Introduction to Operating Systems

Introduction to Operating System (OS)

• Operating System is essential for managing computer hardware and acting as an intermediary between users and hardware.
• GM-NAA I/O, introduced in 1956 by General Motors for the IBM 704, was the first operational OS.
• Different types of OS include Batch, Multi-Programming, Multi-Processing, Multi-Tasking, Time-Sharing, Distributed, Network, and Real-Time Operating Systems.
• Functions of an OS consist of providing interfaces, managing processes, resources, and ensuring security.

Computer System (Hardware) Basics

• Modern computers comprise one or more CPUs and device controllers connected via a common bus to access shared memory.
• Device controllers manage specific devices, allowing concurrent execution between the CPU and device controllers, necessitating a memory controller for orderly memory access.

Other Basics

• The Bootstrap Process initiates when a computer is powered on, locating and loading the OS kernel into memory.
• Interrupts signal events initiated by hardware or software, leading to immediate CPU action redirected to a fixed location for servicing the interrupt.
• System Calls, or monitor calls, trigger software-based interrupts for requesting OS services.

Storage Structure Basics

• Programs must be stored in re-writable memory (RAM) for execution, while static programs are stored in ROM.
• Memory organization allows access via load (moving data to CPU) and store (moving data from CPU to memory) instructions.

I/O Operations

• The OS manages I/O operations through device controllers responsible for local buffer storage and special-purpose registers for device communications.
• Device drivers provide a uniform interface between the OS and device controllers.
• For efficient data transfer, Direct Memory Access (DMA) allows devices to transfer data directly to and from memory, minimizing CPU intervention.

CPU Architecture

• Single Processor Systems use one main CPU to execute general-purpose instructions.
• Multiprocessor Systems consist of multiple processors sharing bus and resources for increased processing power.
• Clustered Processor Systems link multiple systems via a local area network for high availability.

Operating System Structure

• Multiprogramming enhances CPU utilization by organizing multiple jobs in memory, ensuring the CPU remains busy.
• Time-Sharing or Multitasking systems enable user interaction with multiple running programs through rapid CPU switching.

Operating System Services

• Services provided by an OS include program execution, I/O operations, communication between processes, file and memory management, security, resource management, user interface, networking, error handling, and time management.

User Operating System Interface

• Interfaces allow user interaction with the OS through command-line interfaces or graphical user interfaces (GUIs).
• Command-line interfaces enable direct command entry, while GUIs utilize mouse-driven window and menu systems for easier navigation.
• GUIs were popularized in the 1980s with devices like the Apple Macintosh and Microsoft's Windows.

System Call

• System calls provide the means for programs to request services from the OS kernel.
• Types of system calls include process control, file management, device management, information maintenance, and communication functions.

This quiz covers the fundamental concepts of operating systems, including their roles, types, and functions. You'll learn about historical milestones such as the introduction of GM-NAA I/O and how modern computers operate with CPUs and device controllers. Test your knowledge of the bootstrap process and the interactions between hardware and software.