Lesson video

Hello, my name is Mrs. Holborow, and welcome to computing.

I'm so pleased you've decided to join me for today's lesson.

In this lesson, we are going to be looking at the features and role of assembly language in computing.

Welcome to today's lesson from the unit: Programming Sequence.

This lesson is called Assembly Language, and by the end of today's lesson, you'll be able to describe the purpose of assembly language and how it interacts with computer hardware.

Shall we make a start? We will be exploring these keywords in today's lesson: Assembly language.

Assembly language: a language that replaces machine code with short, readable instructions to make it easier for humans to write and understand the language.

Machine code.

Machine code: a programme written using 1s and 0s that a computer can execute directly.

Look out for these key words throughout today's lesson.

Today's lesson is broken down into two parts.

We'll start by identifying features of assembly language.

We'll then move on to explain the role of assembly language in computing.

Let's make a start by identifying features of assembly language.

The first ever programmes were written solely in machine code where each instruction was entered by hand before being executed.

This process was very time-consuming.

Here's some example of some machine code and what the numbers represent.

Assembly language was introduced as a more efficient way for programmers to write machine code.

Instead of using raw binary, assembly language uses a set of mnemonics, which are short, human-readable representations of the opcodes.

For example, instead of writing binary codes like 0001, you would use a mnemonic like ADD to represent that operation.

Time to check your understanding.

What is the main characteristic of machine code? Is it A, it uses human-readable words for instructions? B, instructions are entered as binary code, 1s and 0s.

Or C, it is easy to read and write.

Pause the video whilst you have a think.

That's right.

In machine code, instructions are entered as binary code or 1s and 0s.

Here's some more examples of some operations in machine code compared to their assembly language equivalent.

So we have 0001, which in assembly language is represented by ADD or A-D-D.

This adds a number to the current value stored in the computer's temporary working space.

0101 is represented in assembly language by LDA.

This takes a number from a specific place in the computer's memory and puts it into the working space.

0110 is represented in assembly language by BRA.

This skips ahead or goes back to a different part of the programme to continue instructions from there.

This was great for programmers, but the computers still couldn't understand the instructions.

To solve this, assemblers were created to automatically translate the assembly language into machine code.

Both assembly language and machine code are low-level languages.

Each line of assembly language corresponds to one line of machine code.

The machine code is specific for the CPU that it is written for.

So here, we've got some examples.

On the top, we have some assembly language, and then underneath, we have some machine code written in binary 0s and 1s.

There is a one-to-one relationship between assembly language and machine code.

This means that each assembly instruction translates into one machine code instruction.

This is an example comparing Python, assembly language, and machine code.

So you can see in Python, the instruction is written in one line.

Sum is equal to 5 + 2.

In assembly language, that's represented as LDA 5 ADD 2 STA result.

And then we have the machine code representation.

Notice that the assembly language and machine code are each represented as three separate lines.

Python is an example of a high-level language.

Assembly language and machine language are both low-level languages.

Time to check your understanding.

What is the purpose of an assembler? Is it A, to translate assembly language into machine code? B, to translate machine code into assembly language.

Or C, to translate high level languages like Python into assembly language.

Pause the video whilst you have a think.

That's right.

The correct answer is A.

An assembler translates assembly language into machine code.

Okay, we're moving on to our first task of today's lesson, and you're doing a fantastic job so far, so well done.

I'd like you to describe three key features of assembly language and explain how it relates to machine code.

Pause the video whilst you complete the activity.

How did you get on? Let's have a look at a sample answer together.

Assembly language uses short codes to represent machine code instructions.

Each assembly instruction matches one machine code instruction.

It is a low-level language that allows direct control over hardware.

And the instructions are converted using an assembler.

Remember, if you want to revisit your answer and add any detail, you can pause the video now.

Okay, we're moving on to the second part of today's lesson now.

We're going to explain the role of assembly language in computing.

