The classification of computer network, like the general classification method of things, can be classified according to the different properties of things, that is, the attributes of things. The following is a summary of the knowledge points of computer level that I have compiled. Welcome to refer to it!
History of Computer Development: The first computer, ENIAC, was manufactured in the University of Pennsylvania from 65438 to 0946. Computers have been developed for four generations, and the components used are: electron tubes, transistors, small-scale integrated circuits, large-scale and ultra-large-scale integrated circuits.
2。 Features of computer: high speed, high precision, large capacity and logical judgment.
3。 Computer applications: computer aided design CAD, computer aided manufacturing CAM, computer aided teaching CAI, computer integrated manufacturing system CIMS.
4。 Language development of computer: machine language, assembly language and high-level language. There are two ways from a high-level language to a language that can be recognized by a machine: compilation (forming an object program) and interpretation (not forming an object program).
5。 Virus: It is a destructive program with the characteristics of latent, hidden, infectious and destructive.
6。 The main transmission routes of the virus: floppy disk, U disk and network.
7。 Viruses often appear before anti-virus software, that is, there are viruses first and then anti-virus software.
8。 The composition of microcomputer: hardware system and software system. Hardware devices include: arithmetic unit, controller, memory, input device and output device. Arithmetic unit and controller constitute the core part of the computer: CPU (Central Processing Unit). Software system includes system software and application software.
9。 Memory is divided into internal memory (memory) and external memory (hard disk, floppy disk, etc. ). Memory chips have fast access speed, small capacity, high price, slow external storage speed, large capacity and low price.
10。 It can be used as both input device and output device: CD-ROM drive and floppy disk drive.
1 1。 Internal memory is divided into read-only memory (ROM) and random access memory (RAM).
12。 The law of ASCII code (accounting for one byte): from small to large: 0~9, A~Z, a ~ z.
13。 Bit: The smallest unit of information in a computer.
14。 Byte: The smallest unit of storage in a computer.
15。 Byte conversion (b):1b = 8bits1kb =1024b/mb =1024kb1gb =1024mb.
16。 Binary conversion: decimal-binary: except 2, the remainder is reversed;
Binary-Decimal: Expand by weight,
Binary-hexadecimal: four represents one or one represents four.
Special breakthrough of computer first-level knowledge points
1. The main goal of computer network is to realize resource sharing and information transmission.
2. Domain name format: host name. Organization name. Network name. top-level domain
3. Top-level domain names mainly include: COM stands for commercial organizations; EDU stands for educational institutions; GOV stands for government agencies; MIL stands for military organization; NET stands for network support center; ORG stands for international organization.
4. LAN consists of network hardware and network software.
5. Network hardware mainly includes network server, network workstation, network card and communication medium.
6. Network software mainly includes: network operating system, network database management system and network application software.
7. The 7.IP address consists of 32-bit binary numbers (accounting for 4 bytes) or decimal numbers, and each byte is separated by "". "Separate. The value in each byte can be from 0 to 255.
8. According to the geographical scope, computer networks can be divided into local area network, metropolitan area network and wide area network. ChinaDDN network and Chinanet network belong to metropolitan area network, and Internet belongs to wide area network. Novell network belongs to local area network.
9. The structure of the domain name system is the same as that of the IP address, adopting a hierarchical structure, and the format of the domain name is: host name. Organization name. Network name. Top level domain name.
10. In the computer network, two communication entities are located in different geographical locations, and the two processes above them communicate with each other, so it is necessary to coordinate their actions and achieve synchronization by exchanging information, and the exchange of information must be carried out according to the pre-agreed processes, which is the so-called protocol. The commonly used protocol in the Internet is TCP/IP.
1 1. Any data communication system includes a transmitting part, a receiving part and a communication line, and its transmission quality is not only related to the transmitted data signal and the transceiving characteristics, but also related to the transmission medium. At the same time, noise interference inevitably exists along communication lines, which will also affect communication and communication quality. Twisted pair is to twist two insulated copper wires into a regular spiral shape. Twisted pair has poor immunity, is easily interfered by various electrical signals, and has poor reliability. Coaxial cable consists of a hollow cylindrical outer conductor around a single inner conductor. In the aspect of anti-interference, coaxial cable is superior to twisted pair for higher frequencies. Optical fiber cable is the fastest growing transmission medium. Free from external electromagnetic wave interference, good electromagnetic insulation, suitable for application in the environment with serious electrical interference; There is no crosstalk interference, it is not easy to monitor or intercept data, and it is safe and confidential.
12, a bridge is a store-and-forward device connected to a local area network, which is independent of high-level protocols.
13, URL is the abbreviation of uniform resource locator, and URL is the address of web page. By using the correct address, the browser can directly connect to any page of WWW.
