5. Distributed operating system. It is an operating system configured for distributed computing systems. It is quite different from other operating systems in resource management, communication control and operating system structure. Because the resources of the distributed computer system are distributed on different computers in the system, the demand of the operating system for user resources can't wait for the direct allocation of resources like the general operating system, but it needs to search all the computers in the system and allocate them after finding the required resources. For some resources, such as files with multiple copies, consistency must also be considered. Consistency means that several users read the same file at the same time. In order to ensure consistency, the operating system must control the reading, writing and operation of files, so that multiple users can read a file at the same time, and only one user can modify the file at any time. The communication function of distributed operating system is similar to that of network operating system. Because the distributed computer system is not as widely distributed as the network, and the distributed operating system also supports parallel processing, the communication mechanism it provides is different from that provided by the network operating system and requires high communication speed. The structure of distributed operating system is also different from other operating systems. It is distributed on all computers in the system, and can handle various needs of users in parallel, with strong fault tolerance.
4. What is a view? What are the viewing modes in WORD2000? Answer: A polyhedral orthographic drawing of a machine part drawn by orthographic method is a view. The four buttons in the lower left corner of the status bar of Word 2000 are used to switch between several most commonly used views. Word 2000 provides a general view for text input, a page layout view for web pages, a page view for typesetting and printing, and an outline view for organizing manuscripts. Each view has different functions, and users can selectively apply the appropriate view according to the specific situation.
1. Standard view
In Word 2000, Normal view is the default view mode, which simplifies the layout of the page, so you can type or edit text quickly. The speed of repagination and screen refresh in normal view is the fastest among all kinds of views. In normal view, some information, such as header/footer and graphic notes, is not displayed. To operate the header/footer in normal view, you need to select "Header and Footer" from the menu item of the view to open the header/footer window. Automatic page breaks in normal view are indicated by dashed lines, manual page breaks are indicated by dashed lines with the word "page break", and section break is indicated by double dashed lines with the word "section break", as shown in figure 1. If you want to further improve the display and document processing speed of Word 2000 in normal view, you can choose Options from the Tools menu, click the View tab in the Options dialog box that opens, and then select Draft Font and OK.
2.Web layout view
Web layout view is added in Word 2000, which replaces the online layout view of Word 97 to meet the needs of users. Web layout view is mainly used to edit HTML documents. HTML(*。 Htm) is a web format file. When editing a document in Web layout view, you can see its display effect in a Web browser more accurately. In addition, you can use Word 2000 to create and edit web pages in this view mode.
3. Number of visits
In the page view, you can see the position of the object on the actual printed page. In this view, you can view and edit headers and footers. As long as you double-click the header/footer area with the mouse, Word 2000 will automatically display the header/footer toolbar. You can also adjust margins and work with columns, graphic objects and borders in this view. The dark gray backgrounds at the top and sides of the screen correspond to areas other than the set printing paper type, as shown in Figure 2. Non-printing characters can be displayed or hidden in page view. These non-printing characters will not be printed, but will be displayed as control characters on the screen for viewing or editing documents, such as carriage returns, paragraph marks, tabs, spaces, etc. This makes it easy to see whether extra spaces have been added between words and whether spaces or tabs have been typed. Word uses arrows to indicate tabs and dots to indicate spaces. If you draw graphics or add comments in a document, Word 2000 will automatically switch to page view mode.
4. Outline view
Outline view shows the hierarchical structure of a document, such as chapters, sections, titles, etc. For a long document, users can clearly see its brief overview. In the outline view, a collapsible document can only see the title of a certain level, or the whole document can be seen by expanding the document, and the text can be moved, copied or reorganized by dragging the title. When you enter the outline view, the outline toolbar will automatically appear, including buttons about master documents, which are used to organize and maintain long documents. Master document view can combine multiple Word documents into a master document, and then modify and edit long documents. When browsing or editing two parts of information in a document that are far apart, the display window can be split into two windows, and the upper and lower windows after splitting can use different views, as shown in Figure 4, one is an outline view and the other is a normal view, so that it is very convenient to browse and view related materials.
5. What are the common forms of users surfing the Internet? What equipment do you usually add? A: At present, apart from the traditional and widely used "telephone dialing" and "local area network connection", there are also the emerging "ISDN" and the rapidly expanding broadband access "ADSL". Generally, adsl modem, router and network cable should be added.
