Software

Question 1

What is an OS?

Answer 1

Operating System.

a complex piece of software found on most computer systems.

Question 2

What are the main functions of an OS? (6)

Answer 2

• Communicate with IO devices vie device drivers
• provide a platform for applications to run on (& a user interface)
• control memory management and allocation
• organise CPU and its processing tasks
• file management and disk management
• manage system security and accounts

Question 3

How does an OS communicate with IO devices?

Answer 3

THROUGH DRIVERS
–every i/o devices connected to a computer system needs a device driver
- when computer boots up -> OS chooses correct driver for the device it detects. (if a new device, may install a new driver)
- updates may be installed automatically by OS or manually by user
(device manufactures may release updates to fix bugs or improve performance)

Question 4

How does an OS manages applications?

Answer 4

• OS allows applications to access hardware and, if needed, RAM or secondary storage.
• OS provides a user interface for applications.
• applications usually written for a particular OS and takes advantage of its features.

Question 5

How does an OS interact with memory?

Answer 5

when an application is opened, OS copies necessary parts of application to memory ->then additionally parts when needed.
-OS manages how much RAM a program has access to-> depends on the program (eg image editing uses a lot of memory vs text editors need much less RAM)

Question 6

How does an OS multitask with applications?

Answer 6

OS’s allocate certain memory addresses to every application running so they don’t interfere with each other or overwrite each other.

Question 7

How do CPUs execute every process an application needs ?

Answer 7

CPU’s can only run one process at a time.
OS use scheduling to determine the most efficient order of processes for the CPU.
all the processes are allocated ‘priorities by OS.

To multitask-> CPU switches between processes rapidly

Question 8

What is file management?

Answer 8

organization of data into usable hierarchical structure.

also, deals with movement, editing and deletion of data.

Question 9

How does OS manage hard disks?

Answer 9

• splits disk into storage sectors
• decides which sectors to write data into and tracks the free space
• also, OS uses utility software to help.

Question 10

How do Operating Systems manage system securtiy?

Answer 10

most common way is user account control

• > allows users to access or not access specific data.
• > some users need passwords or pin to access certain data.