An office worker might have a small hard drive in their work computer if they don’t need to store much data beyond simple text files. However, an independent film editor or a digital artist might need a larger hard drive to fit all the video and image files on their computer. Of course, when we talk in terms of “small” or “large,” we don’t mean physical size. Hard drive size references its capacity, or how much data it can hold. We’ll get to this later!

Just know that hardware components come in all shapes, sizes, and capacities, each with a specific role in the function of a computer system. There are huge gaming “rigs,” and there are tiny laptops and notebooks.

We’ll go over the major components below and talk a little about what each one does.

Motherboard. Besides providing the space for the hard drive, CPU, and other components we haven’t covered yet to plug into, the motherboard is home to BIOS, or Basic Input/Output System, the very minimal piece of software that comes with a computer. When you first turn off a computer, before it loads the operating system, it must boot from BIOS.

The motherboard also provides a place for users to plug in peripherals like a mouse and keyboard. If you look behind any computer tower and see where all the plugs and wires are coming out of, that’s the motherboard! You can learn more about the motherboard’s parts and functions in this guide.
Graphics Card. The graphics card, or video card, is the component that outputs images onto your computer’s display, or monitor. While some motherboards offer built-in, onboard, or integrated video cards, the quality is not as good as that of a dedicated video card that you purchase separately and install onto the motherboard yourself.
High-end graphics cards are most popular among people who value the quality of their computer’s display, namely people like PC gamers or people who work in 3D graphics or digital art.

Power Supply Unit. Remember, computers are electronic, and without power, they can’t run! The power supply unit is the component that converts AC power into low-voltage DC power to run the sensitive components inside your computer. Power supply units come with fans to lower the heat inside your computer, as overheating can affect your computer’s performance and endanger its components.
Hard Drive. Since we’re on the topic of hard drives anyway, let’s explain what these things are. This is probably the most familiar piece of computer hardware for non-tech savvy folks, but don’t fret if you’re not in the know! Basically, a hard drive is a computer’s storage device. If you’ve ever saved a picture from the internet, or saved a Word file in your documents, you’ve placed that data onto your computer’s hard drive.
A hard drive contains various components, such as the spindle, actuator, and platter. On hard disk drives, the platter is the spinning plate of aluminum, ceramic, or glass — depending on what type you have — that stores your computer’s information and performs read/write operations. When we say your computer’s information, we really mean the information on your hard drive since that is where your operating system, and all of your files, are stored.

The amount of data your hard drive can store depends on its capacity. Early hard drives (we’re talking 1950s early) could hold about 5 MB, or megabytes, of data, and they were about as big as an industrial-sized fridge-and-freezer combo unit. Physical bulk aside, 5 MB is about the size of one MP3! It’s nothing. More recently, hard drives have become much smaller in physical mass and can store huge amounts of data, ranging from about 250 to 500 GB, or gigabytes, for the average computer user, to 1 TB, or terabyte, for the power user. One terabyte is 1,048,576 megabytes!

Recently, solid-state drives have been increasing in popularity. Unlike hard disk drives, solid-state drives don’t contain any moving, spinning parts, making them a quicker and more reliable way to store your data and improve your computer’s overall performance. They’re also super quiet! Solid-state drives are popular among PC gamers. Check out this guide on how to build a gaming computer for more information.

Central Processing Unit. The “brain” of your computer, the central processing unit — also referred to as the processor — does exactly what its name suggests: it processes all of your computer’s functions. Processors are small, square components with pins and connectors on one side that let you plug them into the CPU socket on the computer’s motherboard. Because CPUs need to calculate and process so much information, most come with a heat sink and a fan to keep the component cool.
The type of hardware you have installed is generally known as your computer’s specifications.

While you don’t need to know how to build your own computer from scratch, understanding what hardware does will help you troubleshoot issues.

2. Selecting the Right Peripherals
Chief Focus: Monitor, Mouse, Keyboard

So you can have a hard drive, motherboard, CPU, graphics card, and power supply unit, but without peripherals, your computer is useless. Peripherals are the physical hardware that allows computer users to interact with the computer.