6. Briefly describe the process of Chinese character processing. A: Computer data are all represented by binary numbers. When we input numbers, letters and various symbols, the computer does not recognize them directly, but turns them into binary numbers before processing them. Therefore, people must first encode according to certain rules so that each symbol or character corresponds to a binary number. There are various coding methods, and the unification needs standard coding. Now ASC code is widely used in the world. When the symbol is input, the information will be converted into the corresponding ASC binary code through the component, and then input to the host. When information is output (for example, displayed on a display), it is processed by the host computer, and then the binary code is converted into corresponding characters or symbols for output. This process is the process of translating telegraph codes into information.
So, what about Chinese character coding? Chinese characters are different from western languages. English is phonography, which consists of letters, while Chinese characters are ideograms. Each character is composed of basic strokes in various forms. Therefore, Chinese characters can only be treated as character information and need to be represented by a code system.
According to ASC codes, hundreds of Chinese character codes have been developed in China, which can be summarized as the input codes combining glyphs and sounds. Different input codes can find the same Chinese character, because they all refer to a standard, and the input codes all refer to the "internal code" of this Chinese character. At present, the standard internal code used in Chinese mainland is GB code, while that used in Taiwan Province province is BIG5 code, which is why we see strange characters on the website of Taiwan Province province.
The internal code of Chinese characters is different from ASC Ⅱ code. An ASC Ⅱ constitutes a western character, one character accounts for one byte, and one byte is eight times that of binary, and two bytes constitute a Chinese character.
The display of Chinese characters requires not only internal codes, but also Chinese character codes. The font code is composed of dots, which form a graph, and the font is input in binary form. By using the built-in code of Chinese characters to find the address of the code, the text can be clearly displayed on the screen according to the code, and the code is also used in the printer.
7. Briefly describe the differences between compilation and interpretation methods of high-level language processors. A: This question stumped me.
8. What is a modem and what is its function? A: Modem is actually the abbreviation of modulator and demodulator, which is called modem in Chinese. According to the homonym of Modem, it is affectionately called "cat". Usage: The information in the computer is a digital signal composed of "0" and "1", while the telephone line only transmits analog electrical signals. Therefore, when two computers want to transmit data through telephone lines, a device is needed to convert the numbers into analog. This digital-to-analog converter is a modem. When the computer sends data, the modem first converts the digital signal into the corresponding analog signal, which is called "modulation". Before the modulation signal is transmitted to another computer by telephone carrier, the modem of the receiver is also responsible for restoring the analog signal to a digital signal that can be recognized by the computer. This process is called "demodulation". It is through such a digital-to-analog conversion process of "modulation" and "demodulation" that the remote communication between two computers is realized.
9. In WORD, how to set up automatic saving? Answer: If you use WORD, you can open Tools-Options, select the "Save" tab at the top of the opened dialog box, and check the box in front of "Auto-save time interval XX seconds" to select the time. This can avoid the loss of files when the computer suddenly loses power or crashes abnormally, and restore it the next time you open the WORD document. However, you still need to select Save when closing, otherwise the automatically saved file will be deleted.
If you use EXCEL, you can click Tools-Add-ins, which has the function of saving automatically. However, if the computer prompts you that the add-in is not installed, you need to insert the installation location of the source disk or source file where OFFICE is installed. In addition, when EXCEL automatically saves, there is always a dialog box to prompt to save, and the main points need to be confirmed.
What is a computer virus? What are its characteristics? The definition of computer virus "Regulations on the Security Protection of Computer Information System in People's Republic of China (PRC)" has a clear definition of computer virus. Virus "refers to a set of computer instructions or program codes compiled or inserted in a computer program, which destroys computer functions or data, affects the use of the computer and can replicate itself".
Second, the characteristics of computer virus computer virus is a special program, which has the ability of self-replication, strong infectivity, certain latency, specific trigger and great destructiveness.
The inevitability of the existence of three viruses: computer information needs to be accessed, copied and spread. As a form of information, viruses can multiply, infect and destroy. When the viruses gain control, they will actively look for infected targets and spread widely.
