（中職）計算機專業(yè)英語unit 3教學課件

1、YCF正版可修改PPT（中職）計算機專業(yè)英語unit 3教學課件Unit 3 Computer Software 3.1 Computer Software Basics 3.2 System Software 3.3 application Software3.4 Software Knowledge wordPhrasesGrammar Reference TranslationComputer software is a general term for organized collections of computer data and the instructions can dir

2、ect the computer to accomplish a task. Software is a basic part of a computer. The computer software is essentially the same as a computer program. In practice, the term “ software” is typically used to describe a commercial product, which might include more than a single program. So we can also say

3、, “ Without software, computers are useless. “ 3. 1. 1 Three Layers Users often see things differently than programmers. People who use modern general purpose computers (as opposed to embedded systems, analog computers, supercomputers, etc. ) usually see three layers of software performing a variety

4、 of tasks; platform, application, and user software. 3. 1 Computer Software Basics下一頁返回1. Platform SoftwarePlatform includes the firmware, device drivers, an operating system, and typically a graphical user interface which, in total, allow a user to interact with the computer and its peripherals (as

5、sociated equipment) . Platform software often comes bundled with the computer, and users may not realize that it exists or that they have a choice to use different platform software. 2. Application SoftwareApplication software or applications are what most people think of when they think of software

6、. Typical examples include Office suites and computer games. Application software is often purchased separately from computer hardware. Sometimes applications are bundled with the computer, but that does not change the fact that they run as independent applications. Applications are almost always in

7、dependent programs from the operating system, though they are often tailored for specific platforms. Most users think of compilers, databases, and other “ system software” as applications. 3. 1 Computer Software Basics上一頁下一頁返回3. User-written SoftwareUser software tailors systems to meet the users sp

8、ecific needs. User software includes spreadsheet templates, word processor macros, scientific simulations, and scripts for graphics and animations. Even E-mail filters are a kind of user software. Users create this software themselves and often overlook how important it is. Depending on how competen

9、tly the user written software has been integrated into purchased application packages, many users may not be aware of the distinction between the purchased packages, and what has been added by fellow co-orkers. 3. 1. 2 Relationship to Computer HardwareComputer software is so called in contrast to co

10、mputer hardware, which encompasses the physical interconnections and devices required to store and run the software. In computers, software is loaded into RAM and executed in the central processing unit. At the lowest level, software consists of a machine language specific to an individual processor

11、. 3. 1 Computer Software Basics上一頁下一頁返回A machine language consists of groups of binary values signifying processor instructions (object codes) , which change the state of the computer from its preceding state. Software is an ordered sequence of instructions for changing the state of the computer har

12、dware in a particular sequence. It is usually written in high-level programming languages that are easier and more efficient for humans to use (closer to natural language) than machine language. High-level languages are compiled or interpreted into machine language object codes. Software may also be

13、 written in an assembly language, essentially, a mnemonic representation of a machine language using a natural language alphabet. Assembly language must be assembled into object codes via an assembler. 3. 1 Computer Software Basics上一頁返回 3. 2. 1 What Is System SoftwareThe simple answer is that system

14、 software is the stuff that makes your computer work. Its roughly analogous to the stem of the human brain-youve got to have it to keep breathing；but with just the stem you arent likely to win any chess tournaments or earn an MBA degree. System software includes the computers basic operating system,

15、 whether thats Windows 2000 or Mac OS on your home computer or something like MVS on a gargantuan mainframe in the data center. The term also usually encompasses any software used to manage the computer and network, which includes diagnostic software and anything used to tune up the computers perfor

16、mance. Novell Netware and other network management packages thus fall under system software. In the mainframe world, system software would include all kinds of utility packages with names like “ Disk Defragmenter. “ 3. 2 System Software下一頁返回3. 2. 2 Subcategories of System SoftwareSystem software per

17、forms tasks essential to the efficient functioning of computer hardware. It includes 4 subcategories; operating systems, utilities, devices drivers and language translator. 1. UtilitiesUtilities are a subcategory of system software designed to augment the operating system by providing a way for a co

18、mputer user to control the allocation and use of hardware resources. Some utilities are included with the operating system；they perform tasks such as preparing disks to hold data, providing information about the files on a disk, and copying data from one disk to another. Microcomputer operating syst

19、ems usually contain programs that provide some utility functions such as copying files. In addition, software packages can be purchased to enhance a users library of system software. With larger computer systems, a set of utility programs are usually supplied by the vendor as part of the system soft

20、ware that is delivered with the computer system. 3. 2 System Software上一頁下一頁返回2. Device DriverWhen you purchase a peripheral device, such as a scanner, you often need to install software that tells your computer how to use the new device. The system software that helps the computer control a peripher

