Systems software and operating systems · GCSE Computer Science

Hardware and software

Hardware is the physical parts of a computer. Software is the programs that run on it.
System software runs and looks after the computer itself: the operating system and utility programs. Application software lets users do tasks, such as a word processor, a web browser or a game.

Memory management and multitasking: shares RAM between the programs that are running, and uses virtual memory when RAM is full.
Processor management: decides which program gets the CPU's time, so several programs seem to run at once.
Device (peripheral) management: uses device drivers to communicate with hardware such as printers.
User interface: lets people use the computer, such as a graphical user interface (GUI) or a command-line interface.
File management: organises files into folders, and lets users create, name, move, copy and delete them.
User and security management: user accounts, passwords and access rights.

Utility programs help to maintain the computer: defragmentation, compression, encryption, backup and anti-malware software.
Defragmentation moves the parts of files on a hard disk drive so they are stored next to each other, which makes them faster to read. SSDs don't need it: they can reach any location equally fast.

A device driver is software that lets the operating system communicate with a particular hardware device.

Hardware: The physical parts of a computer system.
Software: The programs that run on a computer.
System software: Software that runs and maintains the computer, such as the operating system.
Application software: Software that lets users do tasks, such as a web browser.
Operating system: The system software that manages the hardware, software and users.
Utility software: Programs that help to maintain the computer, such as backup or defragmentation.
Device driver: Software that lets the operating system communicate with a hardware device.
Defragmentation: Reorganising a hard disk so the parts of each file are stored together.