Save a copy Lesson 3 Orchestra conductor Year

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Save a copy Lesson 3: Orchestra conductor Year 8 – Computing systems

Save a copy Lesson 3: Orchestra conductor Year 8 – Computing systems

Starter activity Forbidden words In a sentence, describe the word at the top of

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. ” Process: Six cards for each pair, face down. Draw three cards, write your descriptions, then let your partner write down their guesses. Describe this word to your partner. You are not allowed to use these words. Graphics processor Screen Display Colours Resolution GPU

Starter activity Hardware components The processor is the component that executes program instructions. An

Starter activity 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 Processor Execute Process Program Data CPU Think of these as keywords

Starter activity Hardware components The main memory is the component that stores the programs

Starter activity Hardware components 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. Memory Store Program Data Volatile RAM Think of these as keywords

Starter activity Hardware components The storage (secondary memory) is the set of components that

Starter activity Hardware components 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. Storage devices Store Program Data Persistent Hard disk Think of these as keywords

Objectives Lesson 3: Orchestra conductor In this lesson, you will: ● Explore how the

Objectives Lesson 3: Orchestra conductor In this lesson, you will: ● 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

Activity 1 A scenario Stella is fascinated with the sky. She takes photos of

Activity 1 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. screenshot of Stellarium, an example of the software that Stella could be using

Activity 1 A scenario Stella starts the planetarium software. processor Behind the scenes The

Activity 1 A scenario Stella starts the planetarium software. processor Behind the scenes The program is copied from storage into the main memory (RAM). memory storage

Activity 1 A scenario Stella starts the planetarium software. processor Behind the scenes Celestial

Activity 1 A scenario Stella starts the planetarium software. processor Behind the scenes Celestial object data (e. g. names and positions) is copied from storage into the main memory (RAM). memory storage

Activity 1 A scenario Stella starts the planetarium software. processor Behind the scenes Program

Activity 1 A scenario Stella starts the planetarium software. processor 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. memory storage

Activity 1 A scenario Stella starts the planetarium software. processor Behind the scenes Each

Activity 1 A scenario Stella starts the planetarium software. processor 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. memory storage

Activity 1 A scenario Stella starts the planetarium software. processor Behind the scenes Any

Activity 1 A scenario Stella starts the planetarium software. processor Behind the scenes Any data resulting from the execution of an instruction is transferred back from the processor into the main memory storage

Activity 1 Scenarios Examine similar scenarios, using your worksheet.

Activity 1 Scenarios Examine similar scenarios, using your worksheet.

Activity 2 How many programs at once? Question How many programs can be executed

Activity 2 How many programs at once? Question How many programs can be executed at the same time? Answer Just one! At any given time, the processor executes one instruction✻ that is part of one program. Then how can this be explained?

Activity 2 How many programs at once? Question How many programs can be executed

Activity 2 How many programs at once? Question How many programs can be executed at the same time? 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. Watch an animation of a wall building analogy: ncce. io/wall-building

Activity 2 How many programs at once? Question How many programs can be executed

Activity 2 How many programs at once? Question How many programs can be executed at the same time? Answer Just one! At any given time, the processor executes one instruction✻ that is part of one program. ✻ 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.

Activity 3 More questions What determines how the processor time is allocated? What determines

Activity 3 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? processor memory storage

Activity 3 More questions, same answer What determines how the processor time is allocated?

Activity 3 More questions, same answer 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.

Activity 3 The operating system is a set of programs that controls the operation✻

Activity 3 The operating system is a set of programs that controls the operation✻ of a computing system. In some ways, the operating system is like the conductor of an orchestra.

Activity 3 The operating system is a set of programs that controls the operation✻

Activity 3 The operating system is a set of programs that controls the operation✻ of a computing system. Question Had you heard of the operating system before? Did you have an idea of how important it is? ✻ Program execution Memory management File system organisation Input and output Communication Graphical user interface This is how your system looks; it’s the only aspect of the OS you really get to see. However, it’s only the tip of the iceberg.

