Introduction
1. Basic concepts
concept
The operating system is a collection of programs that controls and manages the hardware and software resources of the entire computer system, rationally organizes and schedules the computer's work and resource allocation, and provides convenient interfaces and environments for users and other software. The operating system is the most basic system software in the computer system.
feature
Concurrency: two or more events occur within the same time interval
Sharing: mutually exclusive sharing mode, simultaneous access mode
Virtual: turning a physical entity into several logical counterparts
Asynchronous: the execution of a process is stop-and-go
concurrent and sharing are mutually existing conditions. Without concurrency and sharing, virtuality and asynchronousness cannot be discussed.
Goals and functions
- Manager of computer system resources:
processor management, memory management, file management, device management - The interface between the user and the computer hardware system
Command interface, program interface - Used as an expansion machine
2. Development and classification
Manual operation stage (no operating system at this stage)
Batch processing phase (operating system starts to appear)
Single lane batch processing system
Multi lane batch processing system
time-sharing operating system
Allocate processors to online jobs in turn according to time slices
real-time operating system
Such as controlling a rocket launch system
Network operating systems and distributed computer systems
personal computer operating system
3. Operating environment
Operating mechanism
Clock management, interrupt mechanism, primitives