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• A computer system contains both system software and application software.
• The two software types are application software and system software.

Application Software

• Designated software that is made to carry out a specific task or number of related tasks.
• Includes:
  • Word processing software programs such as Microsoft Office Word 2013
  • Spreadsheet Software programs such as Microsoft Office Excel 2013

System Software

• Software that allows computer hardware to work together, also it allows the user to install and run application software.
• Examples include:
  • Microsoft Windows 11
  • Macintosh OS 15.1 Sequoia
  • Linux Mint 22
  • IOS v 18
  • Google Android 15 (Vanilla Ice cream)
• Computer systems need an Operating System to work, laptops/smartphones/desktops are useless without one
• An OS is like an engine in a car

Basic Functions of an OS

• Provides a User Interface
• File Management
• Process Management
• Memory Management
• Input & Output (device) Management

General-Purpose OS

• General-purpose OS is software that allows a computer to run many different applications at the same time and they can be used on different hardware setups.
• Examples include Windows, macOS and Linux operating systems
• A game, a web browser, a word processor and a spreadsheet can be executed at the same point in time.
• A general-purpose OS can run on different hardware configurations such as desktop computers and servers.

Embedded OS

• System software that controls a specific device or machine.
• Unlike the operating system on a computer or phone that can run several applications, an embedded OS is designed to manage one task or a group of related tasks.
• Examples:
  • Software in a microwave lets you set the timer and heating level
  • The system in a washing machine controls the wash cycles
  • The program running on a smart thermostat adjusts the temperature automatically
  • An Anti-lock Braking System (ABS) controls the ABS to prevent wheels locking during sudden braking for car control
  • Infotainment Systems power the touchscreen, navigation, music, and bluetooth connectivity, making driving enjoyable
  • Advanced Driver Assistance Systems (ADAS): Features like lane departure warnings and automatic emergency braking on embedded systems help monitor the road and assist the driver.

General Purpose Operating System vs Embedded Operating System

• General Purpose OS is designed to manage a wide range of tasks, while Embedded OS is tailored for specific functions within larger systems
• General Purpose OS requires powerful hardware (more memory, a multi-core CPU and more storage capacity) to support multi-tasking, while Embedded OS requires less powerful hardware (less Memory (RAM), a single core CPU and less storage capacity)
• General Purpose OS is not so efficient in hardware use, while Embedded OS is very efficient
• General Purpose OS supports many programming languages for flexible programming development, while Embedded OS is designed for specialized devices, often prioritizing low power consumption
• General Purpose OS are used in desktop computers, laptops, servers, while Embedded OS prioritize real-time processing

Single Task vs Multitasking OS

• A single task operating system can only execute one task at one point in time
• A multitasking operating system can execute or run multiple processes / tasks at one point in time.
• MS-DOS is an OS that can run only one program at one point in time, unlike a multi-tasking OS such as Windows 10 that can run many programs at the same point in time

Purpose of an Operating System (OS)

• Managing of the device's resources such as the CPU, memory, storage, and I/O devices
• Establish a user interface
• Running applications software
• An Operating System manages the computer's / devices resources which are CPU, memory, storage, and I/O devices.
• CPU management / Process Management: OS ensures each program(process) in a multiprogramming environment receives an acceptable share of CPU processing time
• Memory Management / RAM management: The OS oversees allocating and removing de-allocating memory to programs in a multi-programming environment.
• Storage management / Management of Files: Managed by the use of a file system creating files/folders to store them on a storage device, allowing arrangement into folders (ex: a folder called Python programming)
• I/O Devices management: Hardware capabilities are maxed out by installing device drivers.
• A device driver is a program that connects an OS and a SPECIFIC hardware component like the CPU to communicate.
• An operating system such as Windows 11 provides a user-interface.
• User interface enables the opening of files/folders/programs, for using the computer

File Management

• Needed to install programs and create files/folders, meaning progress can be saved while using a program

Process Management

• Ensures enough CPU time (time slices) are fairly given to the processes

Process vs Program

• A program is several lines of code that solves a specific task, like many lines of code and data that are found on a secondary storage device
• A process is a program is found in memory to be executed by the CPU, or by being created by the OS to execute a computer program

Memory Management

• the OS allocates enough process memory
• when a program is closed memory is de-allocated

Input & Output (device) Management

• Accurately manages the flow of data to and from external peripherals such as keyboards, mice, and monitors.
• User commands are accurately interpreted by the system.
• After managing system resources, application software can be installed and run after OS installation

Define User Interface (UI)

• A group of elements such as menus, icons and buttons that allow a user to communicate with a computer.

