Operating Systems (Lecture 1)

Chapter Summary: Introduction to Operating Systems

Introduction

Operating systems (OS) are fundamental components of modern computing systems, serving as the interface between users and hardware. The significance of OS lies in their ability to manage hardware resources and provide a user-friendly environment for executing various applications. This chapter introduces key concepts such as system calls, processes, threads, scheduling, input/output (I/O), memory management, and file systems. Each of these elements plays a crucial role in the efficient functioning of a computer system. The curriculum, as outlined in the CSC311 course taught by Nathan Naidoo, emphasizes practical implementation of operating system tasks and algorithms in the programming language C.

Key Vocabulary Terms

• Operating System (OS): The software that manages computer hardware and provides services for application software.

• System Calls: Interfaces through which a program requests services from the OS.

• Processes: Instances of programs in execution, requiring resources such as CPU and memory.

• Threads: Smaller units of a process that can be executed concurrently.

• Scheduling: The method by which OS allocates CPU time to processes.

• I/O Management: Handling of input and output operations.

• Memory Management: The process of managing computer memory and ensuring efficient use of resources.

• File Systems: The methods and data structures that an OS uses to manage files on a disk.

Course Structure and Assessment

The course assessment comprises:

• Three Practicals (40%): Individual assignments focusing on hands-on tasks.

• One In-Person Test (40%): An assessment of theoretical knowledge.

• Several Pop Quizzes (20%): Short, unannounced quizzes to test comprehension of the material.

Importantly, there is no final exam, emphasizing continuous assessment through practical work and quizzes.

Lecture Schedule

The course is structured into several key topics, including:

1. Introduction to Operating Systems

2. Process Management and Interprocess Communication

3. CPU Scheduling

4. Memory Management (Main and Virtual Memory)

5. File System Management

Each lecture builds upon the previous topics, ensuring a comprehensive understanding of operating system concepts.

Operating Systems: Definitions and Functions

Operating systems are not universally defined, but a comprehensive approximation could be summarized as "everything a vendor ships when you order an operating system." The kernel, which is the core component of an OS, is responsible for managing system resources. Other components include system programs and application programs. Modern operating systems also incorporate middleware, which provides application developers with additional services.

Computer System Structure

A computer system comprises four key components:

• Hardware: The physical devices, including CPU, memory, and I/O devices.

• Operating System: Manages hardware resources and provides an environment for applications.

• Application Programs: Software that utilizes system resources to solve specific problems.

• Users: Individuals or machines interacting with the system.

Key Concepts in Operating Systems

Process Management

Processes are the active entities within an operating system, composed of program instructions and required resources. Key activities in process management include:

• Creation and termination of processes.

• Synchronization and communication between processes.

• Deadlock handling, ensuring processes do not wait indefinitely.

Memory Management

Effective memory management is critical for executing programs. Responsibilities include:

• Tracking memory allocation and deallocation.

• Deciding which processes to load in memory.

• Moving processes between memory and secondary storage as needed.

I/O Management

Operating systems manage I/O operations through device drivers that translate hardware requests into actionable commands. The I/O management system handles:

• Buffer caching to optimize performance.

• Scheduling and management of I/O requests.

File System Management

The OS provides a logical view of storage, abstracting physical properties into files. Activities include:

• Creation and deletion of files and directories.

• Manipulation of files and their mapping onto storage media.

• Backup and recovery strategies.

Resource Allocation and Protection

An OS must ensure resources are efficiently shared among multiple users and processes. Key functions include:

• Resource allocation: Distributing CPU cycles, memory, and storage among active jobs.

• Protection and security: Safeguarding data from unauthorized access while enabling user control over their resources.

Real-World Examples and Opinions

The text emphasizes the evolution of operating systems, citing the transistor count growth from 92 in a 1953 machine to 146 billion in the 2023 AMD Instinct MI300A. This growth exemplifies the complexity and capability of modern computing systems.

Conclusion

In summary, the chapter underscores the vital role of operating systems in managing computer resources and providing an environment for application execution. Understanding OS principles, such as process and memory management, I/O handling, and file system operations, is essential for any computer science student. The practical focus of the CSC311 course ensures students not only learn theoretical concepts but also apply them in real-world programming tasks, preparing them for future challenges in the field of computer science.