Application software does a job the user wants done. The operating system (OS) is system software that manages the hardware and provides a platform on which applications run. Questions usually give you a short scenario or a list and ask you to say which is which, or to describe an OS function.
This lesson opens software and systems, and every later lesson reuses the sorting habit you build here.
How do you tell them apart?
Ask one question: is this software doing the user’s task, or looking after the computer?
If it does the user’s task (write, calculate, browse, play, draw), it is an application.
If it looks after hardware, memory, files, users or other programs, it belongs to system software. The OS is the main piece of system software. Utility programs and device drivers are also system software.
What does an operating system do?
These are the functions you should be able to name and explain in one sentence each:
| Function | What it means in one sentence |
|---|---|
| Managing files | Creates folders, stores, names, moves and deletes files on storage. |
| Managing memory | Decides which part of main memory each running program may use, so programs do not overwrite each other. |
| Multitasking | Shares processor time between programs so several seem to run at once. |
| Managing peripherals | Sends data to and from devices such as a printer or keyboard, using device drivers. |
| User interface | Gives the user a way to control the computer, such as windows, icons or a command line. |
| Handling interrupts | Responds when hardware or software signals that it needs attention. |
| Security | Controls user accounts, passwords and access to files. |
Worked example
A student has these items on a laptop: spreadsheet program, printer driver, memory manager, photo editor, antivirus scanner. Sort them into operating system functions, application software and other system software.
Step 1. Ask what each does for the user. The spreadsheet program lets the user calculate: application. The photo editor lets the user edit pictures: application.
Step 2. The memory manager decides which program uses which part of memory. That is looking after the computer, and it is a core job of the OS: operating system function.
Step 3. The printer driver lets the OS talk to a particular printer. It is not a task the user chose: system software, linked to the OS peripheral management function.
Step 4. The antivirus scanner protects the system and is not part of the core OS: utility, a type of system software. You will study these in identify a utility function.
The mistake to watch for
Mistaken answer: “The operating system is the hardware that runs the computer.”
This mixes up software and hardware. The OS is a program. It sits between the hardware and the applications, and it needs the processor and memory to run.
Another weak answer is “the OS makes the computer work”, which names no function. Replace it with a named job: “The OS allocates memory to each running program so they do not overwrite each other.”
Check yourself
1. State two functions of an operating system for a tablet that is running a video app and a messaging app at the same time.
Show answer
Multitasking: the OS shares processor time between the two apps so both appear to run together. Memory management: the OS gives each app its own area of main memory so one does not overwrite the other.
2. Classify each as application software or system software: a music player, a disk formatting tool, a presentation program.
Show answer
Music player: application. Disk formatting tool: system software (utility). Presentation program: application.
3. A user plugs in a new keyboard and it works straight away. Which OS function is mainly involved?
Show answer
Managing peripherals, using a device driver so the OS can send and receive data from the keyboard.
Where this leads next
The next step is to see how a program becomes something the processor can run, in compare interpreter and compiler behaviour. You can test the whole topic later with the software and systems practice set.
Many students can list the functions but struggle to match them to a scenario. A teacher can practise that with your written answers in online one-to-one Computer Science tuition.