Lesson video

Hey there, I'm Mac, your computing teacher, and welcome to the computer systems unit.

In this unit, you're going to be learning all about the hardware and software that make up your computer.

In this first lesson, you're going to be covering how to classify computer systems as either general purpose or embedded.

And also, looking at some key pieces of software that keep your computer running.

For this lesson, you're going to need a pen and a notepad to take notes while you're learning.

Also make sure to remove all distractions, wherever possible, including turning off your mobile phone, which reminds me.

All right, I've turned my phone off.

I've also got my bottle of water here.

So, make sure you get some refreshment if you need it, as well.

If you want to pause the video and go get all the things you need, I'll be here when you get back.

In this lesson, you will identify computer systems, as well as explaining the role of system software, which is those key pieces of software I was talking about earlier.

And then we're going to describe one particular piece of system software called Operating systems. So, let's start off with identifying some computer systems. Before we saw anything, really, we should know, what is a computer system? And a computer system is a combination of the hardware, both internal, inside of your computer and peripheral, outside your computer and software, that work together to make up your computer.

I'd like you to pause the video here and have a go to writing, your best answer to this question, what is a computer? If you want to pause the video here, write your answer, and play when you're ready.

Welcome back, how did you do? Wow, let's have a look at my answer and we'll see how it compares.

So, a computer is a programmable device that takes in data, processes it into a piece of useful information and then outputs our information so that it can be used by a user or maybe even another computer.

You might have seen a diagram similar to this one before, and we call this the Input-Processing-Output Cycle.

So, we take in data, we process it, we do something to it, and then usually that involves interacting with storage in some way, both saving files and grabbing files from storage.

And then, most importantly, we output that information so that it can be used by somebody.

Now, if you want to pause the video here again and just update your description to match this one, it's really good because it takes in all those parts of the processes.

So, when we tried to categorise computers, in general, we have two different labels that we apply.

They can either be general purpose or embedded.

Now, a mobile phone and a coffee maker are both computers, but clearly they're very different.

So, let's have a go at doing this, before we've even talked about the characteristics, see if you can do it.

So, a mobile phone, would you say that as a general or embedded computer system? Five, point at the screen, four, three, two, have you got it? One.

It's a general purpose computer.

Now, mobile phones have lots of apps so they can do lots of different things, and those tasks are chosen by the user.

So, have a look at another one.

So, the coffee maker that we mentioned, is that a general purpose or embedded system? I'd like you to point at the screen again, I'm going to give you less time, so, three, two, have you got it? One.

This one's an embedded system.

Now, I did say that there were two options, so it might have seemed obvious, but the coffee maker is an example of an embedded system.

Let's see why that is.

General purpose computers, like my mobile phone, have a variety of uses and the tasks that can be to complete, it's usually chosen by the user.

My phone has tonnes of apps, but it can also make phone calls and send text messages.

And I decide what the phone does, that makes it a general purpose computer.

Embedded systems, on the other hand are much more specialised.

They do a limited number of things, but they do them really well.

My coffee maker, for example, has no apps, but it can make coffee much better than my mobile phone ever could.

And I, as the end user, can't really change what the coffee maker does.

I might be able to choose different settings, but I can't make it make phone calls without serious modifications to the computer.

So, this is the distinction between general purpose and embedded.

General purpose, lots of uses, chosen by the user.

Embedded systems, very specialised, limited number of uses, and the tasks are usually chosen by the manufacturer.

So, I've got another activity for you to do, now.

It's called spot the embedded systems. You've got a room here, that's full of computers.

And what I'd like you to do, is try and spot as many of them as you can, and then classify them as either general purpose or embedded.

So, remember, general purpose have a variety of uses, can be chosen by the user, and embedded systems and much more specialised, they can only do a limited number of things.

If you like to pause the video here, the room is on your worksheet.

So, you can use that to try and spot all the computers and then classify them.

Resume when you're done and we'll go through the answers.

Welcome back.

Did you find many? Should we have a look and see what ones are in there? Now, let's go through the general purpose computers first, 'cause there's slightly fewer of them.

The first one might have been obvious, but it's the mobile phone, that's on the sofa there.

