IOS

Most firmware is not meant for user interaction and only meant to give hardware life and usealy only uses a few KB in sysetm files

The operating system is what the user uses to interact with the computer and is what executes files and apps, and mangers files and hardware

Utility's give the user many options to change how there system and operating system operates, and change settings

Applications are what the user is most like using for basic functions on there computer including browsers or app stores which are usually added to the operating system for easy use, but you can still download more apps like text documents or games etc..

Hardware is the main brains for the computer, this is what mange's and stores data on your computer, this is everything inside your computer that is physicals, these are the things that you can touch unlike software which is stored on the hardware. Hardware can also be anything inside the compute that helps the overall function of the computer like fans to keep the internals cool.