Lesson video

Hi, my name's Mr. Hall, and welcome to this Oak National Academy lesson, which is called traditional computer systems, and is taken from the unit computer systems and data science.

Thank you very much for joining me for this lesson today.

I look forward to learning with you today and in future lessons.

So let's get started.

The outcome of today's lesson is that you'll be able to describe how general-purpose computers use programmes to perform a wide range of tasks.

In this lesson, we have two keywords.

The first keyword is computer.

So a computer is an electronic device that processes data and performs tasks.

And the second key word is programme.

And a programme is a set of instructions that tells a computer what to do.

So there's our two key words, computer and programme.

And we have two learning cycles in this lesson as well.

So the first learning cycle is that you will describe computer programmes, and then later in the lesson, you'll move on to explain general-purpose and single-purpose computers.

So let's get started with that first learning outline of describing computer programmes.

So here's Laura, and she says, "Wow! That machine looks cool, it must be really old.

What is it?" So what do you think it is? So Andeep says, "You're right Laura, it is really old." And the machine is called Babbage's analytical engine.

So let's find out a little bit more about that machine.

The analytical engine was a proposed mechanical general-purpose computer designed by Charles Babbage in the 1830s.

And here you've got a picture of the analytical engine and if you want to see this in real life, it's on display in the science museum in London.

So let's find out a little bit more about Charles Babbage himself.

So he lived from 1791 to 1871, and he was an English mathematician, philosopher, inventor, and mechanical engineer.

So he was an all round, clever chap.

Babbage's ideas were far ahead of his time.

Actual computers wouldn't be built until over a century later, so he really was working ahead of his time.

His work laid the foundations for modern computing principles that we know today.

And we'll look at some of those principles in this lesson and in this unit.

So let's have a little think about what a computer actually is.

So a nice definition of a computer is that it's a device that's designed to process data and perform useful tasks.

So Babbage's analytical engine was a mechanical computer that used a variety of gears, cams, and other physical elements to do its work.

So the machine operated without electricity.

So it's very, very different to modern computers that you would see today.

And you might not be able to get an idea of the scale of the machine from these pictures, but it was big, so far bigger than modern computers today.

And the way it used variety of gears, and cams, and physical elements probably had more in common with a mechanical engine that you might see in something like a car than a computer.

But as you can see, it was a highly complex machine with lots of different moving parts.

So Babbage's analytical engine was designed to be programmable and could, in theory, perform any calculation or algorithm.

Sadly, the analytical engine was never fully built in Babbage's lifetime due to financial and technical limitations.

And that was partly 'cause he was really pushing the boundaries of the technology at that time.

However, it's still considered to be one of the earliest concepts of a modern computer.

And after his death, people worked to complete the machine so that there is now a fully working version of the machine in the science museum.

So let's look at someone else who was instrumental in the development of computing.

So this is Ada Lovelace who lived from 1815 to 1852, and she was a mathematician who worked with Babbage.

She's credited with writing the first algorithm intended to be processed by the analytical engine.

So this earned her recognition as the first person to write a computer programme way back in the 19th century.

So we can now describe computer programmes.

A computer programme is a set of instructions that tells a computer what to do.

Without a programme, a computer would have no instructions to execute and will be unable to complete any tasks.

A computer without a programme is a bit like a car with no driver.

It has all the parts to move, but no direction.

The programmes written for the analytical engine were stored on things called punch cards.

You can see a picture of some punch cards on the right of the screen here.

So a punch card is an early form of data storage and input for computers and mechanical devices, and they're simply small cards with holes punched in them in different places.

Punch cards were a useful way to programme a machine before keyboards or modern storage existed.

Time for a question.

Who is widely credited with writing the first computer programme? Is it A, Charles Babbage? Is it B, Alan Turing? Or C, Ada Lovelace? That's right.

Ada Lovelace wrote the first computer programme and she wrote it to run on the machine, which was invented by Charles Babbage.

Another question, which of these was an early form of data storage used within the analytic engine? Was it A, punch cards, B, floppy disc drive, or C, a flash drive? That's right.

So punch cards were used as an early form of data storage within the analytical engine.

So Jun, having looked at that, he's made an observation.

He says, "I don't think my computer uses punch cards, so how is my computer programmed?" And the answer is that modern computers are programmed using digital software written in programming languages such as Python, Java, or C, and there's several more languages as well.

So modern programmes are programmed using any one of these or other languages.

Once written, the instructions in the programme can be executed on a computer.

A good programme gives the computer clear, complete, and correct instructions to perform a specific task.

Programmes are needed to perform every task on a computer.

You've probably used many computer programmes already today.

Can you think of any examples where you may have used a computer programme today? So Laura's come up with an example.

She used a word processor programme to type up her English essay.