We already spoke about this one and it's definitely general purpose.

Let's see if there are any others.

There's also a laptop.

Now, you might be watching this lesson on a laptop, but you could also use it to type a Word document, to edit videos, to do any number of things.

Definitely a general purpose computer.

There's also a tablet there on the table.

That's sort of similar to the mobile phone.

It might not be able to make phone calls, but it also has a variety of uses.

Still a general purpose computer.

One that you might not have spotted, or you might have thought was embedded is actually a games console.

A games console, especially modern ones, have a variety of uses.

You can literally do anything with them.

You can watch videos, you can play games, you can browse the internet, you can chat to your friends.

They have so many uses that really they are general purpose computers, now.

So, that's all the general purpose computers in there.

Now, let's have a look through the embedded systems and talk about each of them a little bit.

So, the first embedded system is, again, when we spoke about, there's a coffee maker here in the corner.

Again, very specialised.

It makes coffee really well, but it hasn't got any other uses ready, without taking it apart and modifying the insides.

There's also a vacuum robot, sometimes called a roomba.

These are little robots that walk around and vacuum your room.

Some of them are really clever in the way they mop out the room.

But that's another embedded system.

It's very specialised, it's great at doing that, but can't really do much else.

I've also got a thermostat over there.

So, that measures the temperature in the room, and might also tell your radiators turn on or off, depending on what the temperature is.

We've also got a security system.

This is one part of the security system.

And there might actually be other embedded systems around your house, all work together to create this security system.

This one looks like it's got a key pad.

So, probably where you put your passcode in to turn the alarm on or off.

We've then got a bunch of others.

And I won't bore you by going through them each one by one, but we've got a Bluetooth speaker, over there on the desk, that is very embedded, a printer, it's great at doing what it does, but it doesn't have a lot else to offer.

We have a smoke alarm, which is, might not think of it as a computer, but a lot of them are now, but they're also embedded, they can only do that thing.

And then a TV.

And this is a bit of a weird one, because smart TVs, I'd probably say are a bit more general purpose.

You might notice from these descriptions that, the line between general purpose and embedded is not a clear one.

There's no sort of, you're on this side, you definitely general purpose, You're on that side, you're definitely embedded.

It's sort of a grey area, and smart TVs live in that grey area, where they do have a variety of uses.

But most of those uses boil down to showing you stuff on the TV.

So, some key characteristics of general purpose computers, just to recap.

So, they're used for many different types of tasks and they have lots of resources.

And by resources, I don't mean sort of time or money, I mean computing resources.

Things like memory, storage capacity and the amount of CPU cores they have.

And most users will require a user.

If you'd like to pause the video here for a second, I would like you to have a go at writing in your notes, the key characteristics in embedded systems. Now, remember, these are the opposite of general purpose computers.

So, you should be able to use the key characteristics in general purpose as a guide.

So, you want to pause the video here, have a go writing those and then we'll have to go through.

Welcome back.

Should we have a look? So, embedded systems are specialised to a small number of tasks.

Now, the amount of tasks can vary depending on what the computer does, but in general, we're talking much more limited uses, the general purpose.

They also have limited resources and these are computing resources, again.

Most often it's just enough to accomplish what they need, and users are not always necessary.

So, for example, the smoke alarm doesn't need me there to tell it, to watch the smoke.

It just does its job and then will alert me if something happens.

Make sure, if you want to pause the video here again, just to make sure that your key characteristics match the ones I've got there, just in case you needed to make any edits.

If not, we can carry on.

Next, we going to have a look at the startup sequence.

Computers are a combination of the hardware components that make up the physical device and the software running on top.

We're going to ask ourselves a simple question to see how they work together.

What happens when you press the power button on your computer? Before we can get into this actual startup sequence, it's important that we're introduced to some of the key players.

You have met these components before, but we're going to go through them over the course of this unit.

I just want to give you an introduction so you know what we're talking about.

The first key player is the CPU.

This is a large chip inside your computer and it is the brains, it controls everything.

It does that process part of the computing cycle that we looked at earlier.

It also interacts with memory by loading things into, execute instructions and also saving things back, to either memory or secondary storage.

