[1.4.1] Von Neumann structure
Basic point of stored program principle: instruction driven
The programs are stored in the memory of the computer, and once the computer is started, it can execute them in the logical order specified by the program, automatically completing the processing described by the program
Pay attention to the direction of the data flow
- The characteristics of
- With the arithmetic unit as the center, centralized control.
- In memory, instructions and data are treated equally
- Memory is a one-dimensional structure accessed by address and linearly addressed sequentially, with a fixed number of bits per unit
- Instructions are executed sequentially
- An instruction consists of an opcode and an address code
- Instructions and data are expressed in binary code, using binary operation
Improvements to the system architecture
- Improvements in input/output mode
- Parallel processing
- Memory organizational structure development
- Instruction set development
[1.4.2] The influence of software on system architecture
When software is not stricter, it means that software can be moved from one machine to another with little or no modifications, so that the same software can be used in different environments.
== The technology of software transplantation is as follows: ==
Unified High Level Language
It is difficult in the near term but still one of the important problems that must be solved in the long term
how
- Serial machine: a series of computer systems having the same system structure but differing in composition and implementation techniques
Simulation and Simulation
- Simulation and simulation: from the point of view of the instruction system, refers to the realization of the instruction system of one machine on the system structure of another machine
- Simulation: using machine language programs to explain the implementation of software porting methods
- Emulation: A method of using a microprogram to directly interpret another machine instruction
simulation
A Machine for simulating work is called Host Machine; The simulated B Machine is called a Virtual Machine.
All the interpreters written for various kinds of simulation are generally called simulation programs, which are very complex and time-consuming to write and are only suitable for porting software with short running time, few times of use, and no constraints and restrictions on the time relationship
The simulation
Machine A for simulation is called the host Machine, and Machine B for simulation is called the Target Machine.
All interpretative microprograms written for simulation are generally called simulation microprograms;
The choice between the two
[1.4.3] Development of parallelism
The concept of parallelism
- parallelismParallelism The performance of multiple operations or operations by a computer system at the same time or at the same time intervals
- Simultaneity: Two or more events taking place at the same time
- Concurrency: Two or more events occur at the same time interval
- The purpose is to improve the efficiency of the computer by parallel processing
Technical approaches to improve parallelism
- Time overlap: The introduction of a time factor that allows multiple processes to stagger each other in time, overlapping each part of the same set of hardware in turn, in order to speed up hardware turnover and gain speed
- Resource duplication: The introduction of space factors, to win by quantity. The performance of computer system can be greatly improved by repeatedly setting hardware resources
- Resource sharing: A software approach that allows multiple tasks to take turns using the same hardware in a chronological order
A single processor
In the process of developing high-performance single-processor, the leading role is the principle of time overlap (the specialization of component functions) and the application of the principle of resource duplication (essentially, the function of multiprocessor is simulated and the concept of virtual machine is formed).
multiprocessor
The multi-machine system follows the principle of time overlap, resource duplication and resource sharing, and develops into three different multiprocessors: heterogeneous multiprocessor, homogeneous multiprocessor and distributed system
Coupling degree: reflects the closeness of the physical connection between the machines in a multi-machine system and the strength of the interaction ability