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Testing the computer program




There are two kinds of errors or bugs with which programmers must deal. The first type is the coding error. Such errors are syntax errors that prevent the language processor from successfully translating the source program to object program code. The language processor identifies the nature and the location of the error on the source program listing, so these errors are relatively easy to find and correct. The second type of bug is the logic error. The computer program can be successfully translated, but the program does not produce the desired results. These errors are generally much more difficult to find and to correct than are coding errors. Logic errors can be avoided through careful planning of the program logic, but it is the programmer's responsibility to test thoroughly all of the program's functions, in order to verify that the program performs according to specifications.

There are many tools provided to the programmer to help in debugging the program logic. These tools are called debug packages or tracing routines. They assist the programmer in following the logic by printing out calculation results and field values used in making logic decisions in the program. In a few cases it may be necessary to use a memory dump — a printout of the instructions and date held in the computer's memory — in order to find the cause of logic errors.

UNIT II

Operational systems

Words and word combinations to be learnt:

Complex - сложный

to consume - потреблять

consumer - потребитель

to realize – понять, осознать

smart - умный

decade – декада, десятилетие

simultaneously - одновременно

top – верх, вершина

on top of DOS – «сверху», на основе ДОС

with a click of a mouse – одним щелчком кнопки мыши

to ship - поставлять

multiple users – многочисленные пользователи

 

 

EXERCISE 1 Read and translate the text using the words and word combinations above

When computers were first introduced in the 1940’s and 50’, every programme written had to provide instructions that told the computer how to use devices such as the printer, how to store information on a disk, as well as how to perform several other tasks not necessarily related to the programme. The additional programme instructions for working with hardware devices were very complex and time-consuming. Programmers soon realized it would be smarter to develop one programme that could control the computer’s hardware, which other programmes could use when they needed it. They created the first operating system.

Today, operating systems control and manage the use of hardware devices such as the printer or mouse. They also provide disk management by letting you store information in files. The operating system also lets you run programmes such as the basic word processor. Lastly, the operating system provides several of its own commands that help you to use the computer.

DOS is the most commonly used PC operating system. DOS is an abbreviation for disk operating system. DOS was developed by a company named Microsoft. MS-DOS is an abbreviation for “Microsoft DOS”. When IBM first released the IBM PC in 1981, IBM licensed DOS from Microsoft for use on the PC and called it PC-DOS. From the users’ perspective, PC-DOS and MS-DOS are the same, each providing the same capabilities and commands.

The version of DOS released in 1981 was 1.0. Over the past decade, DOS has undergone several changes. Each time the DOS developers release a new version, they increase the version number.

Window NT (net technology) is an operating system developed by Microsoft. NT is an enhanced version of the popular Microsoft Windows 3.0, 3.1 programmes. NT requires a 386 processor or greater and 8 Mb of RAM. For the best performance, you have to use a 486 processor with about 16 Mb or higher. Unlike the Windows, which runs on top of DOS, Windows NT is an operating system itself. However, NT is DOS compatible. The advantage of using NT over Windows is that NT makes better use of the PC’s memory management capabilities.

OS/2 is a PC operating system created by IBM. Like NT, OS/2is DOS compatible and provides a graphical user interface that lets you run programmers with a click of a mouse. Also like NT, OS/2 performs best when you are using a powerful system. Many IBM-based PCs are shipped with OS/2 preinstalled.

UNIX is a multi-user operating system that allows multiple users to access the system. Traditionally, UNIX was run on a larger mini computers to which users accessed the systems using terminals and not PC’s. UNIX allowed each user to simultaneously run the programmes they desired. Unlike NT and OS/2, UNIX is not DOS compatible. Most users wouldn’t purchase UNIX for their own use.

Windows 95 and 98, are still the most popular user-oriented systems with a friendly interface and multitasking capabilities. The usage of Windows 95 and its enhanced version Windows 98 is so simple that even little kids learn how to use it very quickly. Windows 95 and 98 are DOS compatible.

The new series of operating system by Microsoft are Windows Millennium, Windows 2000 and Windows XP. Each of these new products is addressed to the both corporate and private clients. New strategy of the Microsoft is aimed at creating “a one of all” product, which will be useful for both the beginners and advanced users.

 

 

EXERCISE 2

Translate words and choose the right meaning for the word:

1.Выполнять

 

a) activate, b)investigate, c)delete, d) perform

2.обеспечивать

 

a) instruct, b)promote, c)provide, d)deal

3.программа

 

a) command, b) control, c) programme, d) system

 

4.разрабатывать

 

a) discover, b) delete, c) edit, d) develop

 

5.загружать

 

a) insert, b) boot, c) process, d) realize

 

6.удалять

 

a) manage, b)install, c)run, d)delete

 

7.редактировать

 

a)switch, b) edit, c)store, d)fill

 

8.совместимый

 

a) interchangeable, b) dependable, c) compatible, d) portable

 

9.улучшенный

 

a) enhanced, b) enlarged, c) entered, d) enriched

 

EXERCISE 3

Answer the questions about the text:

 

1. What problems did programmers face in the 1940’s and 1950’s?

2. Why were the first programmes “complex” and “time consuming”?

3. What are the basic functions of operating system?

4. What does the abbreviation DOS mean?

5. What company developed the first version of DOS operating system?

6. What is the difference between the PC-DOS and MS-DOS?

7. What does the abbreviation NT stand for?

8.Who is the developer of OS/2? 9.What makes UNIX so different from the other operational systems? 10.What are the special features of Windows 95, Windows 98, Windows 2000?

 

EXERCISE 4

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