We also have RAM, which stands for Random Access Memory.

Now, RAM is both readable and writeable.

So, you can add, change or delete data, anytime.

It's also volatile.

Now, this is a special term that means when the power is turned off, all the data stored in RAM is lost.

It's also important to know there's extremely fast to read and write, much faster than say, a hard drive or a CD.

The other side of this is ROM.

ROM stands for Read-Only Memory.

Now, in a computer system, ROM is a small chip.

that's usually programmed by a manufacturer.

It's non-volatile, which means it keeps all the data, even if power isn't there, and it's also very fast to just like RAM.

Another piece of storage is the hard drive.

Now, this is called secondary storage and sometimes they're called the hard disc.

And it's the main storage device of your computer.

If you have files or folders or any other programmes, that probably stored on your hard drive.

The last, and probably most crucial player in this sequence is the BIOS, which stands for the Basic Input Output System.

This is stored on the ROM on your computer and it contains all the instructions needed for starting up the hardware on your computer.

When you startup and you press the power button, you might see a black screen that says, "Press F2 for Setup." That is the BIOS that you're looking at.

So, our challenge is to take the steps of this startup sequence, now, that you know the important players, and to put them in the right order.

On your worksheet, there are the steps labelled out for you.

So, you can either drag them, if you're doing it online or write them in, if you're doing it on the printed version.

If you want to pause the video here and then come back when you're done, we'll go through the right answers.

Welcome back.

How did you do? Should we have a look at what the right sequence is? So, you might have noticed that I already put the first and the last step in that for you.

So, the first step is that the boot sequence begins.

I put it in there for you because I think the word, begins, was a bit of a giveaway.

Let's have a look of what the next step is.

So, after the boot sequence begins, your CPU starts up and fetches the BIOS from ROM.

Is going to fetch it, And then the third step is it's going to store it in RAM.

So, this is an important thing that you need to remember is that, before anything can be executed, it first needs to be loaded into RAM.

So, the instructions from BIOS, so loaded into RAM, and then the BIOS starts up the monitoring keyboard.

This is the point in the startup where you see that black screen with the, "Press F2 for Setup." It starts a computer and the monitoring keyboard first, because it needs to make sure they can either show you some output or ask you to provide input, if anything goes wrong.

Next, the BIOS will check if the computer is working.

It'll do some basic checks to make sure there's RAM available, to make sure that it can access the secondary storage, and just do some general checkups, to make sure that all the hardware is expecting is there.

Then the Operating system is fetched from secondary storage.

So, your Operating system will be stored on a hard drive.

And first it needs to be fetched and then stored, you guessed it, in RAM.

Once it's loaded into RAM, the instructions are ready for the CPU to execute.

And so, the BIOS will hand over control to the Operating system.

This is when you get your login screen or your computer loads up.

So, that is the startup sequence.

Hopefully I showed you how the hardware and software on your computer interact to make the experience that you get.

Next activity is, we're going to talk about some systems software.

So, most computers require more than just a programme to run.

I can't just write something in Python, stick it onto a CPU, and then it runs.

There's another layer that's important for that to operate.

And this layer is called system software.

There are two key types of systems software.

There are Operating systems and utility software.

You see here that there's a top layer of software.

These are the things that we use every day.

Things like text editors, video players, web browsers, video games, or even the development environments with programming.

And the very bottom of this diagram, you can see if there's hardware.

These are the physical components that make up your computer, the CPU storage and memory, and the peripherals connected to it.

In between these two layers, we have system software, and its job is to facilitate the communication between those hardware components and the software above.

These are things that the user might not see, but that are necessary to keep your computer running.

And we're going to focus in on a particular piece of system software today called Operating systems. So, Operating systems are pieces of software that regulate interactions between software and hardware.

There are tonnes of different Operating systems, but the main ones are Windows, macOS, Linux, and Android.

Now, there's another task for you to complete on your worksheet.

If you'd like to pause the video here, I'd like you to say one Operating system is, based on what we've just covered.

And also given two examples of Operating systems, as well as the devices that they run on.

I'm going to pause the video here, resume when you're back, and we'll talk a little bit about the answers.

Welcome back.