14, there are usually two ways to access the network: one is to access through the telephone network (->, that is, dial-up internet access), and the other is to connect to the network through the local area network. In these two ways, the access process of dial-up internet access is: user computer->; Modem->; Telephone network->; ISP——& gt； Internet. As we all know, this method of connecting to the network must have a modem. Access process through local area network: the local area network where the user's computer is located->; Router-> data communication network-> router; ISP——& gt； Internet.
15. According to the Internet domain name code. Net stands for network center. Com stands for business organization. Gov stands for government departments. Org stands for other organizations.
16. The main purpose of establishing a computer network is to realize data communication and resource sharing. The most prominent advantage of computer network is to enjoy resources.
17. The format of e-mail address is: user name+@+computer name+organization name+top-level domain name.
18. The format of email address is: user name @ email host domain name.
19, bit error rate: refers to the ratio of erroneous data in data transmission to total transmission data, which is one of the main performance parameters of communication channel.
20, TCP/IP protocol refers to the transmission control protocol/Internet protocol, its main function is to ensure the reliable transmission of data.
2 1. Data transmission rate: datarate for short refers to the number of bits of binary data transmitted in a unit time, which is usually measured by "kilobits per second" or "megabits per second". It is one of the main technical indexes of data communication system. The transmission rate is expressed in bps or kbps.
22. The browser has introduced many functions into the Windows desktop: the function of browsing web pages from anywhere on the computer, a customizable link toolbar, a browser bar, a content advisor and a safe area for browsing web pages safely.
23. If you want to send and receive e-mail through the Internet, you must meet the following two conditions: first, the computer has been connected through a local area network or a modem; Second, at least one email server has an email account, which can be obtained from an ISP (Internet Service Provider) or a local area network (LAN) administrator. Therefore, after a user registers with an ISP to dial into the network, his e-mail is established on the ISP's host.
24. Hypertext refers to the text containing link pointers (i.e. hyperlinks) of other information. Images and sounds can be realized in ordinary text through the "object" option in "insert", which is not unique to hypertext.
E-mail is the most widely used service on the Internet. Any user's e-mail stored in his own computer can be sent to another Internet user's mailbox through the Internet e-mail service. On the contrary, you can also receive emails from other users. Both the sender and the recipient must have an email account.
26. The domain name server is stored in the Internet host domain name and IP address comparison table.
27.TCP/IP is the protocol standard adopted by the Internet and the most widely used industrial standard in the world. TCP refers to the transmission control protocol, and IP is the Internet protocol.
28. Remote login. This service is used to realize the * * * enjoyment of resources under the network environment. Through remote login, users can turn one terminal into a remote terminal of another host, so that the host can allow external users to use any resources. It uses TELNET protocol, which enables multiple computers to complete a larger task at the same time.
When a PC wants to establish a communication connection with another remote computer, the simplest and most economical way is to connect them through the public telephone system. To this end, it is necessary to install a device called a modem between the serial port of the computer and the telephone system.
30.Modem realizes the connection between computer based on digital signal and telephone system based on analog signal. When a computer sends data, it must be modulated by a modem, and when it receives data, it must be demodulated by a modem.
The function of 3 1. modem is to convert the digital signal and analog signal of the computer to each other for data transmission.
32. The local area network consists of network server, workstation or client, network adapter (network card), transmission medium and network interconnection equipment.
33. Interconnection devices between networks include repeaters, hubs, bridges, routers, gateways and switching integrators.
34. Computer networks can be divided into local area network, metropolitan area network and wide area network.
1。 Localareanetwork (LAN) is a typical application: (1) The distance covered by all hosts in the same room is 10 meter. (2) The coverage distance of all hosts in the same building is100m. (3) The coverage range of all hosts in the same park, factory and yard is 1km. Ethernet, Novell network and token ring network all belong to local area network.
2。 metropolitanarenetwork(MAN)。 Refers to all hosts (working places) distributed in the same city. Coverage is about 10 km.
3。 Wide area network (WAN). Refers to the geographical range of all hosts and workstations in the network, which can cover several kilometers or more, including 10 km, 100 km, 1000 km, such as the same city, the same country, the same continent or even several continents. Chinanet belongs to wide area network.
35.LAN is the abbreviation of local area network; WAN is the abbreviation of wide area network; ISDN is the abbreviation of single-wire communication; WWW is the abbreviation of World Wide Web.
36. Computer networks consist of hardware and software. Hardware includes computer, network card, server and communication line. Software includes * * * network operating system and information resources.
37.TCP/IP is a general term for a large class of protocols used to organize computers and communication devices into networks. More generally, the Internet depends on thousands of networks and millions of computers. And TCP/IP is the glue that connects all this.
38. E-mail is an e-mail system and a non-interactive communication tool between users. It is also the simplest and fastest communication tool provided by the Internet.
