Applied Computing

Introduction to Computer Networks

Networks

In the simplest form a computer network is two devices cinnected together. For example, a computer and a printer or a remote control and a television. These two NODES are sharing data over a wired or wireless transmission medium. They also follow rules, called PROTOCOLS, that define how the data is transmitted to ensure communication is successful.

ARPAnet

In 1969, one of the first demonstrations of a computer network occurred after eight years of development work. ARPAnet's technology was based on the existing circuit switching process used in the telephone network, but applied it to computer data in a process called PACKET SWITCHING. Their goal was to transmit data between the four computers in Santa Barbara, Los Angeles, Stanford, and Utah.

Structure and Components

Nodes

Each node in a computer network is a hardware device that creates (source node), transmits, forwards, redirects, and/or receives (sink) the data communication.

These can include computers, smartphones, MICROCONTROLLERS, and peripherals. Devices that allow the transmission through a network between sources and sinks include ROUTERS, SWITCHES, and hubs.

Connection

These nodes need to be connected to each other in the network. Not all nodes need to be directly connected to one another as this would be increadibly difficult to set up. Instead as long as there is a path between the source and the sink, via other nodes, data can be transmitted.

This can be done through twisted copper pairs, FIBRE OPTICS, or wireless such as radio waves.

Topologies

How theses connections are arranged between the nodes is called the TOPOLOGY. Different topologies are used in different contexts. Bus and Star topologies are common arrangements.

Skill Builder

Explore a microcontroller - micro:bit

There are many coding environments available for the micro:bit but we will use the micro:bit Python editor.

Go to the micro:bit Python Editor
Run the default code in the simulator on the right. What does it do?

3. Using the code reference library on the left, attempt to create your own simple program that takes an input, and produces an output. For example, when you press a button, something is displayed on the LED matrix. The refernce library has example code that you can copy and paste.

4. First run the program in the simulator to test, then connect your micro:bit via the USB to your computer and press 'send to micro:bit' button. This will flash your. program to the micro:bit so you can test your program on the physical device.

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