In order to pique curiosity, put the question “What makes a computer a computer?” on the board and ask learners to discuss. This discussion should stimulate thinking around software, hardware, form, function and purpose.
Explain to students that a single computer system comprises both hardware and software working together.
Computer software can be application software, system software or utility software.
An operating system is just one type of software, but it is the central one. Its role in a computer system is the management of resources and hardware operations. Users and software applications need the services of operating systems in order to make system calls and to use application programming interfaces (APIs). Users interact with a computer operating system through the computer interface, which on most computers is a graphic user interface (GUI).
In summary, an operating system allows user interaction with computer systems by acting as an interface between users or application programs and the computer hardware.
Computer hardware may be an input, output, storage or processing component, such as a central processing unit (CPU). Have students give an example of each of these components.
The CPU takes data and instructions from the storage unit and makes calculations based on the instructions given and the type of data provided. It is then sent back to the storage unit. The CPU includes the arithmetic logic unit (ALU) and the control unit.
Provide a brief overview of the fetch–execute cycle, described below.
In the fetch–execute cycle, three major sections of a CPU work together. These are the registers (address register, program counter, instruction register, data registers and accumulator), the ALU and the control unit.
All these sections work to the drumbeat of the system clock at billions of times per second. The speed is measured by the clock speed of the computer, now typically around 3 Gigahertz or 3 billion cycles per second.
A single machine cycle proceeds as follows:
Role-playing a machine cycle
This lesson covers the roles of hardware and software in managing, controlling and securing the movement of and access to data in networked digital systems. It first examines the operation of the CPU in the fetch–execute cycle. It then examines the functions of devices that enable networked communications between computers.
Students gain an appreciation of the ‘small picture’ examination of the operation of a computer and later the ‘big picture’ examination of large-scale networking.
You could also focus on the skillset and mindsets that learners mind need to adopt and use during this project, this ties in with the Creative and Critical Thinking Capabilities.
Prepare a lucky dip of these terms. Duplicate sufficient for each student to receive one. Students with identical terms form groups to research that term together. Students research the main function of the item and when it was invented.
Students present to the class the results of their research for each of the items. Ask students with the physical components to present first, followed by those researching protocols.
The following indicates the level of detail expected from the student lucky-dip research.
Explain: First introduced in 1973, TCP is what applications use to communicate with one another. It was created to unify the many networking protocols. The web browser communicates with network software using TCP. TCP breaks down the data communicated between applications into packets so that IP can send them to another computer. IP is the communication that takes place between computers. It is IP that actually sends packets between computers and routes them to their correct destination. TCP reassembles the packets once delivered by IP.
(Note: How Does the Internet Work is a useful diagram.)
Students view the episode: The Internet: Packets, Routing and Reliability, part of the excellent expanding video series produced by code.org. The role-play is repeated now that the functions have been clarified and better understood.