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SIMULA, SMALLTALK, AND EIFFEL



These are the principal specialized "Object Oriented" languages. Simula was developed in the mid-1960s as a language for simulations (simulations of anything you wanted: modelling aircraft movements at an airport, modelling the spread of a disease in a population of individuals, modelling the activities in an automated car wash. Simula was based on Algol-60 but added a variety of constructs that were needed for simulation work. Essentially, it allowed the programmer to create in the computer a set of "objects" (each of which owned some resources and had specified behaviours) that modelled things in the real world. Once the objects had been created, the Simula run-time system could mimic the passage of time and could allow the programmer to track interactions among the objects.

The Smalltalk language was developed by the very innovative research group at Xerox's Palo Alto Research Centre (the same group as invented the prototype for the "Macintosh/Windows" OS and interface). Smalltalk offers a different way of thinking about programming problems. Usually, each problem is treated as if it were totally new. The problem gets analyzed, broken down into subtasks, and then new code is written to handle each of these subtasks. Smalltalk encourages an alternative view; instead of writing new special purpose code, try to find a way of building up a solution to a problem by combining reusable components. The reusable components are Smalltalk objects. A Smalltalk system provides hundreds of different kinds (classes) of "off the shelf " reusable components. Actually, Smalltalk is an interpretive system (a bit like Lisp) and the language is not strictly in the Algol family.

In some respects, Eiffel is the best programming language currently available. It takes advantage of the experience gained with earlier languages like Simula, Pascal, Smalltalk, ADA and others. It is a compiled language (so Eiffel programs are much more efficient than interpreted Smalltalk programs). The basic idea is the same as Smalltalk, i.e. the best way to construct programs is to build them out of reusable objects. Although in many respects very good, Eiffel is restrictive. It enforces the use of an Object Oriented (OO) style. You have to learn several styles, not just OO. For this reason, you are learning C++ because it supports conventional procedural style as well as OO.

Divide the text into the logical parts and give a title to each one.

Put questions to the text.

Discuss it with your groupmates.



 

Module VI

Surfing the Net

Unit 1

Text Study. Internet.

Additional Text. Communication and Media Technology.

Grammar: Conditionals.

Text Study

I. Pre-reading Exercises

1. Repeat the words in chorus:

Charge, governing, internet backbone, Transmission Control Protocol/ Internet Protocol, TCP/IP, quantum mechanics, instantane­ous, knowledge, broadband, withstanding, broadcasting, routers.

2. While reading the text you will come across a number of international words. Try to guess what Ukrainian words they remind of you:

Internet, million, organization, technical aspects, control, private company, client, architecture, machine, technology, program, result, e-mail, popular, information, problem, situation.

3. Pay attention to some grammatical points:

1) The Internet is a computer network made up of thousands of networks world wide. 2) Software can be installed on a client computer to take advantage of the latest access technology. 3) The Internet is very helpful, because it's a huge database of knowledge, from the pictures of family trips to an analysis of quantum mechanics. 4) Everyone should have the Internet because of it instantane­ous communication and huge wealth of knowledge. 5) If we want to find some information in the In­ternet, we are to type address of this data in the browser we use. 6) The data is constantly being directed towards its destination by special computers called routers.

II. Reading

Read the text and be ready to find in the text the answers to the following questions:

  • How many computers are connected to the Internet?
  • How do all computers on the Internet communicate with one another?
  • What interface did web users use in the 70's?

Internet

The Internet is a computer network made up of thousands of networks world wide. No one knows how many computers are connected to the Internet. It is certain, however, that there are millions of them. No one is in charge of the Internet. There are organizations which develop technical aspects of this network, but no governing body is in control. The Internet backbone, through which Internet traffic flows, is owned by private companies.

All computers on the Internet communicate with one another using the Transmission Control Protocol/ Internet Protocol suite, abbreviated to TCP/IP. Computers on the Internet use a client/server architecture. This means that the remote server machine provides files and services to the users’ local client machine. Software can be installed on a client computer to take advantage of the latest access technology.

Public Internet began in the late 70's. In the 70's web users used an interface called Telnet, but now this program is mainly obsolete.

Telnet is most widely deployed in accessing college e-mail accounts. The Internet is very helpful, because it's a huge database of knowledge, from the pictures of family trips to an analysis of quantum mechanics. Everyone should have the Internet because of it instantaneous communication and huge wealth of knowledge. But how to go on the Internet and do a search for information we need? There are two ways to do it. The first is when you know an internet address of data you need and the second one is when you try to find information you need by using a search program. In the beginning we have got to enter any browser you like. It could be an Internet Explorer, Netscape Navigator or Opera, etc. If we have a broadband connection, we connect to the Internet at once. If not - have to set up and connect to our dialup service. Finally, if we want to find some information in the Internet, we are to type address of this data in the browser we use or simply use the existing search-programs such as the Google search program, Rambler search program, Yandex search program or Yahoo search program. They are very simple and popular networks of sites. In these programs we can just type the word or name of thing, we would like to find and then press “Enter”. A search program solves this problem. We get our results in the same window. After we get our results, we simply choose whatever site best matches our query or keep searching.

Besides data, one can get from the Internet; we can also send and receive e-mail or electronic mail. This internet service is cheaper than ordinary mail and much quicker. It is becoming popular day by day. We can find some news from the Internet, because there are many informational servers in the web.

An Internet user also has access to such services as file transfer, vast information resources, interest group membership, interactive collaboration, multimedia displays, real-time broadcasting, shopping opportunities, and much more.

However, there are some problems. The most important problem is security. When you send e-mail, your massage can travel through many different networks and computers. The data is constantly being directed towards its destination by special computers called routers. Because of this, it is possible to get into any of the computers along the route, intercept and even change the data being sent over the internet. But there are many encoding programs available. Not withstanding, these programs are not perfect and can easily be cracked.

Another big and serious problem of the net is control. Yes, there is no effective control in the Internet, because a huge amount of information circulating through the net. It is like a tremendous library and market together. In the future, the situation might change, but now we have what we have.

Vocabulary Notes

in charge —під доглядом, під опікою

backbone —основа, опора

Transmission Control Protocol/ Internet Protocol —протокол передачі даних в мережі інтернет (інтернет-протокол)

remote server machine —віддалений сервер

obsolete['ObsqlJt] застарілий

deployed[dI'plOId] розгорнутий, поширений

e-mail accounts —обліковий запис користувача електронної пошти

instantaneous["Instqn'teInjqs] миттєвий, моментальний

search program —пошукова програма

broadband connection —широкосмуговий зв’язок

dialup service['daIqlAp 'sWvIs]послуга підключення до інтернету через телефонну лінію

query['kwIqrI]запит

file transfer –передача файлів

collaboration[kq"lxbq'reISqn] співробітництво, співпраця

withstand[wID'stxnd]чинити опір, протистояти

Comprehension





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