Types of User Interface (UI)

• Command Line Interface (CLI)
• Graphical User Interface (GUI)
• Natural User Interface (NUI)

Command Line Interface

• A text-based interface that allows users to interact with a computer system by typing specific commands
• Requires command knowledge and syntax
• Used for system administration, programming, and managing servers.
• Uses few resources

Graphical User Interface

• A visual interface that allows users to interact with a system through graphical elements such as windows, buttons, icons, and menus
• Is user-friendly and easy to navigate.
• Supports use of mouse, touchpad, or touchscreen
• Requires more system resources than CLI
• Is intuitive for non-technical users
• Example :Windows OS, macOS, web browsers

Natural User Interface

• Enables users to interact with a system through intuitive, natural actions like gestures, voice commands, touch, and body movements
• Designed to feel natural and imitate real-world interactions.
• Uses technologies like speech recognition, gesture detection, and motion sensing.
• Needs advanced computer hardware and software.
• Enhances accessibility for users with disabilities. Examples: Touchscreens on smartphones, voice-controlled digital assistants like Alexa or Siri, and motion-based gaming systems

Distinguish between different UI types

• User needs (user experience vs limitations in functionality)
• System resources needed

Command Line Interface (CLI) vs Graphical User Interface (GUI) vs Natural User Interface (NUI)

• User Experience: CLI needs command syntax vs GUI is intuitive and easy to use and accessible for beginners; NUI Feels natural and immersive with Minimal learning and is excellent for users with disabilities
• Limitations in Functionality: CLI is ideal for complex tasks, limited to textual input/output. GUI limits advanced, low-level control; NUI requires specialized hardware
• System Resources Needed: CLI needs minimum resources vs GUI needs more (RAM, CPU, and a GPU). NUI demands significant hardware such as sensors/cameras

Filing System Definition

• A software mechanism that specifies the way an operating system manages, organises, and accesses files and folders on storage devices.

Filing Systems Types

• FAT32
• NTFS
• APFD
• EXT4

File System in Practice

• Used when setting up a storage device such as a hard disk drive or an SSD, for when partitioning

Operating System Compatibility with File systems

• Windows available file systems NTFS and exFAT; macOS APFS; Linux EXT4
• exFAT used when cross-platform compatibility / software compatibility is a high priority
• APFS is recommended for modern macOS systems with file encryption and compression
• EXT4 is often used due to its stability and performance
• EXT4 on Linux may be preferred for System Performance and Stability

Security and Encryption with File systems

• NTFS or APFS might be chosen for their encryption capabilities.
• FAT32 or exFAT are suitable for sharing files across different operating systems.

CPU process scheduling

• Manage the allocation of CPU time in time slices between multiple processes competing for execution

Round Robin Scheduling

• In a specific order, each process in a multi-programming environment is given a fixed amount of time, or a time slice, each getting an equal share of CPU time

Priority Scheduling

• The OS executes processes based on a set priority, and so tasks with a higher priority get executed before tasks with a lower priority

Round Robin Scheduling vs Priority Scheduling

• Order of execution in Round Robin is in a specific order based on time slices, but in Priority scheduling it is priority based
• Round robin is always pre-emptive where a CPU can interrupt a process after a time slice expires vs priority scheduling that be pre/non-preemptive
• Round robin ensures all time slices are fair vs priority scheduling that does not
• Round robin is suitable for time sharing systems but priority scheduling is suitable for critical tasks

Use of Filing Systems

• File and folder creation and naming.
• The file system stores details, including:
  • File Name: Files group according to name in ascending or descending order.
  • Date Modified: Specifies the date edited
  • File Type: Files group by category such as presentation, word processor, spreadsheet, and executable files.
  • File Size: Files are grouped by size (ascending/descending).
  • Date Created: Files are sorted in order of creation.

Benefits of Filing Systems

• Rapid Data: A user can insert similar files into separate folders, increasing file organization with example of music or vacation pics
• Data organisation: Files easily searchable because each file CAN be grouped thus increasing performance
• Compatibility: Provide a standard method for applications to read/write data
• Scalability: File systems can easily scale with data found across multiple devices

Virtual memory

• An important memory management technique used by OS to create an illusion of larger main memory than what is physically available

Memory Extension

• Allows applications to more memory than installed with a portion of hard disk space as RAM (Random Access Memory) for big or many applications

Device Drivers

• Hardware specific software which helps hardware perform to its greatest by enabling communication (ex: CPU and motherboard)

Buffering

• CPU data is sent at a faster rate to devices than the rate they can process
• Buffering compensates for the speed difference with temporary storage in RAM
• Buffers compensate for speed differences between the CPU and slower devices. It allows both the CPU and the device to operate within rate/speed constraints

System Utilities

• Programs that perform maintenance routines for computer operation, may be installed with the OS or purchased separately
• Example: MS provides Windows Defender

System Utilities

• Anti-virus Programs/ Anti-malware Package: Detect, quarantines and removes know viruses
• Backup Utility: Takes copy of selected files/folders to prevent permeant data loss
• Restore Utility: Program returns a computer system to a previous working state
• Disk Management
  • Cleanup: Storage is by removing unnecessary files to improve system performance/efficiency
  • Disk defragmenter: Reorganizes data so that files are stored together
• File Compression: Reduces one or more file sizes for storage/transmission purposes
• Formatting utility: Prepares storage devices to be used by creating a file system.

System File Compressions

• Formatting utility: Creates a file system
• Program Installer Utility- Facilitates installation of applications via step-by-step guide and oversees licensing and location
• Compatibility between CPU bit size, OS bit size, and software bit size
• To achieve the best results with no errors

Compatibility

• Operating System bit size, the CPU word-length and application software bit-size must all be compatible
• A 32-bit application program can run on a 64-bit operating system or in turn supported by a 64-bit CPU
• a 32-bit computer can be supported by a 64-bit OS but not vice versa