Software is a set of instructions and programs that allow computers to perform tasks, with application software, system software, and development software as its main types. An operating system is crucial system software that manages hardware resources and acts as an interface between users and computers, evolving from batch processing to cloud-based systems. Key functions of an operating system include process management, memory management, file system management, device management, security, and user interface provision.

1. Operating Systems
Software

2. What is Software?
• Definition:
• Software refers to the set of instructions, data, or programs used to
operate computers and execute specific tasks.
• It is the non-tangible component of computers, contrasted with
hardware, which refers to the physical devices.
• Importance:
• Without software, most hardware would be non-functional. Software
makes computers useful and capable of running various tasks.

3. Types of Software:
• Application Software:
• These are programs designed to perform specific tasks for
users.
Examples include:
• Productivity Software: Microsoft Office, Google Workspace.
• Web Browsers: Google Chrome, Mozilla Firefox, Microsoft
Edge.
• Media Players: VLC Media Player, Windows Media Player.
• Graphics Software: Adobe Photoshop, GIMP

4. Types of Software:
• System Software:
• This includes the operating system and all utility programs
that manage computer resources at a low level.
Examples include:
• Operating Systems (OS): Windows, macOS, Linux.Device
• Drivers: Software that allows the OS to communicate with
hardware peripherals.Utilities: Disk management tools,
antivirus programs, etc.

5. Types of Software:
• Development Software:
• Tools that developers use to create, test, and maintain other
software programs.
Examples include:
• Integrated Development Environments (IDEs): Visual Studio,
Eclipse, PyCharm.
• Code Editors: Sublime Text, Atom, VS Code.

6. Operating Systems

8. What is an Operating System?
• An operating system is system software that acts as an intermediary
between computer hardware and the computer user.
• It manages hardware resources and provides services for computer
programs.
• An operating system acts as a communication bridge (interface)
between the user and computer hardware.
• The purpose of an operating system is to provide a platform on which
a user can execute programs in a convenient and efficient manner

11. The Evolution of Operating Systems:
• Early OS (1950s-1960s): Batch processing, no interaction with users.
• 1960s-1970s: Introduction of time-sharing systems (e.g., Unix).
• 1980s: Development of graphical user interfaces (e.g., Apple
Macintosh, Microsoft Windows).
• 1990s-2000s: Growth of mobile operating systems, introduction of
networked OS, and popularization of open-source systems.
• 2010s-Present: Rise of cloud-based OS, IoT (Internet of Things)
devices with embedded OS, and advancements in real-time and
secure OS.

18. Functions of an Operating System:
Process Management:
• Handles the creation, scheduling, and termination of processes. It
ensures that each process gets the necessary resources and time on the
CPU.
Memory Management:
• Manages computer memory, allocating space for programs and ensuring
that different programs do not interfere with each other’s memory.
File System Management:
• Manages data storage, including file organization, storage, retrieval,
naming, sharing, and protection of files.

19. Functions of an Operating System:
Device Management:
• Manages device communication via their respective drivers. It controls hardware
peripherals and allocates their usage among various processes.
Security and Access Control:
• Ensures that unauthorized users do not access the system. It protects data and resources
through authentication (e.g., usernames and passwords).
User Interface:
• Provides a way for users to interact with the computer. It can be command-line-based
(CLI) or graphical (GUI).
Networking:
• Manages network communications, facilitating data exchange between computers over
networks.

20. Key Components of OS
• A shell is basically an interface present between the kernel and the
user.
• A kernel is the very core of a typical OS.
• A shell is a CLI (command-line interpreter)/ GUI
• A kernel is a type of low-level program that has its interfacing with
the hardware on top of which all the applications run (disks, RAM,
CPU, etc.).