In the I/O course, we learned about different I/O devices and how they interact with the computer. Importantly, we built a shell, which finally gave non-programmers a way to interact with the computer. We no longer had to write programs to get the computer to do something; we can write commands on the shell.

The shell is an example of the computer program acting as the middle man between the user and computer hardware. Along with the shell, engineers created many tools that help make the computer more user friendly, such as the file system. Some refer to these tools as systems level software. Engineers collected these tools into a single package and started calling it an operating system (OS). Examples of OSs include Microsoft Windows, Apple MacOS, iOS, and Linux.

If you are new to the shell, you may be confused because it appears very different from OSs that you are familiar with. Most of us are used to seeing windows and icons. We interact with them with a mouse or, if it is a touchscreen, with our fingers. Such interfaces are called the graphical user interface (GUI). On the other hand, the shell is a text-based interface, and we primarily use our keyboards to interact with it. Although they appear very different, we can accomplish most of the same tasks. For example, we can load web pages with both text and GUIs (although they would look prettier in the GUI).

In this course, we will learn how operating systems work. We will explore important components of an operating system, including the shell, file systems, the networking interface, and program execution.

For hands on activities, we will make extensive use of the Logicwalk Operating System (LWOS), which is a simplified version of a real operating system created for educational purpose.