The H.A.C.K.E.R. Project

To plenty of people, computers seem to work like magic. You simply turn them on and begin typing and clicking away, and it all just works. However, there is actually a lot going on behind the screen of your phone or computer that makes all this magic possible. The operating system (OS) is what allows your computer to do its tasks; without an operating system, a computer would be extremely difficult- if not impossible- to use. The OS does a lot in terms of managing the computer, but its function can be generalized to two main roles: a translator and an instructor (Of course, as with many subjects, the OS is a much more nuanced topic, but these two general roles are the basics).

The Operating System: A Translator

The GCFGlobal program has a great article covering basics of what an OS is in terms of being a translator, and they explain the operating system as follows:

An operating system is the most important software that runs on a computer. It manages the computer’s memory and processes, as well as all of its software and hardware. It also allows you to communicate with the computer without knowing how to speak the computer’s language.

GCFGlobal Program

While we may type in English, Hindi, or French, our computers do not actually understand these languages. Being logically driven machines, they operate on a binary basis of 1s and 0s (or, in other words, true and false or on and off). Thus, the OS acts as a translator between us and our system. When we type the letter “A” on the keyboard, a signal is sent to the OS, which then translates our letter “A” into a collection of 1s and 0s. If something goes wrong with a part of our computer, the operating system receives a message of 1s and 0s and then translates that into whatever language we read and write. This allows us to actually use these wondrous machines.

The GCFGlobal program has also created an informative video that covers the basics of operating systems and provides some examples of OSes, which you can find here or watch below.

The Operating System: An Instructor

The OS, however, is not simply a translator that acts as a mediator between us and our machines. It also helps to instruct the computer on how and when to function by “scheduling the work done by the processor” (Franklin & Pollette). The processor (also called a CPU) is, as the name implies, the physical piece of hardware on the computer that processes all of its data. Without a processor, the computer would literally do nothing; in other words, the processor is like the brain of a computer.

There are two specific tasks that the OS attempts to do when managing the processor’s workload. These are to ensure “that each process and application receives enough of the processor’s time to function properly”, and to make sure the processor uses “as many processor cycles as possible for real work” (Franklin & Pollette).

Technically speaking, a processor can only realistically perform one task- often referred to as a process- at a time. However, to us, it clearly appears like our computers are great at multitasking, being able to perform many different functions all at seemingly the same time. This is an illusion; while a single processor cannot multitask in the way we imagine, it can switch rapidly between processes, which makes it seem as if it is multitasking.

As a result, it is up to the OS to ensure that these processes are switched out effectively. This is done through the use of interrupts. These are “special signals sent by hardware or software to the CPU”, “…as if some part of the computer suddenly raised its hand to ask for the CPU’s attention in a lively meeting [or classroom]” (Franklin & Pollette). Basically, a process that needs to run can issue an interrupt to the processor, which tells it to stop whatever it is working on, and switch to this new task. The OS manages these interrupts, making sure that they are handled effectively.

Some processes might be more important- or have higher priority- than others, so the OS will make sure that they are not interrupted unless something even more important occurs. For example, it is important that you eat, so you may choose to not check your text messages while eating, but if a fire starts, you will almost always stop to handle the emergency.

In other cases, some processes might have to wait for some other event to occur. When this happens, the OS may choose to swap out this process for another so that time is not wasted simply waiting for the first process. Using the food example from before, you may put two slices of bread in the toaster and, while those are toasting, start cooking eggs. Once the bread has sufficiently toasted, the toaster will alert you- much like an interrupt- and, once you can step away from the eggs, you can handle the toast.

Types of Operating System

There are many different OSes in use in the world today. The below list contain some of the more well-known OSes:

• Windows
• MacOS
• iOS
• Android OS
• Linux
• Unix
• ChromeOS

Finally, as with any software, operating systems tend to grow and change, receiving updates for security, usability, and other improvements. There may be many different OSes available in the future, or, at the least, new versions of the ones listed above.

Resources & Further Reading

Franklin, Curt, and Chris Pollette. “How Operating Systems Work.” HowStuffWorks, HowStuffWorks, 2000, computer.howstuffworks.com/operating-system5.htm.

GCFGlobal. “Computer Basics: Understanding Operating Systems.” GCFGlobal.Org, GCFGlobal Learning, edu.gcfglobal.org/en/computerbasics/understanding-operating-systems/1/.