This is the software that makes the computer's hardware available to users and to Application software. Applications software is things like word processors, spreadsheets, web browsers
user interface
memory management/multitasking
peripheral management and drivers (peripherals are things connected to the computer eg keyboards, mice, cameras, speakers, mics, printers)
user management
file management
encryption software
turning data into code so that other people can't access it
defragmentation
bringing fragments of files together on the hard drive to make them quicker and easier to access
data compression
reducing the size of a file so it takes up less space on the drive or when transmitted
Small programs that control particular items of hardware device that are attached to a computer.
new driver are installed automatically or manually when you attach new devices to the computer