01. Operating System Overview
Operating System Overview
1. Basic Concepts, Characteristics, and Functions
- Operating System (OS): System software that manages and controls computer hardware and software resources, providing interfaces and services for users and applications
- Characteristics: concurrency, sharing, virtualization, asynchrony
- Functions: process management, memory management, file management, device management, user interface
2. Development and Classification
- Development history: manual operation → batch processing → time-sharing → real-time → network → distributed → embedded
- Classification: batch systems, time-sharing systems, real-time systems, network/distributed/embedded operating systems
3. Runtime Environment
- Kernel mode and user mode: privilege distinction between OS core and user programs
- Interrupts and exceptions: control transfer caused by external/internal events
- System calls: interface for user programs to request OS services
4. OS Architectures
- Monolithic kernel, microkernel, layered, modular architectures
Exercises
- Briefly describe the main functions of an operating system.
- What are the basic characteristics of an operating system?
- What are the main stages in the development of operating systems?
- What is the difference between kernel mode and user mode?
- What is a system call?
Reference Answers
1. Main functions
Process management, memory management, file management, device management, user interface
2. Basic characteristics
Concurrency, sharing, virtualization, asynchrony
3. Development stages
Manual operation, batch processing, time-sharing, real-time, network, distributed, embedded
4. Kernel mode vs. user mode
Kernel mode has higher privileges and can execute privileged instructions; user mode has lower privileges and cannot directly access hardware
5. System call
The interface for user programs to request OS services