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Summary of Knowledge Points for Computer Secondary Multiple Choice Questions
I. Overview
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The world's recognized first computer was born in the 1940s.
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According to the traditional generation method of electronic computers, the first to fourth generation computers are
electronic computers, transistor computers, small and medium-scale integrated circuit computers, and large-scale and ultra-large-scale integrated circuit computers. -
CAD - Computer Aided Design
CAM - Computer Aided Education
CIMS - Computer Integrated Management System
CAI - Computer Aided Manufacturing
2. Representation and storage of information
1. Data: Symbolic representations of facts, situations, concepts, and instructions processed by human or automated means.
For example: characters, tables, images
2. Information: It is a reflection of the attributes of objective things, and it is a data representation that has been processed and has an impact on human objective behavior.
3. The data unit in the computer
The smallest unit of data is a bit, and the basic unit of storage capacity is a byte.
Bit: The code is only 0 and 1, using multiple numbers to represent a number, each of which represents 1 bit.
Byte (bit): A byte consists of 8-bit binary numbers.
Note: A byte can represent a data, or an English letter or other special characters, and a byte is composed of 8-bit binary numbers.
4. Computer hardware system
The computer is composed of 5 parts including input device , memory , arithmetic unit , controller and output device .
1. Calculator
The arithmetic unit is a processing plant for computers to process data to form information, and mainly perform arithmetic and logic operations on data.
The performance index of the arithmetic unit:
word length and operation speed.
2. Controller
The controller is composed of four parts: instruction register, instruction decoder, operation controller and program counter.
Machine instruction: It is a binary code string composed according to a certain format, which is used to describe the basic operations that a computer can understand and execute. '
The composition of a machine instruction: opcode, operand.
CPU (Central Processing Unit): including calculator and controller.
3. Memory
According to the purpose, memory is divided into main memory (internal memory) and auxiliary memory (external memory).
(1) memory
Memory: Read Only Memory, Random Access Memory, Cache.
a. Read-only memory (ROM)
Store fixed programs and data.
Stored in when manufactured, stored permanently, can only be read but not written, and will not be lost when the power is turned off.
b. Random access memory (RAM)
Microcomputer memory.
Data can be read, data can be written, data lost when power off, capacity 2~16GB.
c. Cache
Store frequently accessed data.
(2) external storage
Including hard drives, solid state drives, CDs, and removable external storage.
a.hard disk
It is composed of a disk, a read-write control circuit and a drive mechanism.
1. Computer operating system
2. Various applications
3. Data files
b. SSD
Solid-state electronic memory chip arrays have a wide operating temperature range, much higher read and write speeds than hard disks, and higher costs.
c. CD
A disk that reads information optically has
large storage capacity, high reliability, long life, fast reading speed, low price, and is easy to carry.
4. Input device
keyboard, mouse, camera, etc.
5. Output device
Monitors, printers, speakers, etc.