So the programme on the computer was a word processor and she used it to type up an English essay.

A word processor programme tells the computer how to respond to your typing, show text on the screen, and save your work.

So when you use the keyboard and hit the keys on the keyboard, those letters are represented in the programme as you're writing.

Andeep has an example.

He says, "I used a web browser programme on my laptop to search for information for my history homework." And in this case, the web browser programme tells the computer how to turn your typing into a request, get the information from the internet, and show it to you on your screen.

So a web browser programme does a lot of things for you.

Sam's come up with an example as well, who says, "I'm creating a song using a music programme on my mobile phone." And these kind of programmes let you record sounds and beats and mix different tracks to make music.

So really, really creative pieces of software.

Jun said, "I used a video streaming service on my TV this morning.

That's a computer programme too." So these streaming services, they have programmes which allow you to watch shows and movies by connecting to the internet and playing videos on demand.

So you can watch whatever you want whenever you want to.

Computer programmes range in size from just a few bytes to many gigabytes or even terabytes.

The size of them all depend on the complexity of the tasks that the computer needs to perform, from really simple tasks to very complex tasks.

More complex tasks require more instructions in the programme, which means the code becomes longer and more detailed.

Small programmes that do simple tasks such as controller timer might only need a few lines of code and a single programmer.

Large programmes such as video games and streaming platforms can have millions of lines of code.

They're much more complex than these simple examples we've seen up until now.

They may be developed by hundreds of programmers at any one time.

Sam has a question.

"What about media files such as photos, videos, and music? Are they programmes?" And Laura says, "No, I don't think so, Sam.

They don't give a computer any instructions." And Laura's absolutely correct.

Media files are not programmes.

They are the content that programmes open, display, or play.

So there's a big difference between a programme and a media file such as a photo, a video, or some music.

Remember that computers are just machines, they don't think or act without a programme.

Computer programmes, whether large or small, are sets of instructions that tell a computer what to do.

Without a programme, the computer cannot perform any tasks on its own.

So let's have a look at a true or false question.

Media files such as videos, images, and music are all programmes.

Is that true or false? Well done, that's false.

Can you explain why? So well done for remembering media files are not programmes.

They are the content that programmes open, display, or play.

Another true or false question, programmes are needed to perform every task on a computer.

Is that true or false? Well done, that's true.

So programmes are needed to perform every task on a computer.

Now, time for your task.

First, in your own words, write a few sentences to describe what a computer programme is, then write two or three sentences about two different computer programmes.

Okay, let's have a look at what you could have written.

So in your own words, write a few sentences to describe what a computer programme is.

A computer programme is a set of instructions that tells a computer what to do.

Without a programme a computer would have no instructions to execute and will be unable to complete any task.

Computer programmes range in size from very small for things like timers to very large for things like video games and web browsers.

And the second part of your task, write two or three sentences about two different computer programmes.

So you could have written about a web browser, which is a computer programme that lets users access and view websites on the internet.

A computer follows the instructions in the programme to load pages, display text, and images, and play videos.

And a word processor is a programme used to create and edit text documents, it allows users to type, format, and save their writing, making it useful for essays, reports, and letters.

The programme gives the computer all the instructions it needs to perform these tasks.

Now we can move on to our second learning cycle, which is to explain general-purpose and single-purpose computers.

So Laura says, "Andeep, did you know that all computers are not the same?" And Andeep says, "What do you mean, Laura?" So let's find out.

So Laura adds, "Some computers are designed to do just one job like controller device which heats your food." Such as a microwave.

"Whereas others are built to do many different tasks like writing documents, playing games, or browsing the internet." And here's an example of a laptop computer which can do all those things.

And Andeep says, "Oh, that makes sense!" Computers can be either general-purpose or single-purpose.

Single-purpose computers are built to complete just one task.

General-purpose computers are built to perform many different tasks.

General-purpose and single-purpose computers execute the instructions contained in programmes to do their work.

So they have that in common.

They both use programmes.

The computer hardware and software programmes work together as a system to perform tasks.

And again, single-purpose and general-purpose computers have that in common.

A single-purpose computer usually runs only one programme, whereas a general-purpose computer can use many different programmes to complete a wide variety of tasks.

Time for a true or false question.

A single-purpose computer usually runs a single programme.

Is that true or false? A single-purpose computer is designed to do just one job.

So it usually runs only one programme.

For example, a washing machine or a digital thermometer has one programme that controls all of its functions.

Single-purpose computers are often built into devices that we use every day.

You might find single-purpose computers in things like microwaves, washing machines, or calculators.

In a microwave, a single-purpose computer executes a programme that controls the cooking time and the heating of food.

In a washing machine, a single-purpose computer executes a programme to control the wash cycles.

