🎯 Learning Objectives
Develop the Hardware & Processing learning strand:
- Explore how the processor, main memory, and storage interact to execute programs in real scenarios.
- Define what an operating system is, and provide an overview of what it does.
💬 Key Vocabulary
- Program
- instructions
- data
- hardware
- processor
- memory
- storage
- communication
- input and output
- operating system
📝 Starter Activity – Forbidden Words
In a sentence, describe the word at the top of each card, without using the forbidden words below it.
Example: “It’s the component that manages what is shown on your monitor.”
How to play:
The first player in the pair should press next on the slideshow below while the other looks away.
Write down your description on a blank word document then read your description out and see if the other person can guess it. Then swap back and forth until you have done three each.
📖 RECAP: Hardware components
The processor is the component that executes program instructions.
An instruction may:
- Perform arithmetic or logic operations on data
- Perform input/output of data
- Control program flow
The main memory is the component that stores the programs and data currently in use.
Main memory is volatile: its contents are lost when the power is off.
The storage (secondary memory) is the set of components that stores programs and data.
Storage is persistent: it retains its contents when the power is off.
📖 A scenario
Stella is fascinated with the sky. She takes photos of it during the day and studies it with a telescope at night.
Scenario: Stella uses planetarium software to identify the objects that she observes in the night sky.
We will examine what happens behind the scenes as she uses the software.
Stella starts the planetarium software.
Behind the scenes
The program is copied from storage into the main memory (RAM).
Behind the scenes
Celestial object data (e.g. names and positions) is copied from storage into the main memory (RAM).
Behind the scenes
Program instructions are fetched one by one from the main memory into the processor, along with the celestial object data that they will operate on.
Behind the scenes
Each instruction, executed by the processor, performs an operation on the celestial object data, to compute the simulated view of the night sky.
Behind the scenes
Any data resulting from the execution of an instruction is transferred back from the processor into the main memory.
📝 Activity 1 – Scenarios
Examine similar scenarios to that above, using your worksheet by downloading it using the button below.
📖 How many programs at once?
Question: How many programs can be executed at the same time?
Answer
Answer: Just one!
At any given time, the processor executes one instruction✻ that is part of one program.
Executing multiple programs
The processor can be made to alternate between executing the instructions of different programs.
This creates the impression of simultaneous program execution.
✻ Modern processors have multiple cores.
Each core can execute instructions from a different program. In the building analogy, this is like having multiple workers.
This speeds things up considerably, but alternation between programs is still necessary.
Watch an animation of a wall building analogy:
A (single-core) processor can execute one instruction at a time. However, computers create the illusion of executing multiple programs simultaneously by alternating very fast between executing the instructions of each individual program.
This program is a simulation that explains this idea by using an analogy: a single builder can work on one wall at a time. However, the builder can create the illusion of working on all four walls simultaneously by alternating very fast between working on each individual wall.
Select a low speed to see how the builder works on one wall at a time and alternates and then increase the speed to see how the four walls seem to be progressing simultaneously.
The trowel at the bottom indicates the wall that the builder is currently working on.
📖 More questions
What determines how the processor time is allocated?
What determines where the programs and data are stored in the main memory?
What determines how the programs and data are organised in storage?
Answer
The operating system.
📖 The operating system
The operating system is a set of programs that controls the operation* of a computing system.
- *Program execution
- *Memory management
- *File system organisation
- *Input and output
- *Communication
- *Graphical user interface
Question: Had you heard of the operating system before? Did you have an idea of how important it is?
Question: Can you name some examples of operating systems?
Tip: The operating system is the first program that a computing system starts executing, as soon as it powers up.
Answer
📝 Activity 4 – System Monitor
Software that monitors our computing system can help us visualise some of its complexity.
We can see measurements for:
- Processor load
- Main memory usage
- Network activity
Watch the screen recordings of a user performing different tasks below.
Use your worksheet to record readings of the system monitoring software and answer questions.
Task 1 – Idle
Task 2 – Planetarium
Task 3 – Image editing
Task 4 – Streaming
Explorer Task – Browsing
📝 Plenary – Power Up
Think, write, pair, share .
Can you describe what happens when you power up your computer?
Tip: The operating system is the first program that a computing system starts executing, as soon as it powers up.
In this lesson, you…
- Explored how the processor, main memory, and storage interact to execute programs in real scenarios
- Defined what an operating system is, and provided an overview of what it does
Next lesson, you will…
- Describe three logical operators, and how they are used to form logical expressions
- Use logic gates to construct logic circuits, and associate these with logical operators and expressions
- Describe how hardware is built out of increasingly complex logic circuits
🏅 Badge it
🥈 Silver Badge
- Complete the Starter Activity – Forbidden Words and upload the Word document to www.bournetolearn.com.
🥇 Gold Badge
- Complete Activity 1 – Scenarios and upload the Word document to www.bournetolearn.com.
🥉 Platinum Badge
- Complete Activity 4 – System Monitor and upload the Word document to www.bournetolearn.com.