So, hopefully you got, the Operating systems are pieces of system software that regulate interactions between hardware and software.

And also, you able to give two examples of Operating systems like Windows or Android, and some of the devices they run on.

Now, Operating systems have a bunch of different roles in the maintenance of your computer.

You can see the list here.

Now, instead of going through these one by one and me explaining what they are, I thought we will play a little bit of a game.

So, what I'm going to do is, I'm going to show you a description of one of these roles, as well as four options, and you're going to choose which role you think it is.

I'll then confirm it and then you can make notes on which one it is, ready? Let's start.

I've gotten rid of my camera for now, just so you can see the entire question, but let's get started.

So, the Operating system controls where each piece of data is stored in RAM.

Now, do you think that describes programme management, security, memory management or file handling? I'm going to give you five seconds for this.

I want you to point at the screen, which one you think it is? Five, four, three, two, one.

Hopefully you got it right, but it's memory management.

So, RAM is a form of memory and the Operating system manages where each piece of data is stored there.

If you want to pause the video and just make a note of memory management and the description above, we'll keep going.

Right, on to the next one.

So, instructions might be executed by the CPU, but the Operating system controls which instructions have fed in to be executed.

Now, do you think that's Input and Output, processor management, file management, or interaction with the user? Five, four, three, two, one.

That's right, that's processor management.

If you want to make a note of this, again, pause the video.

Process and management and the description above we'll keep going in a minute.

Right, welcome back.

So, the Operating system captures data from peripherals and provides data to the output to display to the user.

Now, I'm not going to read you all the options this time, but which one do you think it is out of these four? Five, four three, two, one.

Right, hopefully you got that, that one is Input, Output.

We're talking about Input and Output devices in the Operating system, captures the data, provides its programmes and also provides the data from the programmes for output devices to display.

Make a note of that one again, and we'll keep going.

I'm not going to give you as long for these ones, because that's obviously as we go, is less and less options.

So, hopefully you can see that there's one in here that we've already done, but let's have a look.

So, when you save data to your hard drive, the Operating system will find an available section of storage and send the data to be written to that location.

Which one of these four roles am I describing there? Three, two, one.

Great, hopefully you got that, that one was file management.

So, it manages where the files are stored on your hard drive.

If you'd like to pause the video again there, you can write down that description next to file management.

Alright, so, let's move on to the next one.

So, the Operating system will stop unauthorised individuals from accessing data on secondary storage or the data in memory.

Now, which one of the four options do you think is this time? I'm only going to give you three seconds.

So, you're ready.

Three, two, one.

Hopefully you got that it's security.

So, your Operating system will protect the data stored on your computer.

You can pause again here to make a note of that.

Next one.

When a programme fails or encounters a problem, the Operating system protects the wider system from crashing.

So, when your programmes run into a problem, your Operating system will protect the wider system.

Which one do you think that is? Three, two, one.

Correct, it's error handling.

So, when your programme runs into an error, which is what I almost said a minute ago, whoops, the Operating system will protect your wider system from crashing.

Stop that error causing a system crash.

Often our computers are running multiple processes at once.

The Operating system makes sure that each application has enough resources, again, these are computing resources, to accomplish its tasks.

Which one do you think it is? Three, two, one.

Perfect, this one is programme management.

So, even though it involves a processor, this is actually about the different programmes that are running.

And if you remember from earlier, we said that the Operating system handles which instructions will be executed by the CPU.

So, this is all part of that same process.

So, there's process and management and programme management, two sides of the same coin.

Pause here and make a note of that.

The Operating system also provides a graphical user interface, which makes operating the computer much simpler.

Which one do you think this is? Three, two, one.

Hopefully you got that one, yep, it's interaction with the user.

So, the icons you can see on your desktop, the file system, all that stuff is a graphical user interface the Operating system provides for you.

That's all for today's lesson.

Thank you so much for joining me for this first lesson of computer systems. I really hope you enjoyed it.

There's one thing I'd like you to do, and if you'd like to, you could please ask your parent or care to share your work on Instagram, Facebook, or Twitter, tagging @OakNational and using the hashtag, #LearnwithOak.

I'll see you next time.

Bye.