Development
Although computer technology has developed rapidly, the principle of stored programs is still the basic operating principle of computers. Since the day the computer was born, this principle has determined the main way people use computers-writing programs and running programs. Scientists have been committed to improving the automation level of program design, improving the user interface, providing various development tools, environments and platforms, all of which are to make people more convenient to use computers, and they can use computers with less programming or even no programming. , Because computer programming is a complicated mental work after all. But no matter how the user's development and use interface evolves, the principle of stored program control has not changed. It is still the basis for us to understand the functions and characteristics of computer systems.
In the mid-1930s, von Neumann boldly proposed abandoning the decimal system and adopting the binary system as the basis of the number system for digital computers. At the same time, he also said that the calculation program is pre-programmed, and then the computer performs the numerical calculation work in accordance with the calculation sequence established by people in advance. Von Neumann and his colleagues designed a complete prototype of a modern computer and determined the five major components and basic working methods of a stored-program computer. This design idea of von Neumann is hailed as a milestone in the history of computer development, marking the real beginning of the computer era. Von Neumann successfully applied his theory to the design of computers. The computer manufactured according to this principle is called a von Neumann structured computer. The world’s first von Neumann-style computer absorbed The EDSAC developed by von Neumann’s Cambridge University in 1949, because of his outstanding contributions to modern computer technology, von Neumann is also known as the "father of computers" and the principle of stored program control is also known as Feng · Neumann principle.
Working principle
First, the program and data are sent to the memory through the input and output devices. General memory is divided into many storage units, each of which has an address number, so that programs and data are stored in a certain order, and the memory is also divided into several areas, such as a special storage area and a special storage area. The data area of the data. Secondly, to execute the program, you must start with the first instruction and execute it one by one afterwards.
Generally, according to the order of storing the address numbers, it will be executed from small to large. When a conditional transfer instruction is encountered, the order of execution will be changed. Each execution of an instruction requires three steps: the first step is to send the instruction from the memory to the decoder, which is called instruction fetching; the second step, the decoder decomposes the instruction into opcodes and operands to generate Corresponding various control signals are sent to various electrical components; the third step is to perform corresponding operations. This process is controlled by the electronic route, so as to realize automatic and continuous work. During operation, the controller takes out the instructions stored in the internal memory in the order of addresses (accessing instructions in the order of addresses), then analyzes the instructions and executes the functions of the instructions. When encountering a transfer instruction, it transfers to the transfer address, and then follows the address order Access instructions.
Theoretical points
The idea of storing programs-describe the calculation process as a program composed of many commands in a certain order, and then enter the program and data into the computer together, and the computer will After the input program and data are processed, the result is output.
The main point of stored program control is: the number system of digital computers is binary; the computer should execute in the order of programs.
The computer constructed according to the stored program control structure must have the following functions:
1. Send the required programs and data to the computer;
2 Must have the ability of long-term memory procedures, data, intermediate results and final calculation results;
3, be able to complete various arithmetic, logical operations and data transmission and other data processing capabilities;
4. The program can be controlled according to needs, and the various parts of the machine can be controlled to coordinate operations according to instructions;
5, the processing results can be output to the user as required.
In order to complete the above-mentioned functions, the computer must have five basic components, including:
1. Input devices for inputting data and programs;
2. Memory Program and data storage;
3, complete data processing arithmetic unit;
4, control program execution controller;
5, output processing The output device of the result.