First, the composition and functions of the computer
Briefly, into the computer hardware system operator , controller, memory and input / output devices , the five equipment with the operating system software, application composition
The core of one of the computers (central processor) CPU, including operator. Register, a controller, a main function, the process instruction, operation, calculation processing of mass
Memory, memory (Memory), also known as a memory , which is a role of temporarily storing the operation data in the CPU, and a hard disk and other external storage data exchange
Board: I / O devices. Providing a series of physical connectivity for the processor , graphics card, sound card, a hard disk, memory , and other equipment outside the engagement device
Input devices: keyboard, mouse, for sending instructions to the cpu
Output apparatus: After such a display instruction to the display feedback process cpu
Software system: the operating system, applications, system components
OS (operation system) is common unix Linux window system
Unix: is a powerful multi-user, multi-tasking operating system , supports a variety of processor architectures , according to the classification of the operating system, are time-sharing operating system originally developed by KenThompsonDennis
Ritchie and Douglas McIlroy in 1969 at AT & T 's Bell Labs developed
Linux is a free to use and free dissemination of Unix-like operating system , is based on POSIX and UNIX multi-user, multi-tasking , support for multi-threading and multi- CPU operating system. It can transport
The main line of UNIX tools, applications, and network protocols. It supports 32-bit and 64-bit hardware. Linux has inherited Unix to network design as the core, is a stable performance in multi-user
Network operating system, for the company, enterprise server system
windows: Microsoft Windows operating system is the United States , Microsoft developed an operating system uses a graphical drawing interface, user-friendly, multi-user support for multi-tasking and poor security is not good.
Suitable for individual and home users
Applications: such as WPS microsoft office, operating system platform based on different operating systems have different interfaces ABI (application binary interface) different systems application software can not be mixed
Two, linux kernel function and role
linux linux kernel as part of the operating system, the next, to manage all of the hardware hardware device drivers for the library and provides interfaces for applications within the operating system, the core function is to manage hardware devices
Preparation, application to use.
three. The difference between the different linux distributions common release
1, DebianLinux is one of the earliest releases. 1993 August 16 release, debian deb package using the systems management applications library. The user can download and install
2, Ubantu Ubantu debian based distro same deb package system, but not all of the debian package can be installed on ubantu, ubantu biggest highlight is its graphical user-friendly, open source linux-based free desktop operating system, is very popular with users welcome
3, rhel full name red hat enterprise Linux is the oldest distro, has a very personal version of the Enterprise Edition, Enterprise Edition charge Personal Edition is free but its function may be weaker than the Enterprise Edition. Rpm package for use with the different package debian based deb
4, centos Community Edition linux we can understand the free version of rhel. Very similar functions and libraries. Best Personal extremely suitable experimental study linux system
Fast, stable and powerful operating system 5.fedora the Japanese release poor layout applications for users is a powerful, fast free operating system update for redhat rhel company is beta. After testing fedora stable release will be added rehl
Fourth, the common open source license
As we all know, linux is a free operating system, the open source kernel can be compiled for all kernel and package can be published together with the new linux distribution, but the new release will be linux
Impact of open source license
Common open source licenses have BSD Apache GPL LGPL MIT
BSD: lawlessness agreement if re-released product contains the source code, you must have the original BSD license code in the source code. If we publish only a binary library / software, you need to include the original BSD license code in the document libraries and copyright notices / software. Do not promote the use of market revenue code / agency name and the name of the original product
Apache: less affected by the agreement need to use the code to the user's copy of Apache Licence If you modify the code, need to be modified in the file description. Extending the code
(Modified code and the source code derived) with a required protocol, trademarks, patent notice original code and a predetermined additional instructions need to include the original OF. If the re-release of the product package
Notice containing a file, the file needs to have in the Notice Apache Licence. You can add your own license in the Notice, but not the performance for the Apache Licence constitute a change
The starting point of the GPL code is open source / free use and reference / modification / derivative code open source / free, but not allowed to modify the code and derived as a closed-source commercial software release GPL Yan
Grid requires the use of a GPL library of software products must use the GPL, GPL agreement for the use of open source, commercial software or confidentiality requirements of the code department is not suitable for integration / mining
Use as a basis for the development of libraries and secondary
MIT and BSD license is as wide range of authors want to retain the copyright, without any other restrictions. In other words, you must include a statement of the original license agreement in your distro, no matter you are
Binary distribution or as source code released.
LGPL allow commercial software library reference (link) mode without using the open source code library LGPL commercial software. This makes use of the LGPL open source code can be used for commercial software
As a reference library and publish and sell
Five, Linux philosophy
And different windows, everything is a file, hardware information, network information in linux. Login information, all stored as files in the directory, bringing together under / (root directory),
Six. Linux directory structure characteristics and directory naming convention
All directory on a Linux logical only vertex / (root), that is the starting point of all directories.
All Linux directory structure of a tree is a hierarchy upside down.
The directory structure and the partition device is okay, that is different directories across different disk devices or partitions.
All directories are in accordance with certain categories of regular organization and named.
Linux level directory overview
1.
2. .
3. ├── bin # binary commands commonly used directory (ls, mkdir, etc.)
4. ├── boot #Linux desired kernel boot file and directory
5. ├── dev # device file directory (sound card, disk, etc. ')
6. ├── etc # binary packages (yum, rpm) of the default configuration file path, directory service startup command stored (/etc/init.d(yum,rpm))
7. ├── home # ordinary user's home directory
8. ├── lib # library file storage directory
9. ├── lib64 # library files stored in a directory (32-bit systems do not have this directory)
10. ├── lost + found # boot time in this directory check and repair system crash or accidental shutdown resulting file fragmentation
After 11. ├── media # Plug and Play device mount point is automatically stored in this directory as U disk, cdrom / dvd automatically mounted, will in this directory.
12. ├── mnt # mount directory is generally used to temporarily mount the device, such as a u-like, first mount can use
13. ├── opt # directory is generally used to install the software
When 14. ├── proc # operation, process information and kernel information (cpu, hard drives, memory information, etc.) stored in here
15. ├── root # super user root's home directory permissions
16. ├── sbin # mostly stored in the system management commands, is super user permissions root storage directory of executable commands
17. ├── srv # store some data to be extracted after the server is started.
18. ├── sys # for the device into hierarchies in the system, and provide detailed information about the user data structure kernel mode programs
19. ├── tmp # will produce a temporary file when the user runs the program, it is stored in this directory
20. ├── usr # system directory to store the program. Such as command, help files, etc.
21. └── var # This directory contents change frequently