Assembly language serves as a bridge between human-readable programming languages and the binary machine code that the computer's CPU can understand.

High-level languages, like Python, allow programmers to write code using simpler instructions.

Assembly language offers greater control over the hardware by translating specific operations into machine code.

Many older computer systems and software, known as legacy systems, were originally written in assembly language.

These systems are still in use today, and understanding assembly language is important for maintaining them and ensuring they continue to run effectively.

For example, NASA's Voyager probes, which have been in space since the 1970s, still rely on assembly-based software.

Engineers need knowledge of assembly language to keep these spacecraft operational.

Time to check your understanding.

What is a key advantage of using assembly language over high-level languages? Is it A, it allows programmers to write their code using simpler instructions? B, it offers greater control over the hardware.

Or C, it is more portable across different computer systems. Pause the video whilst you have a think.

That's right.

The correct answer was B.

It offers a greater control over the hardware.

Well done.

Assembly language is particularly important in situations where efficiency and performance are critical.

It allows programmers to optimise code for memory usage and processing speed.

Assembly language is commonly used in embedded systems. These are small, dedicated systems designed for specific tasks.

Some examples include smart watches, fitness trackers, robotics, medical devices, and car engine control systems. Embedded systems are designed to perform specific tasks efficiently and are often restricted in size, making high-level programming impractical.

Low-level languages allow programmers to create programmes that make the best use of limited processing power and memory.

This efficiency is crucial in embedded systems. Low-level languages offer precise control over hardware and are ideal for writing device drivers.

Device drivers enable a computer to communicate with peripherals like a mouse or a printer.

It provides fast and efficient data transfer and command execution.

Time to check your understanding.

Why are low-level languages particularly important in embedded systems? Is it A, because embedded systems have unlimited processing power and memory? B, embedded systems are designed to specific tasks efficiently and often have limited resources.

Or C, embedded systems do not require programming.

Pause the video whilst you have a think.

Did you select B? Great work! Embedded systems are designed to perform specific tasks efficiently and often have limited resources.

Okay, we are moving on to our final task of today's lesson.

Task B: Describe the role of assembly language in computing, including why it remains important for certain types of systems, and give two examples in your answer.

Pause the video whilst you have a go at the activity.

For part two, a basic robot vacuum cleaner has 32 megabytes of RAM compared to 4 gigabytes in a typical new laptop.

Explain why programming of the robot is likely to be done using assembly language rather than a high-level programming language.

Pause the video whilst you complete the activity.

How did you get on? Let's have a look at some sample answers together.

So for part one, you were asked to describe the role of assembly language in computing, including why it remains important for certain types of systems, and you were asked to give two examples.

Assembly language bridges the gap between human-readable code and machine code, giving programmers greater hardware control.

It remains important for maintaining legacy systems like older spacecraft and for programming embedded systems, device drivers, and real-time systems where efficiency is crucial.

If you need to pause the video and add any detail to your answer, you can do that now.

For part two, a basic robot vacuum cleaner has 32 megabytes of RAM compared to 4 gigabytes in a typical new laptop.

Explain why programming of the robot is likely to be done using assembly language rather than a high-level programming language.

The memory available for a robotic vacuum cleaner is a lot lower than a typical computer such as a laptop.

By using assembly language, the designers of the robot can make sure that the programme controlling its operation is as small as possible.

This means that the overall amount of memory can be kept low, reducing the cost of the product while still ensuring the robot has sufficient memory to operate effectively.

Okay, we've come to the end of today's lesson and you've done a great job, so well done.

Let's summarise what we have learned in this lesson.

Assembly language is a low-level programming language, meaning that it's closer to the computer's language than a high-level language like Python.

It provides direct control over the computer's hardware, allowing you to manipulate components like registers and memory locations.

Assembly language is used for critical applications and embedded systems, where maximum efficiency and precise control are necessary, often resulting in machine code.

I hope you've enjoyed today's lesson and I hope you'll join me again soon.

Bye.