In computer knowledge base, for some non-majors in college students is concerned, it has been a pain in their hearts, and for technical education students, many students after work, is also aware of shortcomings and lack the knowledge of their own, want to go back Bubu basics. Many courses on computer-based content complicated, but whether it is books or university courses, are a bit out of work. In particular, numerous and basic computer knowledge and want to learn from zero or review are time-consuming.
In view of this, this series of articles will take you faster to make up the necessary basic knowledge of programming, covering the three basic computer knowledge areas: Principles of Computer, operating systems, computer networks, select the article that the most part as a programmer should master knowledge, its essence, abandoned in that part of the programmer unimportant.
The purpose is to:
- Help you form a computer architecture knowledge
- Help you understand the underlying principles of computer
- Help you learn where the practical work of outstanding design
Benpian is the structure of the computer system and the principle of the computer.
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Von Neumann architecture
Von Neumann architecture, one sentence is: Computer Design Concept structure stored program instructions and data together.
When studying the history of the computer in the front, we know that early computer program can only run the utility, and how to understand? For example: There is a computer program which can only run the math, then it can not run word processing software, nor could get to play the game, if you want to allow it to carry out other functions, we need to change the program of the computer, in that time, the so-called rewriting program now does not mean re-compiling a program so simple, but you must change the circuit or change the structure, and even redesign the machine.
This is very pit father ah. If the computer can only be used to play games, can not be used to write code, or that can only be used to write code that can not be used to play games, then we will not be able to play for a game for a while to write code, like this is very unreasonable. So von Neumann was thinking the program is stored up, and then in the design of the underlying hardware of the time, is no longer a proprietary circuit design, but rather a general circuit design, when we need to run a program, we first this program translated into the language circuits can understand, then let to perform general-purpose circuits associated with logic.
This is the core concept of the von Neumann architecture - stored program instructions, general circuit design.
Understand how von Neumann architecture is born, if we can understand the dramatic changes Von Neumann architecture to bring the computer field, we can understand why the von Neumann architecture so important. Stored by the computer of the concept extends von Neumann architecture, before changing all bad, chosen to create a common instruction set architecture, and converted to a series of program instructions to run a so-called operation, the entire computer more flexible. By means of a particular type of instruction as calculation data, a memory type computer program which can easily be changed, and under program control, change the contents of operation, the time change without redesigning circuit, no reshaping structure of the computer, this is the von Neumann architecture of the enormous contribution.
Directed by von Neumann architecture complete computer contains five components:
- Memory: used to store programs and data
- The controller: to control the input flow to run the program and data, and the result of the processing operation
- Operator: main operating arithmetic and logic operations, and temporarily storing the intermediate result to the computing unit
- Input device: used to convert information in the form of the familiar type information can be recognized by the machine, common with a keyboard, a mouse, etc.
- An output device: the machine may convert the operation result information familiar form, such as a printer output, monitor output, etc.
We use all modern computers, in essence, are von Neumann machines, including laptops, desktops, ordinary servers, mini-computers and so on. By the von Neumann architecture that guides you through the computer, you must have the following several functions:
- And be able to program desired data to a computer (done by the input device)
- Long-term memory can be program, data, intermediate results and the final result of the operation capacity (completed by the memory)
- Ability to have an arithmetic, logical and data processing and data transfer processing (controller completed by the operator)
- Processing results can be output to the user as requested (performed by the output device)
Von Neumann architecture diagram:
We can see that the CPU and memory are separate, which leads to a problem: the problem between the CPU and memory rate can not be reconciled. Since the CPU is a high speed operation, the processing rate is very fast, but no CPU fast memory, the CPU of the data transmission speed, which often causes the CPU idle waiting for data transmission, this way is very wasteful of resources.
Since we all know that the performance bottlenecks exist von Neumann architecture, then, how to solve it?
Structure of modern computers
Modern computer has been modified in the structural basis of von Neumann architecture, the performance differences to solve the problems between the CPU and storage devices. Below is a diagram showing the structure of a modern computer:
It can be seen that, with the front is not the same, the arithmetic unit, a controller, and a memory composed of a modern computer CPU.
Memory, broadly, may be understood as a medium for storing data, including tape and a hard disk. However, this mainly refers to the memory device around the high-speed CPU, including registers and memory. Structure of modern computers, the memory can be understood as the core structure.
About memory, there are a lot of knowledge required to understand, we will introduce in detail in a future article.
to sum up
In this section, we need to understand the meaning and how it is produced by von Neumann architecture, but also need to understand the structure and characteristics of modern computer and it solves the problem.
