1, description of the structure and functions of the computer.
Computer systems consist of hardware (Hardware) systems and software (Software) system composed of two major components, the system is based on modern PC hardware design and production of von Neumann architecture, Von Neumann computers made in 1946, consists of five major components , they are: the operator, controller, memory (including a main memory and an external memory), input and output devices.
The input device requires the delivery of programs and data to the computer; memory for storing programs and data, and an operation result of the intermediate and final results; operator to input various data arithmetic logic operation; and a controller coordinating the various components work machine ; output device the result of the processing to the user.
FIG five units are connected as follows:
2, the kernel function and effect described
Core function is to process management system, memory, device drivers, and network file systems, is to provide a system call interface for the user space and improve system stability.
3, according to the series listed common Linux distributions and describe connections and differences between the different releases.
The main points debian redhat series and series. The difference between the different releases mainly different package management tools.
RedHat series include: RedHat, CentOS, Fedora
Debian series include: Linux Mint, Ubuntu, Debian GNU / Linux
Other:
Slackware series include: Suse, OpenSuse
Gentoo series
ArchLinux series
4 difference, describing common open source license (GPL, LGPL, BSD, Apache, etc.) as well as open source license
GPL: Public License, its two most notable features are: viral spread and does not allow closed-source commercial release. The so-called sexually transmitted virus that is as long as the GPL and glue relationship must follow the GPL. GPL is a copyright of the source code for the software, rather than compiled binary version of the copyright, so you have the right to free access to software source code, but not the right to free access to the binary version of the software.
LGPL (lesser): It is a major GPL designed for use as a library open source license. The LGPL library as a separate module is referenced commercial software, open commercial software is not required; however, modified or derivatized on this module code must also use the LGPL.
Apache: It is well-known open source protocol used by Apache nonprofit organization. After it allows code changes, as a commercial or open source software re-released, but each modified files must be placed copyright notice.
BSD: It is the abbreviation for Berkeley Software Distribution, a user is given a lot of freedom agreement. Users can freely use, modify the source code and then released as open source or commercial software, but must use the BSD protocol mentioned in the copyright statement, and comes with the BSD license, you can not use the name of the author of the original source code for commercial promotions.
MIT: It is as wide range of protocols and BSD agreement, only the original author retains copyright, but no other restrictions.
5, description of the Linux philosophy, and according to their own understanding of its explanatory description.
Everything is a file:
either command, hardware, software, operating system, processes, etc. relative to the operating system kernel, the file is considered to have their own characteristics or type.
Small, single-purpose program:
program and execute files are not very complicated, so as to ensure the efficient operation of the Linux kernel.
Combination applet complex tasks:
complex tasks by connecting a plurality of simple procedures complex functions of time. At the same time to ensure the efficiency of simple functions, complex procedures must also be efficient.
As far as possible to avoid interaction with the user:
using the command line to perform an excuse for higher efficiency, easy to combine other tools to achieve more functionality.
Save the configuration file using a text message:
No matter what configuration changes are simply modify the configuration file can be, when the configuration file in text format, just any modification to a text editor.
6, description linux directory structure directory structure and naming conventions.
Linux directory structure naming convention
almost all Linux versions will follow FHS (Filesystem Hierarchy Standard), Chinese translation is the filesystem hierarchy standard. C similar to the Windows operating system disk file directory, FHS organize files using a tree structure. FHS defines the purpose of each region of the system, files and directories that constitute the minimum required, but also gives the exception process with the conflict processing.
Linux directory structure
/ boot: the boot file storage directory, kernel file (vmlinuz), the boot loader (bootloader, grub) are stored in this directory
/ bin: basic commands for all the users; can not be associated to a separate partition, boot the OS i.e. the program will use
/ sbin: basic commands management classes; not related to a separate partition, OS will be used to start a program that is
/ lib: when you start the program depends on the basic shared libraries and kernel module files (/ lib / modules)
/ lib64: on x86_64 systems dedicated to assisted shared library file location
/ etc: configuration file directory
/ home / USERNAME: regular user home directory
/ root: administrator home directory
/ media: a portable mobile device mount point
/ mnt: temporary file system mount point
/ dev: device special file storage location and file
b: block device, random access
c: character device, linear access to
/ opt: third-party application installation location of
services running on the system used: / srv data
/ tmp: temporary file storage location
/ usr: Universal Shared, Read-only Data
bin: ensure that the application system with full functionality provided
lib: 32 bit using
lib64: there is only 64-bit system
include: headers C program (header files) share: Structured independently data, e.g. doc, man and other
local: installation location of the third party application
bin, sbin, lib, the lib64, etc, Share
/ var: variable data Files
cache: caching application data directory
lib: application state information data
local: dedicated to the application of variable data stored in / usr / local;
lock: lock files
log: log files and directories
opt: dedicated to the / application data stored in the variable opt;
rUN: running processes related data normally used for storing process pid file
spool: application data pool
tmp: temporary data generated between the two to save the system reboot
/ sys: current output for related information on system hardware virtual file system
/ proc: kernel for output process-related information in the virtual file system
storage location information security enhanced Linux, selinux related security policies: / selinux