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1 – Get in Gear

In this unit, you will…

Investigate different layers of computing systems:

  • From programs and the operating system
  • To the physical components that function together as a system to execute these programs
  • To the fundamental binary building blocks that these components consist of

In this lesson, you will…

  • Learn what the purpose of a computing system really is
  • Explore what programs are, and look at specific examples of programs that we often use

🎯 Learning Objectives

  • Recall that a general-purpose computing system is a device for executing programs
  • Recall that a program is a sequence of instructions that specify operations that are to be performed on data
  • Explain the difference between a general-purpose computing system and a purpose-built device

💬 Key Vocabulary

  • Computer
  • software
  • device
  • program
  • instructions
  • system

🥇 Level 1 – The Antikythera mechanism

It was retrieved in 1900 from a Roman shipwreck off the coast of Antikythera island.

It was constructed some time in the 1st or 2nd century BC.

We now know that it was a complex geared mechanism that could predict solar eclipses, as well as the position of the moon and known planets.

 Think, write, pair, share

  • Would you call the Antikythera mechanism a computer?
  • How is it similar or different to modern computers?

Download and write your answers to these questions in this worksheet.

Use the worksheet below to write down some of the programs you know.

Download Level 1 Activity

📖 The Pascaline and the stepped reckoner

Pascal (1642) and Leibniz (1672) designed calculating machines.

Leibniz’s machine was the first to add, subtract, multiply, and divide.

 Question

  • How are these machines similar or different to modern computers?

Automate the process

Question

  • What is Leibniz suggesting here?

“If we wanted to produce a more admirable machine it could be so arranged that it would not be necessary for the human hand to move the machine from operation to operation: Things could be arranged in the beginning so that everything should be done by the machine itself.”

Extract from Leibniz’s description of the Machina arithmetica

Babbage’s Analytical Engine

Babbage (1837) conceived of a programmable machine that would perform calculations, as specified by instructions on punched cards. 

Question

  • How is this machine similar or different to modern computers?

Calculating machines

  • Purpose-built: designed to automate a specific process.
  • The data and operations to be performed are either specified manually by the user, or hardwired into the machine.

Modern computers

  • Receive input,  process it, produce output.
  • General-purpose: designed to automate any process, as specified by a program.
  • The data and instructions to be performed can be stored in memory.

This will be our definition of a computer.

📖 What makes a computer different…

…than an appliance such as a dishwasher?

The computer is the only appliance that can do more than one thing. Toasters toast. Refrigerators cool. Lamps illuminate.

One appliance, one task.

But the computer can do hundreds of tasks. The computer doesn’t have a specific, well-designed purpose.

Question

What are your thoughts on this claim? Do you think that’s true?

I didn’t know you could do that with a computer! – Dan Gutman (1986)

The purpose of a general-purpose computer is to execute programs that operate on data.

Through each program, the computer transforms itself into a machine that performs a specific task.

Computers can calculate sums, but that’s not the only thing they do

🥈 Level 2 – Your software

You use programs for every task that you perform on your computer.

The word software simply means programs.

The word computer applies to all kinds of general-purpose computing devices.

These are all computers

Use the worksheet below to write down some of the programs you know.

Download Level 2 Activity

🥉 Level 3 – Executing a program

Execute the instructions on the intelligent piece of paper, to play noughts and crosses against a human opponent.

This will give you an insight into what it means to execute a program and carry out instructions mechanically.

  • Work in pairs.
  • Draw the noughts & crosses 3⨉3 grid.
  • X goes first and is the mechanical player: follow the instructions blindly.
  • O goes second and is the human player: play as you like and make sure X follows the instructions.
  • Switch roles after each game.
Download Level 3 Activity

📝 Plenary – Concept map

This incomplete concept map contains some of the lesson ideas.

Fill in the missing labels, which specify the relationships between them.

Do this by copying the image into PowerPoint and moving the images around.

In this lesson, you…

  • Learnt that the purpose of a general-purpose computing system is to execute programs
  • Explored what programs are, and looked at specific examples of programs that we often use

Next lesson, you will…

  • Describe the hardware components used in computing systems and how they work together in order to execute programs
  • Highlight how all computing systems, regardless of form, are similar in structure (‘architecture’)

🏅 Level up

🥇 Level 1

  • Complete the Level 1 – The Antikythera mechanism task and upload the Word document to Teams.

🥈 Level 2

  • Complete Level 2 – Your software and upload the Word document to Teams.

🥉 Level 3

  • Complete Level 3 – Executing a program and upload the PowerPoint document to Teams.