Essentially, it’s all the tangible parts that fit together inside your computer case. They include things like a central processing unit, memory and a hard drive.
The hard drive stores persistent storage – storing bytes as files that remain even after the power is turned off. It can use either a traditional spinning disk or the newer solid-state drives.
Motherboard
The motherboard is the skeleton of your computer. It provides an electrical highway for signals to travel, connecting up the components like a CPU socket that holds the actual processor, RAM slots for temporary data storage and expansion slots for peripheral devices. It operates as the command center of your computer by transferring data via data buses that branch off from the Northbridge and Southbridge components in the chipset.
The motherboard distributes power optimally by using specialized circuit technology to ensure each system component gets the amount of electrical current it needs. It also contains the CMOS battery that powers the BIOS (Basic Input/Output System) or UEFI (Unified Extensible Firmware Interface) chip, which initializes hardware and boots the operating system.
CPU
Often found in the center of a laptop or desktop under a cooling fan, the CPU looks like a small silicon chip but packs enormous processing power. It’s the brain of your computer and responsible for carrying out all the instructions that make it work.
The control unit sends a system of electrical pulses to the memory unit, triggering it to execute high-level computer instructions. This process is known as the fetch-execute cycle, and it occurs millions of times per second. The arithmetic/logic unit handles all the math functionality and logical operations (like adding numbers together or comparing them). The memory unit stores the results of these operations, as well as the next instruction to process.
RAM
The RAM is where your computer saves everything it needs to work right away. This includes 20 tabs in your browser and save files from your favorite video game. Without it, your computer would have to dig into its long-term storage (hard drive or SSD) to find the data each time you want to use it.
It also translates incoming web pages and other programs into the CPU’s instructions for execution. Unlike the hard drive, RAM is non-volatile and retains its contents when you shut down your computer. Currently, most computers work with SDRAM (synchronous dynamic random-access memory). A development called DDR lets the RAM send two data transfers during one system clock cycle for much faster performance.
Video Card
A video card (also called a graphics card, display adapter, or video controller) processes some of the complex graphics data going to your monitor and takes some of that load off your CPU. A specialized processor in the card accelerates 2D and 3D graphics rendering for applications such as web browsers, photo editors, and video games.
The cards hold memory for storing image information and completed pictures, as well as a cooling system to keep them cool. They also have ports that connect to monitors, televisions, and projectors. Some have HDMI connections to support multiple outputs at the same time. They follow industry standards to support a wide range of colors and resolutions.
Hard Drive
A hard drive stores applications like Google Chrome and word processing programs internally so they don’t need to be loaded each time you start up your computer. Saved files are also stored on these drives.
HDDs contain double-sided circular aluminum platters coated with magnetic layers where data is stocked and organized in sections called sectors. They spin at a fast rate, and an internal motor moves arm(s) that scan the platters to read the data in binary code (1s and 0s).
While HDDs are still used in most computers, they have been eclipsed by faster and quieter solid-state drives (SSD). If your hard drive fails, you will not be able to use your computer until it’s replaced.
Keyboard
The keyboard is the primary input device on a computer. It contains alphanumeric keys (letters A-Z and numbers 0-9) and other keys that are used for functions like scroll lock, num lock, caps lock etc.
Keyboard switches (also called keyswitches) sit underneath each key and capture electrical impulses when pressed. Different types of switches provide different tactile feedback and actuation force. Keyboards include control circuitry that converts these impulses into key codes and, in the case of detached keyboards, sends them down the serial cable to the main computer processor.
Some keyboards also have arrow keys and a numeric keypad. These can be mapped to specific commands through the keyboard software.