Dennis * Richican Thomson Unix
10 years, computer became very popular MIT-------mit
Space travel------->c language
Unicorn Ubuntu Xubuntu
First, the system starts
PC Machine: Ubuntu Startup
| Hardware detection|
BIOS self-Test = = " Bootleader
Initializing memory
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Boot program Boot program
| |
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OS Boot Boot kernel
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Application System initialization
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User Login
Do you have any idea about our operating system?
Thinking: What are the system functions of the operating system?
Function: rational management and allocation of resources (Hardware resources: Cpur,ram, other, software resources: process, threads)
(2) Management part of the operating system
1. Memory Management
The paladin----->7,8g stored on our hard drive. Memory 2G.
Virtual Memory: Use a portion of the hard disk as memory.
2. Process Management
Simply put, a process is the process of executing a program once. ----> Time slices.
The time that the CPU is assigned to the program execution.
OS can preempt resources, good real-time performance
Can not preempt resources, real-time poor, to prevent system crashes.
A 32-bit operating system with a process space size of 4G (0-0XFFFFFFFF)
2 of 32 is 4294967296=== "binary
4294967296/1024/1024/1024 = 4G
Kb MBGB
This means that our 32-bit operating system can use 4G of virtual address space.
Think: How is our 4G virtual address space allocated?
3. Network protocol stack
TCP, UDP protocol, etc.
4. Driver
Ii. File System
Equivalent path: Starting from the current directory
Absolute path: From the root directory
Common file devices are available in the following categories:
B: Block device files
C: Character device file
D: Catalog file
-: Normal
L: Soft Link file
P: Pipeline File
S:unix domain socket file (punch for process communication)
Basic commands of Ubuntu system
CD: Switch directories
Example: Cd/home/ubuntu
LS: View the contents of a directory or file attributes
(1) LS
Show current directory Contents
(2) Ls-l
Displays the file information in the current directory
-rw-rw-r--1 ubuntu ubuntu Oct 01:34 One
Part I: File types
B: Block device files
C: Character device file
D: Catalog file
-: Normal
L: Soft Link file
P: Pipeline File
S:unix domain socket file (punch for process communication)
Second part: Permissions (file owner + file owner Group + other users)
R Read, W write, X Execute
4 2 1
100 010 001
R---W--x
In octal ID: 0775
RWX rwx R-x
Part III: Number of hard links
Part IV: File owner name
Part V: Files belonging to the group
Part VI: Size of the file (default unit byte)
Part VII: Time when the file was last modified
Part VIII: File name
Recursive display of all subdirectories, ls-r
Show all files, including hidden files, ls-a
LS-LH-Band unit display file size
PWD: Displays the absolute path of the current directory
Management commands for Ubuntu packages
DPKG Package Management
Features: Download Local installation package, does not detect dependencies between packages
1. Supported Package formats
A.DEB Package Format
Deian, Ubuntu
B.RPM Package Format
RedHat
Naming conventions: for example Sl_3.03-16_i386.deb
Software Name: SL
Version number: 3.03
Fixed version number: 16
Available platforms: i386, available for the Intel x86 platform
Deb: Package Type
A. Install the Software
sudo dpkg-i Package
Or
sudo dpkg-i *.deb
B. Uninstalling the Software
sudo dpkg-r package name
2. Apt-get Package Manager
Characteristics:
(1) Support Online installation
(2) Check the package dependencies
A. Install the Software
sudo apt-get instll package name
B. Uninstalling the Software
sudo apt-get Remove package name
C. Update the index file
sudo apt-ge update
Note: A few important paths
/var/cache/apt/archive---> Downloaded packages
/etc/apt/sources.list----> Mirror Site server address
/var/lib/apt/lists----> Index file for each Jingxi County site
Learn Linux Miscellaneous