21、al device is called a device driver. Once both the device and the necessary device drivers are installed correctly, the computer can use it to communicate with the device. Of course, you can use the device easily. 3. Language TranslatorSpecial-purpose system software programs called language transla

22、tors are used to convert the programming instructions written by programmers into the machine instructions that a computer can understand. Language translators are written for specific programming languages and computer systems. Knowledge about operating systems will be discussed in the next unit. 3

23、. 2 System Software上一頁返回Although system software handles internal computer functions and helps the computer use peripheral devices, it doesnt transform the computer into the various kinds of machines that you need to write reports, learn how to type or draw pictures. Application software trains the

24、PCs brain for higher cognitive functions rather than just keeping the PC alive and connected to other computers. It is application software that enables a computer to become a multipurpose machine and to perform many different tasks. 3. 3. 1 Document Production SoftwareWhether you are writing a 20 t

25、erm paper, writing software documentation, designing a brochure for our new startup company, or laying out the school newspaper, you will probably use some form of document production software. Document production software assists you with composing, editing, designing, printing, and electronically

26、publishing documents. The three most popular types of document production software are word processing, desktop publishing and Web authoring. 3.3 application Software下一頁返回1 .Word Processing SoftwareWord processing software has replaced typewriters for producing documents such as reports, letters, pa

27、pers, and manuscripts. Individuals use word processing software for correspondence , students use it to write reports and papers, writers use it for novels, reporters use it to compose news stories, scientists use it to write research reports, and business people use it to write memos, reports, lett

28、ers, and marketing material. When documents exist in an electronic format, it is easy to reuse them, share them, and even collaborate on them. Word processing software gives you the ability to create spell-heck, edit and format a document on the screen before you commit to paper. When you are satisf

29、ied with the content of your document, you can use the page layout and formatting features of your word processing software to create a professional-looking printout. Todays best-selling word processing software includes Microsoft Word. 3.3 application Software上一頁下一頁返回2. Desktop Publishing SoftwareD

30、esktop publishing was invented in 1985When personal computers acquired graphical screens, synchronous typographical editing became possible (incorrectly known as “ WYSIWYG” ) ，but the desktop publishing software, was initially used mainly for small-distribution publications such as newsletter clubs.

31、 As the software improved, it became widely adopted throughout the professional publishing world. The superior flexibility and speed of desktop publishing software have greatly reduced the time for magazine publication and allowed more elaborate layouts than would otherwise have been possible. Progr

32、ammable, automated systems like LaTeX mean that long, repetitive, or highly-structured documents can be produced in a fraction of the time that it would take a manually controlled system. The Apple Macintosh, with historically superior graphics capabilities (particularly in the area of typography) ,

33、 and a simple GUI, is highly popular in this application domain and remains one of Apples core markets. 3.3 application Software上一頁下一頁返回3. Web Authoring SoftwareWeb authoring software helps you design and develop customized Web pages that you can publish electronically on the Internet. Only a few ye

34、ars ago, creating Web pages was a fairly technical task that required authors to insert special formatting “ tags” such as. Now, Web authoring software helps nontechnical Web authors by providing easy to use tools for composing the text or a Web page, assembling graphical elements, and automatically

35、 generating formatting tags. Some famous software includes Macromedia Dreamweaver and Microsoft FrontPage. 3. 3. 2 Spreadsheet SoftwareA spreadsheet is a rectangular table of information, often financial information. The word came from “ spread” in its sense of a newspaper or magazine item that cove

36、red two facing pages, extending across the center fold and treating the two pages as a large one. 3.3 application Software上一頁下一頁返回The compound word “ spreadsheet” came to mean the format used to present bookkeeping ledgers-with columns for categories of expenditures across the top, invoices listed d

37、own the left margin, and the amount of each payment in the cell where its row and column intersected. One of the first commercial uses of computers was in processing payroll and other financial records, so the programs were designed to generate reports in the standard “ spreadsheet” format bookkeepe

38、rs and accountants used. The more available and affordable computers themselves became in the last quarter of the 20th century, the more software became available for them, and programs to keep financial records and generate spreadsheet reports were always in demand. Those spreadsheet programs can b

39、e used to tabulate many kinds of information, not just financial records, so the term “ spreadsheet” has developed a more general meaning as information (=data=facts) presented in a rectangular table, usually generated by a computer. 3.3 application Software上一頁下一頁返回3. 3. 3 Database SoftwareA databas

40、e is an information set with a regular structure. A database is usually but not necessarily stored in some machine readable format accessed by a computer. There are a wide variety of databases, from simple tables stored in a single file to very large databases with many millions of records, stored i

