Basic Knowledge Notes

Computer Resources

An operator: A component that implements arithmetic and logic operations.

Controller: The command system of the computer. The controller accesses the memory through the address, takes out the instruction from the memory, after the analysis by the decoder, produces the corresponding operation control signal according to the instruction analysis result to act on the other components, causes each component to coordinate the work methodically under the controller control.

Memory: is a memory component used to store all data and programs in a computer, and its basic function is to store (write) or fetch (read) information at a specified address. such as registers, memory, hard disk, CD-ROM and other memory consists of a number of storage units, each storage unit has an address, the computer through the address of the memory unit read and write. Can think about why the hardware and operating system of the general maximum recognizable memory is 4GB ? What is the maximum memory size for the max bit?

Input device: is a device that enters information (Programs, data, sounds, text, graphics, images, and so on) into your computer. Common input devices are: keyboard, mouse, graphics scanner, touch screen, barcode input, light pen and so on. External memory is also an input device.

Output device: Mainly display, printer and plotter. External memory is also an output device

The operators and controllers are collectively referred to as central processing (processing Unit).

The arithmetic calculator first calls the data Order register (the speed is very quickly divided into 1-2-3 cache speed gradually reduced, the capacity is small integrated in the CPU cost is very high) → memory (high speed, capacity, cost moderate) → hard disk (slow, large capacity cost low), HDD is divided into traditional mechanical hard disk (speed is a measure of speed) and SSD solid-state Drive

It is conceivable that the CPU must read data from the register the fastest, second memory, the slowest is the hard disk. So the register and memory have to have a predictive mechanism, to be able to pre-cache a portion of the data inside them, speed up the CPU to read data.

Computer resources are nothing more than CPU and memory, software is good or bad is the utilization of these resources.

CPU classification

Streamlined instruction set RISC

The English name of RISC is reduced instruction set computer, Chinese is a simplified instruction set computer

Represents the product:IBM Power CPU, ARM;

Complex instruction Set

CISC (Complex instruction Set computer) complex instruction computer

Representative Products: X86 x86_64 Intel and AMD

Kernel (Kernel) features:

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M01/5B/2F/wKiom1UBKiTDq9qXAAEdaXBgW1U601.jpg "title=" 185952980.jpg "alt=" Wkiom1ubkitdq9qxaaedaxbgw1u601.jpg "/>

Process management (running programs)

Memory Management (

File system

Network functions

Hardware Drivers

Security mechanisms

It's complicated, and it's a little hard to understand.

The most intuitive of the system invocation interface is the shell that we operate the

There are two main types of shells:

One: Graphical interface shell (graphical User Interface shell is GUI shell)

For example: The most widely used Windows Explorer (Microsoft's Windows family operating system) and also includes the well-known Linux shell, where the Linux shell includes X window Manger (Blackbox and Fluxbox) , as well as more powerful CDE, GNOME, KDE, XFCE.

II: Command-line shell (CLI shell, Interface shell)

For example:

BASH/SH/KSH/CSH (Unix/linux System)

(MS-DOS system)

cmd.exe/Command Prompt character (Windows NT system)

Basic principles of Linux:

All documents (including hardware)

Consists of small programs from multiple single purpose

Combine small programs to complete complex tasks

Avoid capturing user interfaces as much as possible, in order to facilitate scripting to automate implementation;

Use a text file to save the program's configuration data: A text editor can be used to complete the system and service configuration work;

File systems for Linux:

Linux Strictly distinguishes character case

Hierarchical structure representing file paths

The Inverted tree

A directory: is a namespace

Relative path: From the non-top, the default path when starting from the current path

Absolute path: The path from the top-level namespace start tag

650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M00/5B/2F/wKiom1UBKBCB4LllAAFHA0ZnMsU591.jpg "title=" 67044524gx6dgqynyvy88&690.jpg "alt=" Wkiom1ubkbcb4lllaafha0znmsu591.jpg "/>

Linux is a single directory, the partition is hanging on to these directory nodes (it can be understood that the partition and directory is bound, open this directory is to enter this partition).

Windows partitions are parallel to the directory, and a partition is a root.

Users of Linux

Linux is a multi-user multitasking operating system, with administrator account root and only one.

The user is known as a group, the same strictly case-sensitive, also stored in the form of files, without the cumbersome registry 650) this.width=650; "src=" Http://img.baidu.com/hi/jx2/j_0003.gif "alt= "J_0003.gif"/>

Linux since all the data are stored in the form of files, but also a multi-user multi-tasking operating system. What can you think of???? The attribution of a document; a professional point called a file's permission

1175041 Dr-xr-x---.    Root root 4.0K Mar 11 23:14. itself directory

2 dr-xr-xr-x.   Root root 4.0K Mar 10 22:59. Represents the parent directory

1186702 Drwxr-xr-x. 4 root root 4.0K Jan 1 04:41. config file preceded by dots indicates hidden files

The file permission belongs to the main genus Group

Basic Knowledge Notes