The nine functions of an operating system

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Quick Questions

Shade in the A or B circle for each question.

1. Which of these is one of the nine core functions of an operating system?

A Managing memory

B Writing application source code

2. Which function lets the user interact with the computer using windows, icons and menus?

A Managing peripherals and drivers

B Providing a user interface

3. Which statement is correct?

A The OS has nine core functions, and some run unseen in the background

B All nine OS functions are visible to the user on screen

4. What is the purpose of the OS function 'managing multitasking'?

A To store files permanently on the hard drive

B To let several programs appear to run at the same time

5. Which function checks that only users with the right permissions can open a file?

A Providing system security and managing user accounts

B Managing memory

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1Managing files		AThe OS creates, names, stores, moves, copies and deletes files and folders so data can be found again.
2Handling interrupts		BProviding a user interface
3A function the user sees: the OS gives the user a way to control the computer with windows, icons and menus		CWrong because the OS has nine core functions, including files, memory, multitasking, security and user accounts, not just the interface.
4A function that runs unseen: the OS shares RAM between programs so each has the space it needs		DManaging memory
5The OS has only one job: running the user interface		EWrong because managing peripherals and drivers deals with devices such as keyboards and printers, while managing memory deals with RAM.
6Managing peripherals means managing RAM		FThe OS responds to signals that ask the CPU to stop its current task, runs the matching routine, then lets the CPU carry on.

Definitions

OS functions

Fill in the Blanks

Complete each line of code by filling in the missing parts.

// Saves and organises data on disk os.manage(_____)

// Reacts when a device needs the CPU os.handle(__________)

// Shares RAM between running programs os.manage(______)

// Seen by user: GUI or CLI to control PC os.provide(_________)

// Runs unseen: logins, passwords, rights os.manage(________)

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A FOR n ← 1 TO 8

B OUTPUT functions[n]

C NEXT n

Question 2

A job ← "memory"

B IF job = "memory"

C OUTPUT "Allocates RAM"

D ENDIF

Question 3

A job ← "security"

B purpose ← "draws windows"

C OUTPUT job & ": " & purpose

Question 4

A seen ← "user interface"

B unseen ← "managing memory"

C OUTPUT seen & " runs unseen"

Question 5

A device ← "printer"

B IF driver = TRUE THEN

C OUTPUT "Printer is ignored"

D ENDIF

Answer Key

The nine functions of an operating system

Section A: Quick Questions

A — Managing memory

B — Providing a user interface

A — The OS has nine core functions, and some run unseen in the background

B — To let several programs appear to run at the same time

A — Providing system security and managing user accounts

Section B: Match the Pairs

Managing files → The OS creates, names, stores, moves, copies and deletes files and folders so data can be found again.

Handling interrupts → The OS responds to signals that ask the CPU to stop its current task, runs the matching routine, then lets the CPU carry on.

A function the user sees: the OS gives the user a way to control the computer with windows, icons and menus → Providing a user interface

A function that runs unseen: the OS shares RAM between programs so each has the space it needs → Managing memory

The OS has only one job: running the user interface → Wrong because the OS has nine core functions, including files, memory, multitasking, security and user accounts, not just the interface.

Managing peripherals means managing RAM → Wrong because managing peripherals and drivers deals with devices such as keyboards and printers, while managing memory deals with RAM.

Section C: Definitions

OS functions — The nine jobs of an OS: managing files, handling interrupts, user interface, peripherals and drivers, memory, multitasking, platform for apps, security and user accounts.

Section D: Fill in the Blanks

// Saves and organises data on disk
os.manage(files)

// Reacts when a device needs the CPU
os.handle(interrupts)

// Shares RAM between running programs
os.manage(memory)

// Seen by user: GUI or CLI to control PC
os.provide(interface)

// Runs unseen: logins, passwords, rights
os.manage(accounts)

Section E: Spot the Error

A — An operating system has nine core functions, so the loop must run from 1 TO 9. Using 8 would miss one function.

B — An IF statement in pseudocode needs the keyword THEN at the end of the condition line: IF job = "memory" THEN.

B — Providing system security means protecting data and the system, for example with passwords and permissions. Drawing windows belongs to the user interface function.

C — The user interface is a function the user sees and uses directly. The functions that run unseen include managing memory and handling interrupts. The output should say it is seen.

C — When the correct device driver is installed, the OS can manage the peripheral and the printer works. The OS does not ignore it.