The long-term virus of computer virus often spreads by taking advantage of the weakness of computer operating system. Improving system security is an important aspect of virus prevention, but there is no perfect system. Too much emphasis on improving the security of the system will make the system spend most of its time on virus detection, and the system will lose its usability, practicality and ease of use. On the other hand, the requirement of information confidentiality makes it impossible for people to choose between leaking secrets and catching viruses. Virus and anti-virus will exist for a long time as a technical countermeasure, and both technologies will develop with the development of computer technology.
Computer viruses do not come from sudden or accidental reasons. Sudden power failure and accidental errors will produce some random codes and instructions in the computer's disk and memory, but these codes are disorderly and chaotic. Virus is a relatively perfect, exquisite and rigorous code, which is organized in strict order, adapting and coordinating with the system network environment. Viruses don't form by chance, and they need a certain length. This basic length is probabilistic. Viruses are artificial special programs. Popular viruses are written by people on purpose. Most viruses can find author information and source information. According to a large number of data analysis and statistics, the main situation and purpose of virus authors are: some talented programmers are dissatisfied with their bosses in order to express themselves and prove their abilities, for curiosity, for revenge, for congratulations on courtship, and for controlling passwords. Traps reserved for software that can't get money, etc. Of course, some of them are written specifically for political, military, religious, ethnic and patent needs, including some virus research institutions and hackers testing viruses.
Classification of computer viruses According to years of research on computer viruses and scientific, systematic and rigorous methods, computer viruses can be divided into the following categories: According to the method of computer virus attributes, computer viruses can be classified according to the following attributes:
According to the media in which computer viruses exist, viruses can be divided into network viruses, file viruses and boot viruses. Network viruses spread through computer networks and infect executable files in the network. File viruses infect files in computers (such as COM, EXE, DOC, etc.). ), the Boot virus infects the boot sector (boot sector) and system boot sector (MBR) of the hard disk, and there is a mixture of these three situations, such as multi-virus (file and boot) infecting the file and boot sector. This virus usually has complex algorithms and is used a lot.
According to the infection mode of computer virus, it can be divided into resident virus and non-resident virus. After the resident virus infects the computer, it puts its own memory resident part in the memory (RAM), and this part of the program is linked to the system call and merged into the operating system. It remains active until it is shut down or restarted. Non-resident viruses will not infect computer memory when activated. Some viruses will leave a small part in memory, but they are not infected through this part.
According to the destructive ability of computer viruses, they can be divided into the following categories: harmless type has no other influence on the system except reducing the available space of the disk when infected. Non-harmful viruses only reduce memory, display images, and make sounds. Dangerous viruses can cause serious errors in the operation of computer systems. Very dangerous viruses can delete programs, destroy data, and erase important information in the system memory area and operating system. The harm these viruses do to the system is not that there are dangerous calls in their own algorithms, but that when they are infected, they will cause unpredictable and catastrophic damage. Errors caused by viruses in other programs can also destroy files and sectors, and these viruses are also classified according to their destructive ability. Some harmless viruses may now damage new versions of DOS, Windows and other operating systems. For example, there was a "Denzuk" virus in the early days, which worked well on the 360K disk without causing any damage, but it may cause a lot of data loss on the later high-density floppy disk.
Classify computer viruses according to their specific algorithms. According to the specific algorithm of the virus, the virus can be divided into: companion virus, which does not change the file itself, and produces the companion of the EXE file according to the algorithm, with the same name and different extensions (COM). For example, XCOPY. EXE's companion is XCOPY.COM. When a virus writes itself to a COM file, it does not change the EXE file. When DOS loads a file, the satellite is executed first, and then the satellite loads and executes the original EXE file. "Worm" virus spreads through computer network without changing files and data information. It uses the network to spread from the memory of one machine to the memory of other machines, calculates the network address, and sends its own virus through the network. Sometimes they exist in the system and generally do not occupy other resources except memory. Parasitic viruses can be called parasitic viruses except companion viruses and "worm" viruses. They are attached to the boot sector or file of the system and spread through the functions of the system. According to the different algorithms, it can be divided into: practicing viruses contains errors and cannot spread well. For example, some viruses are in the debugging stage. Mysterious viruses generally do not directly modify DOS interrupts and sector data, but internally modify DOS through device technology and file buffer, so it is difficult to see resources and use more advanced technology. Use the free data area of DOS to work. Mutant virus (also known as ghost virus) uses complex algorithms, so that each copy it spreads has different content and length. Their general practice is a decoding algorithm, which mixes irrelevant instructions and changed virus bodies.