Among the many characteristics of computers, the most important ones are:

Information is indestructible. Information is not like objects and energy, matter is indestructible, energy is also indestructible, its form can be transformed, but the indestructibility of information is different from theirs. A cup is broken, and the atoms and molecules of the ceramics that make up the cup have not changed, but they no longer become a cup.

Another example is energy, we can turn electrical energy into heat energy, but after turning it into heat energy, the electrical energy is gone. The indestructibility of information means that after a piece of information is generated, its carrier can be changed and can be destroyed, such as a book or a CD, but the information itself has not been destroyed, so the indestructibility of information is a great feature of information.

Information can be reproduced cheaply and can be widely disseminated. The reproduction of information is not like the reproduction of objects, and the cost of copying a piece of information into 1 million pieces of information is very low. Although the creation of information may require a large investment, replication requires only the cost of the carrier, and can be replicated in large quantities and widely disseminated.

The value of certain information is very time-sensitive. A piece of information is very valuable at one point, but after that point, it may have no value at all. Financial information can be very valuable when it needs to be known, but after that moment, it will be worthless.

Another example is information in wartime, the information of the enemy has a very important value at a certain moment, which can determine the victory or defeat of a war or campaign, but after this moment, this information becomes useless. Therefore, a considerable part of the information is very time-sensitive.

Stored programs and automatic controls.

The reason why computers have strong vitality and can develop rapidly is because computers themselves have many special points. The main ones are fast, big, long, refined, intelligent, self-sufficient, and wide. Specifically, it is reflected in the following aspects:

1) Fast processing speed. The speed of a computer's fast processing is one of the important indicators of a computer's performance, and it is also a major performance indicator for her.

2) Large storage capacity and long storage time. With the widespread use of computers, more and more information is stored in computers, and the storage time is getting longer and longer. Therefore, computers are required to have massive storage, and the information is kept for years to decades, or even longer.

3) High calculation accuracy. The computer can guarantee the arbitrary accuracy requirements of the calculation results.

4) Logical judgment ability. Computers can not only perform arithmetic operations, but also perform various logical operations, and have the ability to make logical judgments.

5) Ability to automate work. As long as the necessary elements such as processing requirements, processing steps, and processing objects are stored in the computer system in advance, the computer can automatically complete all the predetermined processing tasks without human participation after starting the work.

6) Wide range of applications. So far, almost all fields involved in human beings have applied computers to varying degrees, and have played their due role and produced their due effects.

This section explains the second lesson in the computer knowledge popularization and application class: the characteristics and applications of computers.

Among the many characteristics of computers, the most important feature is the ability to quickly partner with computers. Computers have the following characteristics:

1. Fast computing power.

The work of an electronic computer is based on the principle of an electronic pulse circuit, which consists of electronic circuits that constitute its various functional components, in which the propagation of electric fields plays a major role.

We know that electromagnetic fields travel very fast, and today's high-performance computers can perform tens of billions of additions per second. If a person can do an operation in one second, then the average computer has to do more than 100 years of work in one hour.

2. Sufficiently high calculation accuracy.

The calculation accuracy of the electronic computer is not limited in theory, and the general computer can reach 15 significant digits, and any accuracy requirements can be achieved through certain technical means.

There is a famous mathematician in history, who once took 15 years to calculate pi to the 707th place. Now if you leave this to a computer, you can count 100,000 bits in a few hours.

3. Super memory ability.

There are many storage units in a computer that are used to memorize information. Internal memory is an important differentiator between computers and other computing tools. Because of the ability to memorize information internally, it is possible to retrieve data from the outside every time during the computation.

However, by simply inputting the data into the internal storage unit in advance, the data can be obtained directly from the storage unit during the calculation, which greatly improves the calculation speed. The capacity of a computer's memory can be made very large, and it has a particularly strong memory.

4. Complex logical judgment ability.

People have the ability to think. Thinking ability is essentially a logical judgment ability, which can also be said to be the ability to analyze cause and effect. With the help of logical operations, the computer can make logical judgments, analyze whether the proposition is true, and make corresponding countermeasures according to whether the proposition is true or not.

5. The ability to work automatically according to the program.

The general machine is controlled by a person, and the person gives the machine a command, and the machine is finished and becomes an operation. The operation of the computer is also controlled by humans, but because the computer has internal storage capabilities, instructions can be entered into the computer in advance for storage.

After the computer starts to work, the instructions are taken from the storage unit in turn to control the operation of the computer, so that people can realize the automation of the operation without interfering with the work of the computer. This way of working is called program control.

Answer]: BA item, before the merger, the computer host has a liquid clear motherboard, CPU, memory, hard disk, and may also have a graphics card, sound card, network card, etc.; c, the computer can work without disks; D, the letters on the keyboard are sorted by how often the buried photo is used.

Answers]: a, c, d

The host of the computer includes the CPU and memory. Some special notebooks do not have a large amount of computer data or do not need to block macros to store data, so they can operate at a high level without a hard disk. The arrangement of the letter keys on a computer keyboard is not random, but has a certain pattern.

Answer] :d computer has the characteristics of fast computing speed and high accuracy, and Yu Huai also has the ability to remember and make logical judgments. The computer operation process can be carried out continuously by self-alignment, without the need for manual intervention.

1.(1) Automatic control capability.

2) Fast processing speed.

3)"Memory"Competent.

4) Be able to make logical judgments.

5) High calculation accuracy.

6) Support human-computer interaction.

7) Strong versatility.

2.A computer virus is a kind of artificially created program that destroys computer information or systems during computer operation. This kind of program does not exist independently, it is hidden in other executable programs, and it is both destructive, contagious and latent.

It will affect the running speed of the machine and make the machine unable to operate normally; At worst, the machine is paralyzed, which will bring immeasurable losses to users. This destructive program is often referred to as a computer virus.

1 Characteristics of computer viruses.

Computer viruses have the following characteristics:

1) Parasitism.

2) Contagious.

3) Latentity.

4) Concealment.