Operating Systems (OS)

What is an operating system?

software that provides an interface between the user and the hardware of a computer system

What are the main functions of an operating system?

• User interface

• Memory management and multitasking

• Peripheral management and drivers

• User management

• File management

What is a user interface?

how the user interacts with the operating system

Examples of a user interface:

• Command Line Interface (CLI)

• Graphical User Interface (GUI)

• Natural Language Interface (NLI)

• Menu

What is a CLI?

• requires users to interact with the operating system using text based commands

• more commonly used by advanced users

• Examples of CLIs are MSDOS (Microsoft Disk Operating System) and Raspbian (for Raspberry Pi)

What is a GUI?

• requires users to interact with the operating system using visual elements such as windows, icons, menus and pointers (WIMP)

• optimised for mouse and touch gesture input

• Examples of GUIs are Windows, Android and MAC OS

What is an NLI?

• uses the spoken word to respond to spoken or textual inputs from a user

• Examples include:

  • Virtual assistants - Amazon Alexa, Google Assistant, Siri

  • Search engines

  • Smart home devices

Advantages of CLI

• Uses less system resources

• Useful for automation of tasks

• Commands are often faster to type than navigating menus

Disadvantages of CLI

• Requires users to remember commands

• Typing errors are common

• Less intuitive than GUI

Advantages of GUI

• Intuitive and user-friendly

• Requires no previous knowledge to use

• Information is visual, making it easier to understand

Disadvantages of GUI

• Uses more system resources

• Can be slower to find and execute commands

• Can be frustrating when doing repetitive tasks

Advantages of NLI

• Can be used by people with disabilities

• Intuitive

Disadvantages of NLI

• Not always reliable

• Privacy concerns

Advantages of menu

• Simplicity

• Efficiency

Disadvantages of menu

• Limited flexibility

• Accessibility issues

What is memory management?

a process carried out by the operating system allocating main memory (RAM) between different programs that are open at the same time

How does the OS manage memory?

• responsible for copying programs and data from secondary to primary storage as it is needed

• Programs and data require different amounts of RAM to operate efficiently and the OS manages this process

• RAM is allocated based on priority and fairness, for example, system applications (essential) may have a higher priority than user applications

• The OS dynamically manages the memory, adjusting allocation as needed to maintain optimal system performance

• Memory management makes multitasking possible

What is multitasking?

a process made possible by the OS simultaneously managing system resources (memory, CPU, etc.) to give a user the perception of being able to use multiple programs at the same time

How does the OS manage multitasking

• The OS splits tasks and allocates system resources based on a priority

• The CPU can only execute one instruction at a time, it can execute billions of them in one second.

• This makes it appear that multiple programs are running at the same time

What is peripheral management?

a process carried out by the OS managing the way peripherals (hardware) interact with software

How does the OS manage peripherals?

• The OS allocates system resources to peripherals to ensure efficient operation

• Peripheral management makes plug-and-play (PnP) functionality possible, automatically detecting and configuring new peripherals without the need for manually installing device drivers or power cycling the system

What is a device driver?

• a piece of software used to control a piece of hardware

• peripherals require device drivers in order to be used by the operating system

• Device drivers are OS specific and are regularly updated

How does the OS make basic compatibility possible and enable plug and play?

The OS has generic device drivers built in

How can hardware be used to its maximum capacity?

In order for hardware to be used to its maximum capacity, often a separate device driver must be downloaded from the manufacturer

What is user management?

• a process carried out by the OS enabling different users to log on to a computer

• The OS is able to maintain settings for individual users, such as desktop backgrounds, icons and colour schemes

•  A system administrator is able to allocate different access rights for different users on a network

What are access rights?

permissions that determine who can access and use specific resources or information

what are some examples of access rights?

• read

• write/modify

• execute

What does read allow the user to do?

read allows the user to look at the contents of the file but not change anything

what does write allow the user to do

what does edit allow the user to do