How do software and hardware work together?

Software and hardware work together thanks to the cooperation of your operating system and central processing unit. Your operating system acts as an interface between you and your CPU which is the brains of your computer. It allows you to deliver instructions to various devices on your computer using things like your keyboard and mouse.

Without the cooperation of software and hardware, your computer would essentially be a large paperweight. The hardware is typically what we interact with but it's the software that is the driving force behind how we use our devices.

The stylish and simplistic interface of Apple or the open and customizable Android UI would be nothing if our hardware and software did not work together.

To explain how software and hardware interact I’ll first define what they are and then dive into how they work together. I’ve seen this answered before and all of the answers become too abstract and use strange examples. Let’s try and avoid that and not start writing 1s and 0s to illustrate my point.

What is computer software?

Reporting software displayed on a tablet

Software is just a cluster of instructions that tell a computer how to function. We can generally split software up into three categories:

System software

System software sits between your hardware and application software. It is your operating system, so think Windows, Android, or macOS. It abstracts away all of the tasks needed to run a computer so as a user you don’t have to write code every time you want to do something.

Utility Software

Utility software is run in the background by the system software and performs specific tasks. Antivirus software and programs that clean up old files are good examples of utility software.

Application Software

Application software is the type of software most of us are familiar with. Think of word processors, browsers, games, photo editors, and any other app on your laptop or computer.

The majority of your software is kept on your hard drive except for when your computer first starts and your system software which is booted on RAM. People get too technical with their definitions of software. At a basic level software is just the apps you use on your devices.

What is computer hardware?

A close up photo of a computer ciruit board

Computer hardware is the parts of your computer that carry out the instructions created by the software. Hardware is the physical parts of a computer and includes the motherboard, CPU, webcam, monitor, and even game controllers. The hardware is the nut and bolts of your device, the physical product.

There are a few main types of hardware devices that include:

  • Input devices - webcam, microphone
  • Output devices - monitor, speakers
  • Processing devices - CPU
  • Storage devices - hard drive, flash drive

As a user, you only tend to interact with the input and output devices with the other devices being controlled by the CPU behind the scenes.

How do software and hardware work together?

A diagram showing how hardware and software work together

Hardware and software are able to work together because of your operating system and CPU. Your operating system acts as an interpreter between you and the central processing unit which is the brain of your computer. It abstracts away instructions so that you don’t have to continually write code to use your hardware devices.

When you start your computer the operating system is first loaded onto the RAM, which is a storage device, and then executed. From there the rest of the operating system is then booted and your device springs to life.

Your CPU is the brain of your computer. It is in charge of sending and receiving instructions to other parts of the system and creates the instructions that other devices interpret and use to function. Without your CPU there is no functioning link between your hardware and software. Your CPU:

  1. Reads the program counter
  2. Loads instructions from the RAM
  3. Decodes instructions
  4. Executes instructions and sends to other pieces of hardware
  5. Increments the program counter and repeats

As users we don’t manage the CPU directly, we use our operating system to do this. When we launch Word, our operating system tells the CPU we need an application received from storage. When we play a song our operating system informs the CPU that our speakers need to emit sound.

Information generally flows from users toward the CPU. For example, we move the mouse or type on the keyboard in a Word document it is sent as instructions via your operating system to the processor.

Your application software (Word) corresponds with your system software (Windows or macOS) which then communicates with your hardware (CPU). From here, the processor can talk directly with other pieces of hardware using traces on the motherboard.

Essentially every operating system is just a layer of abstraction on top of the CPU so that we can tell a computer what to do. There are more elements to it but this is a simplistic way of looking at things.

​​What lets the hardware and software work together?

It is your computer’s operating system coupled with the central processing unit that allows your hardware and software to work together. The processor is the brain of the computer and without it controlling hardware would be impossible. Similarly, without system and application software, you wouldn’t be able to run any apps on your device.

Without the operating system to act as an intermediary between you and your processor, you would have to directly run everything through the command line. Changing settings on your hardware would be significantly more difficult without your OS to help. Likewise, it is your CPU that is in charge of creating and distributing the necessary instructions that let you use your input and output devices.

The relationship between software and hardware

Software and hardware are intimately linked. In the context of a computer, one doesn’t exist without the other. Having hardware without any software would be like a car without wheels and an engine. The physical device would be there but it would not be capable of doing anything.

Device Drivers

The piece of software that helps hardware devices interact with an operating system is called a device driver. A device driver is a specialized program that acts as a bridge between a hardware device and the operating system. It allows the operating system to communicate with the hardware which enables the device to send and receive data from the computer.

Device drivers are specific to the type of hardware they are designed for, and different types of hardware devices require different drivers. For example, a printer driver is required to enable a printer to communicate with the operating system, while a graphics card driver is required to enable a graphics card to function properly.

Device drivers are typically installed automatically when the hardware device is first connected to the computer, or they may be included on a CD or provided as a download from the manufacturer's website.

If you use an old operating system or haven't updated the version in a long time you may find that some of your hardware doesn't work. The reason for this is that the hardware doesn't have a specific device driver for the older operating system.