Pc Software: yesterday, today and tomorrow

How many personal computers are being used around the world? 500 thousand? 1 million? 10 million? Or even more? The answer is: over 20 million PC's (in 1988) are already working around the globe. And every month 500.000 more are being put into work.

Just a few years ago computers were used only by experts or enthusiasts. A confusing number of operating systems was offered, with only a few software packages available. Software developers did not know which opera ting systems might have a future and would be worth it to develop respective applications. Accordingly, users suffered from lack of good software. All this changed in 1981, when IBM introduced its Personal Computer. And IBM's PC used Microsoft's MS-DOS operating system. Within no time a standard operating system was born: MS-DOS from Microsoft. This standard was a solid platform for the development of a wide range of application software

In order to make users quickly familiar with their software a computer based training program was offered as well as Microsoft's Mouse support. The Mouse support helps to reduce the necessary keystrokes up to 60be marked or activated.

An easy use of Microsoft's application, however, is one side only. Microsoft has to offer the huge amount of features.

Microsoft Word, the word processor, includes for example, a document retrieval system and the ability to put graphics into the copy. Microsoft Multiplan, the spread-sheet, offers the possibility to work with 8 different tables and macro-language. And with Microsoft Chart, the business graphic, business or production figures can be shown with a 3D effect.

Tremendous improvements on hardware side offer new opportunities for software. A graphical interface is just one example.

MS-OS/2 is a new operating system and it is again from Microsoft. Microsoft's IVIS-OS/2 is a multitasking operating system. It takes full advantage of the 286 processor and offers users up to 16 MB memory. The increasing hardware performance offers new and exciting possibilities for the creation of even advanced software. Microsoft's founder and chairman, Bill Gates, once said, "My vision is to see a PC on every desk."

7. Прочитайте текст и озаглавьте его.

At the beginning of the computer age, software was developed by hiring a group of programmers to write a program. The style of a program depended on the personal taste and experience of the programmers. A program had the flavour of a work of art, and the programmer was a kind of artist. This method of programming did not cause severe problems at the time the programs that were written were small and not very complex. Then new memory technology based on integrated circuits enormously extended the amount of memory available for programs. This allowed more complex programs to be written for more complex applications; bur the methods of producing programs were not appropriate for large programs. They resulted in delays in development schedules, and also produced programs which were very difficult to maintain. The cost of developing software increased enormously. In order to limit the cost explosion, systematic ways of producing software had to be found; these had to be analogous to the paradigms used by engineers to solve problems. Thus software engineering was born. An early definition of software engineering is as follows: Software engineering is the establishment and use of sound engineering principles in order to obtain economically, software that is reliable and works efficiently on real machines.

First the focus of software engineering research was on technical aspects. There was a strong belief that high level programming languages, abstract description languages, program verification techniques, etc. would solve the

major problems. However it has already been discovered that program development is not only a technical problem. There are many factors which influence the success or failure of a software development project, e.g. the human element which had often been ignored in computing. Social aspects such as the interpersonal relationships between the implementers: the experience of the implementers; relationships with the customer and the nature of the task, e.g. specified or unspecified, are at least as important as the technological factors. The problem is that neither do we know all factors which influence software development nor the extent of the influence of the known factors.

Unit 6

I. Переведите на английский язык. Модель: Multiprogramming allows several jobs to be run at the same time. Многозадачность позволяет / дает возможность прогонять несколько заданий в одно и тоже время.

1. Высокие температуры дали возможность пронести эту реакцию за два часа.

2. Полупроводниковая память позволила подключить память большого объема к миникомпьютерам.

3. Эти методы позволили тщательно исследовать новые данные.

4. База данных позволяет объединять области обработки.

5. Программное обеспечение позволяет решить любую поставленную задачу.

6. Система позволяет набирать текст программы, редактировать его.

7. Самые первые операционные системы позволяли выполнять только одну программу в каждый момент времени.

8. Текстовые процессоры позволяют вам управлять принтером.

9. Внутренняя структура компьютера, основанная на архитектуре фон Неймана, позволяет обрабатывать только один кусок информации в единицу времени.

10. Архитектура компьютеров пятого поколения позволяет обрабатывать несколько задач в одно и то же время.

11. Дополнительный блок питания позволяет сохранить содержимое памяти во время кратковременного отключения электричества.

12. Синхронизация позволяет управлять выполнением процессов, например, процесс останавливается, пока другой процесс не достигнет определенного состояния.

13. Математический сопроцессор позволяет ускоренно выполнять арифметические операции.

14. Форматы вещественных чисел позволяют представлять такие специальные величины, как + и –.

II. Запомните значения слова first и переведите предложения.

the first первый

first впервые; сперва; во-первых

firstly во-первых

at first сначала; сперва

first of all прежде всего

1. Mendeleyev was the first to suggest the correct system of the classification of elements.

2. At first the Periodic Table was met with indifference in scientific circles.

3. First of all the scientists made a lot of experiments, read and analysed a tremendous amount of special literature.

4. Ho first took interest in chemistry when he was still a young man.

5. The scientists had to solve a number of different tasks: firstly, they studied all the existing elements, secondly, they corrected atomic weights of some elements.

available имеющийся; доступный

to be available иметь (в наличии)

1. A number of different computing devices available in our Institute's lab is very great.

2. The computer US-1045 is now, available for beginner's use.

3. Of all the instruments available the control generator is the most suitable for producing electrical impulses.

4. Nearly all the IС devices available on the market today are made on the basis of the semiconductor technique.

5. The electron pairs in germanium structure are bound so strongly to each other and to the nucleus that no free electrons are available to conduct a current through the germanium.