39, every computer on the Internet must specify a unique address, called IP address. It is represented by a numeric code similar to a telephone number, accounting for 4 bytes (currently modified to 16 bytes), and the address format usually displayed is four decimal digits separated by dots. For the convenience of users, each IP address is mapped into a name (string) called domain name. The naming rule of domain name is brand name (enterprise name). Unit attribute code. Country code.
40. A modem is a device that converts digital signals into analog signals. For example, when a personal computer is connected to the Internet through a telephone line, the digital signal sent by the sender's computer will be converted into an analog signal through the modem and transmitted on the telephone network, and the receiver's computer will convert the transmitted analog signal into a digital signal through the modem. Part VI: Knowledge points of operation assessment
1, when we input Chinese characters, we may have different operation methods because of different environments or different purposes. To sum up, there are the following points:
(1) Typing while reading (while reading the manuscript)
(2) Want to type (thinking about Chinese content input)
(3) Listening and playing (listening to other people's dictation input)
(4) Speaking and playing (dictation by yourself)
No matter which operation mode is adopted, the input is made according to the coding rules by typing letters, numbers and symbol keys on the keyboard. So far, there are hundreds of Chinese character input methods on the keyboard, and new input methods appear from time to time. Numerous input methods can be summarized into the following three ways:
(1) Pinyin Input Method
Chinese pinyin is used as the code of Chinese characters, and Chinese characters are input by inputting pinyin letters. For those who have studied Chinese Pinyin, this method can be mastered quickly without special training. But for people who can't speak Pinyin or Mandarin well, it is quite difficult to use Pinyin input method.
(2) font input method
Divide a Chinese character into several radicals, radicals or strokes, and then input the keys corresponding to the radicals according to the coding rules. The font input method has low duplication rate and high speed, but anyone must re-learn and memorize a lot of coding rules and Chinese character splitting principles;
(3) Pinyin input method
This is a Chinese character input method combining pinyin and glyph input. Generally speaking, sound is dominant, supplemented by sound and shape, and sound and shape are combined to learn from each other's strengths. This method combines the advantages of pinyin input method and glyph input method, which not only reduces the duplication rate, but also does not need to do a lot of memory. It is not only simple and convenient to use, but also has fast input speed and high efficiency.
There are dozens of common and influential Chinese character input methods at present. Users can choose one or two Chinese character input methods that are most suitable for them according to their own work characteristics.
2. The basic operation topic mainly tests some basic operations of WINDOWS, including the creation, renaming, property setting, moving and copying of files and folders.
Processing instructions
There are many ways to achieve the same operation goal under WINDOWS. Below we only list one operation method for reference only.
(1) create
Create file
You can use WORD, WordPad or other editing software or resource manager to create your own program files or document files. The file created through Explorer has no specific content. In this topic, the method of creating a file by using the resource manager is as follows: select the candidate directory, click the right mouse button, click the "New" command in the shortcut menu, and select a new type. The new command of the "File" option in the resource manager menu can also achieve this goal.
Start WINDOWS Explorer by creating a folder, click the disk drive letter or folder on the right side of the window, and then point to New in the File menu of the window. After clicking "Folder", the words "New Folder" will appear on the right side of the window. Similarly, you can create a new folder by directly typing the folder name and pressing enter.
(2) Move and copy
The movement of files and folders can be done in many ways, and we list one method below. Generally speaking, moving or copying should go through three steps: selecting, cutting (copying) and pasting.
First, choose
Open Explorer and click the file (or folder) you want to move or copy on the right side of the window. You can use the SHIFT key and mouse to select all files (folders) between two files (folders). You can also use CTRL and mouse to select incoherent files (folders).
B, cut (copy)
In the "Edit" menu, select the "Cut" command (if the purpose of the user operation is to move). Or select Copy from the Edit menu (if the purpose of the user operation is to copy).
C, pasting
On the right side of the browser window, select the destination folder of the file or folder you want to move or copy.
Select Paste from the Edit menu.
(3) Renaming
There are many ways to rename a file or folder. Let's list one method.
Click the name of a file or folder with the left mouse button in Explorer (don't click the icon). When a box and a blinking cursor appear on the name of the selected file or folder, you can directly enter a new name at this time.
(4) Delete
Select the file or folder you want to delete in Explorer and choose Delete from the File menu.
(5) attributes
In Explorer, select the file or folder whose properties you want to view, and then select the Properties command in the File menu to view and modify the properties of the file (folder) in the Properties window.
3. Test point: change the font of the text.
1。 Select the text to edit to highlight.
2。 Click Font on the Format menu.
3。 Set the font, font style, font size, etc. In the Font dialog box.
4. Test point: change the character spacing.
1。 Select the text you want to change.
2。 Click Font on the Format menu, and then click the Character Spacing tab.
3。 Please do one of the following:
To widen or narrow the spacing of all selected characters evenly, click the Widen or Narrow option in the Spacing box, and specify the spacing size to adjust in the Point Size box.
;