to execute programmes.

B.

There is no main task.

It can perform any task prescribed by a programme.

Is it C.

The main task depends on the system.

Different systems may perform a different main task.

Or lastly, is it D.

The main task depends on the user.

Different users may need the system to perform a different main task.

Have a think about it.

Okay, let's have a look at the answer.

Even though each answer had a little bit of truth in it, the main or the correct answer is A.

The main task is to execute programmes.

So at the core of it, the purpose or the main task of a general-purpose computing system is to execute programmes.

A machine playing noughts and crosses.

In the previous lesson, you ironed out instructions mechanically to play a game of noughts and crosses.

Now, what do you think it would take for a machine to be able to execute that programme? Write your answers down.

Okay.

So in order for a machine to execute that programme, we're going to need three things.

Number one, we need to look at the language.

It needs to understand the programme.

Number two, input and output.

It needs to read the board and then also be able to write on it.

And lastly, hardware.

Internally, it needs the components that will allow the machine to follow the instructions.

The physical components of a computing system are called hardware.

Hardware is any component of a computing system that you can actually touch.

For example, this keyboard or this mouse, you can physically touch them, hence they are hardware.

Now, last lesson we actually looked at the programmes and different types of software, so the programmes of a computer system are called software.

Task 1, check the specs.

Specs, or specification, is a table of hardware components and technical characteristics.

Your worksheet contains specs for a range of modern computing devices.

Now, once you're done, you need to ask yourselves, what the components that are present in every one of these computing systems? Pause the video to complete your task.

Resume, resume once you are finished.

Check the specs - solution.

Let's see how you guys got on.

How did you get on? The purpose of this task was to get you thinking about the components that all computing systems have in common.

So, from the processor to memory to storage to communication, all the devices had them components.

Now, all the components which has input and output and connections are essential.

Without input, there's no way of those giving information to that computer system.

Computer systems work in a way where we provide that input or they get that input from somewhere, they then process that input and then they output the results of that processing.

Insight.

Diverse computing systems have strikingly similar components.

All computing systems are similar in structure.

So from a games console to a laptop to a mobile phone, they all have similar components.

Just like what we did in the previous task.

Now, let's examine what the components are, what they do, and how they function together in order to execute programmes.

The first component that we are going to look at is storage.

So, the storage, or secondary memory, is the set of components that stores programmes and data.

Storage is persistent: it retains its contents when the power is off.

So, it listens, it stores that information long term.

Can you name a few common storage devices? Write some down.

Okay, let's see if you got some of these that we've got.

Hard disc drives, solid-state drives, USB flash drives or sticks, and SD cards.

Storage technology evolves over time.

But, the concept of storage is constant.

What we mean by that is the different types of devices that you're going to store your information on will change, but we always need to store information.

So for example, quite a long time ago, one of the storage devices was called a floppy disc or a floppy drive.

The storage capacity was only 1.

44 MPS, so all that meant was in today's day and age, that device wouldn't even be able to storage a selfie.

However, back then, it would store documents and data quite easily.

Let's have a look at some of the images.

We've got a hard disc drive, a solid-state drive, an optical disc, an SD card, and a USB stick.

Here's a diagram to explain what's going on.

So, there's our storage, and what does it store? Programmes and data.

Next, let's move on to main memory.

The main memory is the component that stores the programmes and data currently in use.

So once you're using that particular programme, it's storing that data.

So it's short term, as opposed to long term, what we discussed previously.

This memory is volatile.

The contents are lost when the power is off.

Terminology: the main memory is commonly referred to as a RAM, random-access memory.

On the right hand side, you can see a picture of what it looks like.

This is what the main memory looks like in desktops and laptops.

Sometimes, the memory is integrated with other components, rather than being a separate component.

You'll notice that that's quite common with quite a few components, just like the CPU, that we are going to be moving on to next.

How it works with other components.

When a programme must be executed, it's loaded from storage in memory, along with the data required.

So, we load that information, any new or modified data must be saved from memory to storage.

So, just to recap, memory saves that information or what we're doing in terms of short term but then storage saves it long term.

Here's a diagram explaining that whole process.

So, if we look at it from the bottom, storage, what's it storing? We've got programmes and data.

They then load it into memory, and then once we're done and the data's been processed, we then save it into storage.

Processor.

The processor is the component that executes programme instructions.

An instruction may: perform arithmetic or logic operations on data, perform input/output of data, or control programme flow.

The processor is commonly referred to as the CPU, or the brains of the computer.

On the right hand side, this is what the processor looks like in desktops and laptops.

As we said previously, some components are integrated, and the CPU could be one of them.

So, for example, if we get something such as a GPU, a graphical processing unit.

How it works with other components.

Instructions are fetched one by one from memory into the processor, along with any additional data that's required.

The processor decodes and executes each instruction.

What we mean by that is it understands what needs to be done and then it actually does that particular instruction or executes that particular instruction.

Any resulting data is moved into memory.

Here's an example.

So we've got the decoding taking place.

And the executing.

And then we're finally moving it into memory.

To help you understand that concept better, we're going to use an analogy.

So on the left hand side, we've got a lovely lady doing some knitting.

Knitting patterns, yarn supplies, half-finished and finished projects are kept on the shelves.

This is the storage for programmes and data.

When the knitter works on a project, the knitting pattern and materials are transferred from that supply to the work area, where she's got quick access to them.

This is the memory, when the programme on the execution is stored temporarily along with the required data from the processor.

The knitter reads from the knitting pattern one instruction at a time, and carries out the instruction, operating on the material at hand.

The knitter is the processor.

What does it do? Computing systems exchange information and form networks using communication components.

Programmes and data are transferred between computing systems when required.

This allows input to be obtained remotely, data to be stored on remote systems, and programmes to be executed remotely.

Here we have a diagram that explains that concept.

Next, name different ways for computing systems to communicate.

Hint: Think about networks.

Have a go, write some down.

Okay.

Computing systems interact with the user and their surroundings through devices for input and output.

Input: data received by a system, and output: data transmitted from a system.

As we can see on the right hand side.

So the input and output is in the middle where it interacts with user and surroundings, at the same time it can transfer data and programmes.

Name a few common input devices.

Have a go.

Let's see if you get the ones that we've got on the list here.

Okay, are you ready? Let's have a look.

Some of the common input devices are a keyboard, a mouse, a camera, or microphone.

Each of these devices is taking in that information and data is received by a system.

Name a few common output devices.

Have a go, let's see what you get.

So, we've got a screen, speakers, projector, or printer.

There's just some of the options that we've got.

Did you get any of them? Okay, our last and final task.

Task 2, wearable computing.

Google Glass is a wearable computing system.

Use the worksheet to the label its components.

Using the worksheet, complete Task 2.

Resume once you are finished.

I hope from this lesson you've got a better idea of the components that are used within computer systems. We'd really like to see the work that you produced.

So, ask a parent or caregiver if you can, and share your work on Instagram, Facebook, or Twitter.

Thank you very much for your time today.

And, well done on the hard work and all the effort that you put in.

See you again soon.

Goodbye.