What does an operating system do?
The purpose and functions of the operating system: user interface, memory management and multitasking, peripheral management and drivers, user management, and file management.
An OCR J277 1.5.1 answer on the purpose and functions of an operating system: the user interface, memory management and multitasking, peripheral management and drivers, user management, and file management.
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What this dot point is asking
OCR wants you to state the purpose of an operating system and to describe its functions: the user interface, memory management and multitasking, peripheral management with drivers, user management, and file management. A common exam question asks you to name several functions or to explain a couple in detail, so learn each precisely.
The purpose of an operating system
User interface, memory and multitasking
Peripherals, users and files
Why these functions matter
The operating system is what turns a collection of hardware into a usable computer. It lets many programs share one processor and memory without crashing into each other, lets one design of computer work with countless different printers and devices through drivers, keeps each user's files and settings separate and secure, and gives a consistent way to find and manage files. In the exam, be careful to name OS functions (managing the machine) rather than application tasks (doing work for the user), because that distinction is exactly what is tested.
Try this
Q1. State three functions of an operating system. [3 marks]
- Cue. Any three of: user interface, memory management, multitasking, peripheral management (drivers), user management, file management.
Q2. State what a device driver does. [1 mark]
- Cue. It is software that translates between the operating system and a specific device so the device works correctly.
Q3. Explain what memory management involves. [2 marks]
- Cue. Allocating RAM to each running program and keeping their data separate, freeing memory when programs close, and managing virtual memory.
Exam-style practice questions
Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
OCR 20214 marksState four functions of an operating system.Show worked answer →
Award one mark for each correct function, up to four. Any four of:
Providing a user interface (so the user can interact with the computer, for example a graphical desktop).
Memory management (allocating RAM to programs and keeping their data separate, and managing virtual memory).
Multitasking (managing several programs running at once by sharing processor time between them).
Peripheral management using device drivers (controlling input/output devices such as printers and keyboards).
User management (handling user accounts, logins and access rights).
File management (organising, naming, saving, moving and deleting files and folders).
Markers reward four distinct, correctly named functions. Naming an application task (such as "writing a document") is wrong.
OCR 20224 marksExplain what is meant by memory management and by peripheral management, both carried out by the operating system.Show worked answer →
Memory management (2 marks): the operating system allocates areas of RAM to each running program and keeps their data separate so they do not interfere with each other; it frees memory when a program closes and manages virtual memory, moving data between RAM and disk when RAM is full.
Peripheral management (2 marks): the operating system controls the input and output devices (peripherals) connected to the computer, such as printers, keyboards and monitors, using device drivers. A driver is software that translates between the operating system and a specific device so the device works correctly.
Markers reward "allocating RAM to programs and keeping it separate" for memory management, and "controlling peripherals using drivers" for peripheral management, with a definition of a driver.
Related dot points
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An OCR J277 1.5.2 answer on the purpose of utility software and the specific roles of encryption software, defragmentation software, data compression and backup utilities, including full and incremental backups.
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An OCR J277 1.2.1 answer on the need for primary storage, the purpose and characteristics of RAM and ROM, the differences between them, and why virtual memory is needed.
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An OCR J277 2.5 answer tying the topic together: source code versus machine code, why translation is needed, how language level (high or low) is chosen, and how an IDE supports the whole process of writing, translating, running and debugging software.
Sources & how we know this
- OCR GCSE (9-1) Computer Science (J277) specification — OCR (2020)