41、n rooms full of disk drives. Databases were first developed in the 1960s. A pioneer in the field was Charles Bachman. One way of classifying databases is by the programming model associated with the database. Several models have been in wide use for some time. Historically, the hierarchical model wa

42、s implemented first, then the network model, then the relational model and the flat model reached its zenith. Database software is probably used more frequently in business, government and education rather than by individuals. Microsoft Access, Lotus Approach are popular examples of database softwar

43、e for microcomputers. 3.3 application Software上一頁下一頁返回3. 3. 4 Education and Training SoftwareDo your keyboarding skills need a bit of polish? Do you want to help your children learn and have fun at the same time? Are you the head of human resources and find that your companys managers dont understan

44、d all the fuss about diversity? Where can you turn for help? You might very well find your answers in education and training software. Education and training software helps you learn and practice new skills. For the youngest users, educational software teaches basic reading and counting skills. Inst

45、ruction is presented as games that children can play, and the levels of play are adapted to the childs age and ability. For older students and adults, software is available to help learn languages, learn how to play the piano, prepare for standardized tests, improve keyboarding skills, and even lear

46、n managerial skills for a diverse workplace. Now, more and more exam preparation software is used. Although little research is available on the effectiveness of it, experts believe that the results should be similar to those of in-person coaching courses that improve composite scores by about many p

47、oints. 3.3 application Software上一頁下一頁返回Some education and training software is called “ edutainment software” because it blurs the line between learning and game playing. By far, the most active segment of the edutainment industry is childrens software. Entertainment and education software titles ac

48、count for more than 60 percent of all software sold. 3.3 application Software上一頁返回 3. 4. 1 C and C+ Programming Language1. C LanguageThe C programming language was devised in the early 1970s as a system implementation language for the nascent UNIX operating system. Derived from the type-less languag

49、e BCPL，it evolved a type structure. Created on a tiny machine as a tool to improve a meager programming environment, it has become one of the dominant languages of today. When it became evident that the C programming language was becoming a very popular language available on a wide range of computer

50、s, a group of concerned individuals began to propose a standard set of rules for the use of the C programming language. The group represented all sectors of the software industry and after many meetings, and many preliminary drafts, they finally wrote an acceptable standard for the C language. It ha

51、s been accepted by the American National Standards Institute (ANSI) , and by the International Standards Organization (ISO) . It is not forced upon any group or user, but since it is so widely accepted, it would be economic suicide for any compiler writer to refuse to conform to the standard. 13.4 S

52、oftware Knowledge下一頁返回The characteristics of C language have many aspects, people sum up a lot of features from different angles. The C language has the advantages as follows. (1) Block structured. C programs consist of blocks of program lines called functions. Each function is clearly defined and p

53、erforms a specific task. This block structure also makes a programmer easier to read and more manageable. Because the C language is a language of block structure, it is not limited on some kind of machine, and it can directly deal with characters, digits, and performs arithmetic and logical operatio

54、ns implemented by hardware. (2) Portability. A program written in C for one computer can be carried over to another with little or no modification. This is different from other languages. Other languages may make this claim, but C is the most portable of computer languages available today. Because a

55、ssembly language relies on the mechanical hardware, it is not portable. 3.4 Software Knowledge上一頁下一頁返回(3) Fast and compact. C programs execute at a speed approaching that of assembly language, which is unquestionably the fastest. The C language also has some drawbacks. It has too many prior levels o

56、f calculating symbols to remember, the type examination is too weak, and the change of type is too casual, so the C language is insecure. The size of a program generated in C is less than that obtained by using other complier-type languages. So the C language is an optimal tool that people can use t

57、o describe the system software and other software. In fact, the quality of code of the C language can compare favorably with assembly language. 2. C+ LanguageC+ is based on C. It is a new version of C. It is a general purpose and more comprehensive application programming language developed by Ejarn

58、e Stroustrup at Bell Laboratory. 3.4 Software Knowledge上一頁下一頁返回C+ retains much of C，including a rich operator set, nearly orthogonal design, terseness, and extensibility. C+ is a highly portable language, and translators for it exist on many different machines and systems. C+ compilers are highly co

59、mpatible with existing C programs because maintaining such compatibility was a design objective. Unlike other object-oriented languages, such as Smalltalk, C+ is an extension of an existing language widely used on many machines. 2C+ is a marriage of the low-level with the high-level. C was designed

60、to be a system implementation language, a language close to the machine. C+ adds object-oriented features designed to allow a programmer to create or import a library appropriate to the problem domain. The user can write code at the level appropriate to the problem while still maintaining contact wi