Activity 3 The operating system: examples The operating system is a set of programs

Activity 3 The operating system: examples The operating system is a set of programs that controls the operation✻ of a computing system. 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.

Activity 3 The operating system: examples by Microsoft Corporation by Apple Inc. a Linux

Activity 3 The operating system: examples by Microsoft Corporation by Apple Inc. a Linux distribution Android™ i. OS Raspberry Pi OS based on Linux by Apple Inc. based on Debian Linux used on Raspberry Pi computers by the Open Handset Alliance by Canonical

Activity 4 Monitoring the system Software that monitors our computing system can help us

Activity 4 Monitoring the system 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 Demonstration: ncce. io/vid-idle

Activity 4 Monitoring the system Watch screen recordings of a user performing different tasks.

Activity 4 Monitoring the system Watch screen recordings of a user performing different tasks. Use your worksheet to record readings of the system monitoring software and answer questions.

Activity 4 Monitoring the system: idle This is what system resources look like after

Activity 4 Monitoring the system: idle This is what system resources look like after the system has powered up. Notes The processor is only busy 10% of the time, mainly executing the operating system. The main memory is mostly occupied by the operating system. There is almost no communication over the network.

Activity 4 Monitoring the system: planetarium Planetarium software is used to simulate the night

Activity 4 Monitoring the system: planetarium Planetarium software is used to simulate the night sky. 1 The program starts. 2 The user interacts with the program. 3 The program is terminated. 1 2 3

Activity 4 Monitoring the system: planetarium Planetarium software is used to simulate the night

Activity 4 Monitoring the system: planetarium Planetarium software is used to simulate the night sky. Notes Upon startup, the program and its data are loaded into the main memory. Computation is required throughout to simulate views of the night sky. Upon termination, processor load drops and memory resources are released. Some network activity is observable at startup (checking for updates? ). 1 2 3

Activity 4 Monitoring the system: image editing Image editing software is used to rotate

Activity 4 Monitoring the system: image editing Image editing software is used to rotate a large image. 1 The program starts. 2 The image is loaded. 3 The rotation of the image starts. 4 The program is terminated. 1 2 3

Activity 4 Monitoring the system: image editing Image editing software is used to rotate

Activity 4 Monitoring the system: image editing Image editing software is used to rotate a large image. Notes When loaded, the image occupies a significant amount of the main memory. The rotation operation requires intensive computation on a large image. Memory usage increases as the rotation progresses (storing the result of the operation, i. e. the rotated image). Network communication is insignificant. 1 2 3

Activity 4 Monitoring the system: video streaming A browser is used to play an

Activity 4 Monitoring the system: video streaming A browser is used to play an online video. 1 The browser starts. 2 The website with the video is retrieved. 3 The video starts playing. 4 The browser is terminated. 1 2 3 4

Activity 4 Monitoring the system: video streaming A browser is used to watch an

Activity 4 Monitoring the system: video streaming A browser is used to watch an online video. Notes There is increased computation when the program starts, the web page is rendered, and the video is played. Memory usage also increases at these points. There is a substantial amount of communication over the network. 1 2 3 4

Activity 4 Monitoring the system: browsing A browser is used to visit a website

Activity 4 Monitoring the system: browsing A browser is used to visit a website and download a large image. 1 The browser starts. 2 The website is retrieved. 3 The large image is retrieved. 4 The browser is terminated. 1 2 3 4

Activity 4 Monitoring the system: browsing A browser is used to visit a website

Activity 4 Monitoring the system: browsing A browser is used to visit a website and download a large image. Notes Computation is intensive when the program starts and the website is rendered. The website does not require much communication over the network. Communication is intensive while the image is retrieved. 1 2 3 4

Plenary A scenario: power up Think, write, pair, share. Can you describe what happens

Plenary A scenario: 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.

Summary In this lesson, you. . . Next lesson, you will. . . Explored

Summary In this lesson, you. . . Next lesson, you will. . . Explored how the processor, main memory, and storage interact to execute programs in real scenarios Describe three logical operators, and how they are used to form logical expressions Defined what an operating system is, and provided an overview of what it does 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