And in a calculator, a single-purpose computer executes a programme that enables it to perform basic maths functions.

Note that single-purpose computers cannot multitask or switch between different programmes.

So they can't do that.

This makes them simple and efficient at their job, but not flexible as they're limited to the one task they were designed and built for.

Although single-purpose computers vary, they usually have key features such as: only executing one programme, they cannot be used for other tasks, they're simple, reliable, and efficient for their purpose.

A general-purpose computer can be used to complete many different tasks.

Laptops, desktops, smartphones, and tablets are all examples of general-purpose computers.

This is because you can instal and execute different programmes to get them to do different tasks.

Through each different programme, a general-purpose computer transforms itself into a machine to perform different tasks.

You can execute programmes such as web browsers, word processors, or video games.

General-purpose computers can run all these different types of programmes.

If you want to browse the web to find information, you can get the computer to execute a web browser programme.

In fact, you could choose to use a number of different web browser programmes if you wanted.

So you'd have a choice.

There are many different web browsers you could choose from.

If you wanted to write an essay using the information you found in a web browser, you could switch your computer to a word processor programme to start typing it up.

You could even keep the web browser and the word processor programmes running at the same time if you want to have both workspaces open at once.

If you wanted to play a video game after finishing your essay, you could have the computer execute a video game programme.

You could get the computer to swap games programmes and play many different titles.

So after hearing all about this, Andeep has question.

"How do general-purpose computers use programmes?" When you open a programme such as a web browser, the computer loads it into memory.

The central processing unit, or the CPU, follows the steps in the programme to process data, make decisions, and show results.

On general-purpose computers, it's possible to download, instal, and execute many different programmes.

This is why they are flexible and can be used to complete so many different tasks.

Note that general-purpose computers need to have a full operating system to work.

And there's an obvious question from Andeep on that.

"So what is an operating system?" An operating system, or OS, is the main programme that manages the computer's hardware and allows other programmes to run.

The table below compares the features of general-purpose and single-purpose computers.

So first of all, the feature, so the main use for a general-purpose computer is that it can do many different tasks, whereas a single purpose computer is designed for one specific task.

Examples of general-purpose computers are laptops, smartphones, tablets, and examples of devices with single purpose computers in them are calculators, microwaves, or washing machines.

Can they run multiple programmes? So a general purpose computer, yes, it can run many types of multiple programmes, whereas a single purpose computer, no, just runs the built-in software.

And do they have an operating system? So a general purpose computer, yes, does have an operating system, whereas a single purpose computer does not because it doesn't have anything it needs to manage, so it's only running one programme or application.

Time for a question.

Which of these devices is controlled by a single-purpose computer? Is it a laptop PC, a desktop PC, or a microwave oven? Well done, it's a microwave oven.

So a microwave oven will often contain a single -purpose computer to control the heating of the food and the timer.

And next question, which of these is an example of a general-purpose computer? Is it a calculator, a tablet PC, or a washing machine controller? Well done, it's a tablet PC.

So a tablet PC has an operating system and runs multiple programmes at the same time.

So that's a general-purpose computer.

Now a true or false question.

General-purpose computers are built to perform a single task.

Is that true or false? Well done, that's false.

Can you explain why? Absolutely right.

General-purpose computers are built to perform many different tasks.

So now time for a task.

So fill in the blanks in this statement.

So the statement is, a blank gives the blank that computers need to perform tasks like processing data, such as numbers, text or images.

Blank purpose computers are built and programmed to do just one job.

Blank purpose blank can run many different programmes to complete different tasks.

And the words you have to fill in are general, instructions, single, computers, and programme.

So let's read that sentence as it should be.

So a programme gives the instructions that computers need to perform tasks like processing data, such as numbers, text, or images.

Single-purpose computers are built and programmed to do just one job.

General-purpose computers can run many different programmes to complete different tasks.

Second part of your task.

In your own words, explain how general-purpose computers use programmes to perform a wide range of tasks.

So you could have written something like this.

General-purpose computers are designed to be flexible and can complete a wide range of tasks.

They run many different programmes.

Each programme is made of instructions that tell the computer what to do to perform the different tasks.

If you wanted to perform a specific task like writing a document, you can open a word processor programme and that computer executes the instructions within it.

If you wanted to swap tasks and play a video game, you could just open that programme.

So let's have a look at a summary of this lesson which was called traditional computer systems. Computers need programmes to perform tasks.

A programme gives the instructions that computers need to perform tasks like processing data such as numbers, text, or images.

Single-purpose computers are built and programmed to do just one job.

General-purpose computers can run different programmes to complete different tasks.

Thank you for joining me for this Oak National Academy lesson today.

I look forward to seeing you again for more lessons in the future.