1. Operating System Overview

An Operating System (OS) is the core software that manages the computer hardware, software resources, and provides services for computer programs. It acts as an intermediary between the user and the computer hardware. The OS ensures the smooth execution of applications and manages the resources of a computer, such as the CPU, memory, and I/O devices.

• Processor (CPU): Controls computer operations and performs data processing. If there is only one processor, it is referred to as the Central Processing Unit (CPU).
• Main Memory: Stores data and programs. It is volatile, meaning data is lost when the computer is turned off. Main memory is also known as real or primary memory.
• I/O Modules: Facilitate data transfer between the computer and external devices like disks, communication equipment, and terminals.
• System Bus: Enables communication among the processor, main memory, and I/O modules.

2. Operating System Objectives and Functions

Objectives of an Operating System:

1. Convenience:
   • The OS simplifies the interaction between the user and the hardware. It provides an interface for users to execute programs, manage files, and control peripheral devices.
   • Example: Command-line interfaces (CLI) like bash or graphical user interfaces (GUI) like Windows and macOS.
2. Efficiency:
   • An OS optimizes the use of hardware resources, ensuring that the CPU, memory, and I/O devices are used effectively.
   • It schedules tasks, manages memory allocation, and handles data storage and retrieval efficiently.
3. Ability to Evolve:
   • The OS is designed to accommodate future enhancements and new technologies without disrupting existing system operations. This involves modularity and flexibility in its architecture.

Functions of an Operating System:

1. Process Management:
   • The OS manages the creation, scheduling, and termination of processes. It ensures that each process gets sufficient CPU time and resources to execute.
2. Memory Management:
   • The OS controls and coordinates the use of memory among various applications. It allocates memory to processes and ensures that no process interferes with another’s memory space.
3. File System Management:
   • The OS organizes, stores, retrieves, and manages data on storage devices. It provides a file system structure that allows for the creation, deletion, and access of files.
4. Device Management:
   • The OS manages hardware devices through drivers, ensuring proper communication between hardware and software.
5. Security and Protection:
   • The OS enforces security policies to protect data and resources from unauthorized access. It ensures data integrity, confidentiality, and user authentication.
6. User Interface:
   • The OS provides interfaces like command-line or graphical user interfaces to interact with the system.