MindMap Gallery OS Chapter 1
This is a mind map about the first chapter of OS, which introduces the basic concepts of OS, 0S development, 0S operating environment, etc.
Edited at 2024-01-28 14:25:36One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
Project management is the process of applying specialized knowledge, skills, tools, and methods to project activities so that the project can achieve or exceed the set needs and expectations within the constraints of limited resources. This diagram provides a comprehensive overview of the 8 components of the project management process and can be used as a generic template for direct application.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
One Hundred Years of Solitude is the masterpiece of Gabriel Garcia Marquez. Reading this book begins with making sense of the characters' relationships, which are centered on the Buendía family and tells the story of the family's prosperity and decline, internal relationships and political struggles, self-mixing and rebirth over the course of a hundred years.
Project management is the process of applying specialized knowledge, skills, tools, and methods to project activities so that the project can achieve or exceed the set needs and expectations within the constraints of limited resources. This diagram provides a comprehensive overview of the 8 components of the project management process and can be used as a generic template for direct application.
Operating System Chapter 1
1.1 Basic concepts of OS
What is OS
An operating system refers to 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 then provides convenient interfaces and environments for users and other software. The operating system is the most basic system software in the computer system. The operating system is the core of the software.
OS features
concurrent
Concurrency is the same time interval; it is achieved through time sharing; Parallelism is at the same time; it requires the support of related hardware, such as pipeline or multi-processor hardware environment
shared
Mutually exclusive sharing: critical resources, resources that only one process is allowed to access within a period of time, critical resources are required to be mutually exclusive shared; simultaneous access: disk devices;
virtual
Time division multiplexing technology-multiple CPU space division multiplexing technology-expanded memory
asynchronous
Processes move forward at unequal speeds
OS goals and functions
computer system resource manager
Process management: process control, process synchronization, process communication, deadlock handling, processor scheduling, etc.; Memory management: memory allocation and recycling, address mapping, memory protection and sharing, memory expansion; File management: management of file storage space, Directory management, file read and write management, file protection; IO management: buffer management, device allocation, device processing, virtual devices;
The interface between the user and the computer hardware system
command interface
Online control mode (interactive command interface)
Similar to cmd command window
Offline control mode (batch command interface)
Daily programming
Program interface (generalized instructions)
Such as GUI
Realized the expansion of computer resources
1.2 Development of OS
manual stage
The user monopolizes the entire machine, resulting in low resource utilization and insufficient CPU utilization;
Single lane batch processing system
In order to solve the contradiction between man and machine and the mismatch in the speed of CPU and IO equipment; Features: automatic (a batch of jobs can be run automatically one by one without human intervention under normal circumstances), sequential execution, single-channel (program completion or occurrence Switch to the successor program only when an exception occurs); Disadvantage: Only one job is stored in the memory at a time. When an IO request occurs, you need to wait for low-speed IO.
multi-pass batch processing
In order to further improve resource utilization and system throughput, multiprogramming technology was introduced; Features: multi-channel, macro-parallel, micro-serial; Advantages: high resource utilization, large system throughput; Disadvantages: long user response time, no human-computer interaction function (users do not know the running status of their own programs and cannot control the computer) ); Problems need to be solved: how to allocate processors, memory allocation issues for multi-programs, how to allocate IO, how to organize and store large amounts of programs and data while ensuring security and consistency;
time-sharing operating system
Using time slice method, human-computer interaction is possible; Simultaneity: Multiple users use the same computer; Interactivity: Users directly control the program running through the terminal through human-computer dialogue; Independence: Multiple users in the system can operate independently of each other Carry out operations without interfering with each other; timeliness: user requests can be responded to in a short time;
real-time operating system
In some applications, the system needs to be able to process external information within a specified time (shorter than the time slice) (such as aircraft booking systems or missile guidance systems). Therefore, real-time operating systems emerge as the times require. Features: timely and reliable; Category: hard/soft real-time system
network operating system
Sharing of various resources in the network and communication between computers
Distributed operating system
The essential difference between a distributed OS and a network OS is that several computers in a distributed operating system collaborate with each other to complete the same task. Features: Distribution, parallelism
Personal computer
1.3 OS operating environment
Executing a program means that the CPU performs specific operations one by one according to instructions. The CPU executes two programs of different nature: one is the operating system kernel program; the other is the user-programmed program (i.e., the application program on the outer layer of the system, or simply "application program"). For the operating system, these two programs have different functions. The former is the manager of the latter. Therefore, the "management program" (i.e., the kernel program) has to execute some privileged instructions, while the "managed program" (i.e., the user-programmed program) ) These instructions cannot be executed for security reasons. In terms of specific implementation, the operating mode of the CPU is divided into user mode (eye mode) and core mode (also known as pipe mode and kernel mode). The kernel is the underlying software configured on the computer. It manages various resources of the system and can be regarded as a bridge connecting applications and hardware.
CPU status
Classification
User mode, the instruction to switch to user mode is also a privileged instruction;
core state
User mode->Core mode
interrupt
abnormal
Access control instructions
operating system kernel
clock management
Timing
Process switching (time slice rotation scheduling)
Interrupt mechanism
primitive
Such as device driver control, CPU switching
Data structure and processing in the system
Process management
memory management
Device management
Interrupts and Exceptions
system call
Device management
File management
process control
process communication
Memory management
1.4 Architecture
Big core architecture
microkernel architecture
1.5 OS boot and virtual machine