1, computer definition: an electronic computer is an information processing (electronic) machine, which can automatically store, transmit and process information at high speed and accurately.
2. Four stages of computer development (according to the electronic components that make up the computer): electron tube computer, transistor computer, integrated circuit computer and VLSI electronics.
3, computer classification:
High-performance computer: refers to computers with higher performance than microcomputers and workstations, mainly based on computer speed.
Microcomputer: Also known as personal computer (PC).
Embedded computer (system): the microcomputer or the core components of the microcomputer are installed in special equipment to control and manage the equipment, so that the equipment has the characteristics of intelligent operation.
4. Computer applications: scientific calculation, data processing, auxiliary engineering, remote control and artificial intelligence.
5. Emerging computers in the future: superconducting computers, quantum computers, photonic computers, biological computers and neural networks will be combined with computers.
6. Composition of computer system: A complete computer system consists of hardware system and software system.
7. Hardware system: refers to tangible things that make up a computer, such as physical entities and equipment such as components, circuit boards and spare parts, which are called computer hardware; Hardware system is the general name of all physical devices that make up a computer system, and it is the physical foundation of a computer system, also known as bare metal.
8. Hardware system: It includes five parts: arithmetic unit, controller, memory and input/output devices.
Arithmetic unit: Its main function is to perform various operations (arithmetic operation and logical operation) on data.
Controller: The main function is to coordinate and control all components of the computer system to perform the specified work according to the instruction sequence arranged in the program, so that the whole computer system can work in an orderly manner.
Memory: used to store programs, data involved in operations and operation results, and can automatically access programs or data at high speed during computer operation; There are two kinds of memory operations: read operation and write operation.
Basic terms and concepts related to storage:
Memory is usually divided into internal memory and auxiliary memory. Memory is used to store data and instructions to be processed by CPU. External memory is mainly used for long-term storage of programs or data information.
Advantages and disadvantages of internal memory and external memory: The internal memory is composed of semiconductor devices, which has high working speed but high cost, and most internal memory information will be lost after power failure; External memory records information by magnetic substances or concave and convex points, so it will not lose information because of power failure. Its cost is lower than that of the same capacity memory, but its working speed is slower.
Bit (b): A binary bit in a computer.
Byte (b): Eight binary bits (eight bits) are called a byte.
Capacity: refers to the number of binary digits that can be stored in the memory, usually represented by B (progressive rate of common computer capacity: 1024).
Word length: the number of bits of binary data that CPU can process at a time in unit time.
Address: Computer memory is divided into storage units to manage, each unit contains several binary bits, and each storage unit has a unique number, which is called the address of the storage unit.
Input device: transmit external information to the host computer and make it into a form that can be recognized by the machine.
Output device: the function is to turn the result of computer processing into a form that people know.
9. Software: refers to the sum of programs running on a computer and the documents used and maintained by them.
Software system: it is the sum of all kinds of programs, data and documents compiled for running, managing and maintaining computers.
10. Classification of computer software: system software and application software.
System software (required): operating system (Windows series, DOS, Mac OS, UNIX, Linux, OS/2), database system, language processor (C/VB/Java) and diagnostic program.
Operating system: It is the most basic system software and a set of programs for managing and controlling all the software and hardware resources in the computer. (Function) The operating system runs directly on bare metal, which is the first expansion of computer hardware system. With the support of the operating system, computers can run other software.
From the user's point of view, the hardware system and the operating system constitute a virtual machine, which provides a convenient and good platform for users. Operating system is the interface between computer hardware system and other software, and also the interface between computer and users.
Application software (optional): special programs (Photoshop, AutoCAD) developed by users to solve practical problems.
1 1, computer working principle (the stored program is von Neumann principle (1946)).
The computer system consists of five parts.
Instructions and data are stored in the memory, and the computer can automatically take out instructions from the memory and execute them at high speed when working; Represent data and instructions in binary form.
Instruction: specifies a series of basic operations to be performed by the computer.
Program: It is an ordered set of all instructions to complete the processing function.
12, the basic process of computer work: take instructions, analyze instructions, execute instructions, and repeat them in turn until all instructions are completed.
13, the computer uses binary:
Binary has only two states: 0 and 1, which exactly correspond to the two states of physical components.
Binary 0 and 1 can correspond to "true" and "false" in logic algebra, which is convenient for applying logic algebra theory to study computer theory.
14, carry counting: according to the carry principle, the abbreviation is a number system.
15, conversion between decimal and binary, octal and hexadecimal.
16. Data: refers to all symbols that can be input into the computer and recognized, stored and processed by the computer. Data is divided into numerical data and non-numerical data.
17, ASCII: American standard code for information interchange.