1.5 System Software

Question 1

What does the Operating System do?

Answer 1

Controls the computer’s hardware and software. It allows applications to interact with the hardware

Question 2

Types of user interface

Answer 2

• Graphical User Interface - Windows, Icons, Menus, Pointers (WIMP)
• Menu-driven interface, often used by devices that have a dedicated function e.g. MP3, ATM machines, self-service checkouts
• Command Line Interface
• Voice activated
• Real time, sensors detect inputs

Question 3

Features of CLI

Answer 3

• Little processing
• No need for an expensive graphics card
• Can be faster than using a mouse
• Requires less hard disk storage
• Requires less RAM

Question 4

Memory management and multitasking

Answer 4

• To run a program, a computer must copy it from memory
• Data used by the program must also be copied
• The OS keeps a record of the location of all programs/data
• The OS makes sure not to overwrite any existing programs and data
• When multiple programs and tasks need executing at once the OS decide which one runs first on the CPU and for how long

Question 5

Peripheral management and drivers

Answer 5

• The OS manages inputs and outputs to and from peripherals (hardware outside the CPU e.g. mice, keyboards, printers, displays and digital cameras)
• A device driver is a program that controls peripherals
• Each device communicates with the OS using its own driver
• When buying a new device, the driver will need installing

Question 6

User management

Answer 6

• The OS is responsible for users’ logins and passwords
• It stores them in a file/database

Question 7

What file management does the OS do?

Answer 7

Names, folders, moves, saves, deletes and copies them

Question 8

What does utility software do?

Answer 8

Housekeeping

Question 9

Encryption

Answer 9

Renders data incomprehensible by hackers without the necessary decryption tools therefore preventing unauthorised access to data

Question 10

Compression

Answer 10

Reduces file size so that more files can be stored per unit storage

Question 11

Defragmentation

Answer 11

Orders fragmented storage so that the files and space are grouped correctly. Therefore only user with the necessary defragmentation tools can access completed versions of files stored, so preventing unauthorised access. This also speeds reading and writing if physical distance has to be travelled in the memory (Hard Disk Drive)