Linux informal learning essay (1)

11.5
into linux learn the first thing to find a Chinese input method.
Linux is a free unix-like operating system
GPL: gnu General Public License. Thomas Stowe Manti out gnu project, a protocol software free thought.
Linux was born October 5, 1991.

Linux basic idea:
A) Everything file
b) Each file has identified uses

Linux Features:
A) multi-user, multi-tasking operating system.
b) Most network protocol support, easy remote management.
c) powerful memory management and file system management.
d) a large number of free software and free software. (Mainly server)
E) excellent in stability and safety.

Architecture Linux
users - the application layer --Shell layer - the core layer - hardware
kernel explanation: the establishment of a core platform for communication between computer software and hardware, the kernel provide system services, such as file management, virtual memory, device I / O , process management and so on.
Linux kernel
intermediate layer:
exchanges with the outside world:
(port) 80: http responsible for network communication of apache; 21: FTP file transfer; 22: ssh remote communication.
process table process table
cron timer task
like
bottom: file system
top: terminals and terminal process task reading from the terminal

 11/5
Linux file system using EXT4 format (win usually NTFS)
main files into directories and files based on common file format, if the Linux file system as a tree, all the ordinary file (normal file) are leaf nodes, directory node are all child nodes.
Linux extension of the files is not mandatory, and even can be said without an extension, he said it is best to write extensions but usually when you save the file to facilitate the management, help to understand the contents of the file.

11/6
/: root directory: storage directory is created according to different usage rights.
root: the system administrator's home directory, other users do not have access.
home: the average user's home directory.
bin / sbin ..: executable files, sbin only administrators can perform.
etc: system configuration files directory. ! !
usr: user share resources to store some program or file.
var: storage file system changes frequently (log).
mnt / media: the default mount point of the disc.
boot: Some files used when starting the system.
device file storage systems: dev.
and many more.