6. The various combinations of modules can be made up with memory kits available from the Bull Micral catalogue.

7. This unit with a floppy tape interface, has high performance characteristics which are fully exploited by the utility programs available from the Bull Micral catalogue.

8. If external direct access to the memory is available, then individual computers can be connected together via their memories.

I. Прочитайте два текста. Чем они отличаются?

А

The IBM Personal Computer 8087 Math Coprocessor option #1501002 allows the IBM Personal Computer to do high speed arithmetic, logarithmic functions, and trigonometric operations with extreme accuracy. The 8087 coprocessor works in parallel with the 8088 processor. The parallel operation decreases operation time by allowing the 8087 to do mathematical calculations while the 8088 continues to do other functions. With appropriate software, this option can significantly improve the speed and precision of doing these operations.

The Macro Assembler can assemble source programs for the 8087 math coprocessor. At assembly time, it is necessary to specify the /R parameter, or have the 8087 pseudo-op in the source, if the 8087 math coprocessor is to be resident in the machine that will be running the application. If 8087 emulation (available in the Fortran and Pascal libraries) is used, specify the /E parameter to generate external linkage.

When generating floating-point variables, the assembler uses the 8087 if installed, otherwise it will use its own (included) emulation routines for this operation. Therefore, for large assembler of floating-point tables, the performance of the assembler will be faster, if the 8087 is present.

The instructions mnemonics for the 8087 are preceded by the letter "F", for example, FADD, or FSUB. The first 5 bits of every instruction opcode for the 8087 are the same (11011 binary). These instructions are

called "ESCAPE"' instructions. When the 8088 and 8087 see this instruction opcode, the 8088 calculates the address of any variables in memory, while the 8087 checks the instruction. The 8087 then takes the memory address from the 8088 if the instruction uses a memory operand.

To access locations in memory, the 8087 takes the local bus from the 8088 when the 8088 finishes its current instruction. When the 8087 is finished with the memory transfer, it returns the local bus to the 8088.

The 8087's busy signal informs the 8088 that it is executing an instruction, and the 8088's wait instruction tests this signal to find out when the 8087 is ready to execute following instructions.

The 8087 can be viewed as an architectural extension of the 8088 processor. It extends the register resources and instruction set of the IBM Personal Computer.

Notes:

coprocessor сопроцессор

option вариант; средство

pseudo-op псевдооперация

linkage связь; согласующее устройство

routine программа; алгоритм

opcode код операции

busy состояние занятости

В

The Intel 80287 Math Coprocessor is a chip that performs complex mathematical calculations. It is designed to extend the arithmetic capability of an 80286 microprocessor. In fact, the IBM PC AT provides an extra socket for an 80287. (The IBM Personal Computer and XT work with a similar chip called the 8087. From a programmer's standpoint, the 8087 and 80287 are nearly identical.)

As you know, the 80286 can already do some arithmetic – but not much. It can operate on only five-digit (two-byte) integers, and provides only the four basic functions: add, subtract, multiply, and divide. On the other hand, the 80287 can perform a wide variety of arithmetic, logarithmic, and trigonometric functions on integer and real numbers up to 18 digits long. And because the 80287's instructions are built into hardware, it can produce a dramatic speed improvement over doing these operations with the 80286.

Intel claims, in fact, that the 80287 can perform numeric operations about 50 to 100 times faster than the 80286 can perform an equivalent software routine. This means, for example, that if an 80286 program takes 2000 microseconds to run a particular arithmetic program, the 80287 may do the same thing in only 20 microsecond!

The 80287 is called a coprocessor because it shares programs with the main processor (the 80286). When you run a program that is designed to use the 80287, the 80286 executes the instructions that it recognizes and the 80287 executes those that it recognizes. Each intercepts its own instructions. (Think of a construction foreman who has two helpers, an Italian and a Spaniard. The Italian worker performs only orders the foreman gives in Italian, while the Spanish worker performs only those given in Spanish.)

Generally, programs written in a high-level language such as BASIC or Pascal use the 80287 automatically However, assembly language requires you to either insert 80287 instructions with the 80286's ESC(escape) instruction or buy an assembler that recognises the 80287 instruction set, such as the IBM Macro Assembler.

III. Переведите предложения, обращая внимание на неличные формы глагола.

1. То use other microprocessor based computers requires rewriting all the code to do the same functions as the Z80.

2. The device to be investigated is set up with a gain of typically 20 to 100.

3. In order to use a word from the drum one must wait for the drum to turn to the proper address before a word can be read out.

4. Devices to assist in working with numbers have been in existence as long as there have been numbers.

5. To achieve greater flexibility and freedom, customers are increasingly demanding interoperability across products and systems from different suppliers.

6. All are designed to be incorporated into flexible information networks.

7. Our goal is to bring the most cost-effective solutions to each customer's particular needs.

8. Over the past several years. Group Bull has undertaken a major program to improve quality and productivity.

9. The original reason for building computers was to provide a means for solving mathematical problems.

10. Much work remains to be done to adapt computers to the requirements of business.

11. To develop a universal programming language is our goal.

12. In order to use a machine either to aid research or to aid teaching, the results, methods are to play an essential role.

2. Прочитайте текст. Спросите своего товарища об архитектуре 8087.