 Assalam-u-Alaikum. Welcome to Virtual University. I hope you are enjoying your lessons. Today's lesson is about mainframes. Large computer systems or mainframes as they are referred to in the field of computer science are those computer systems found in computer installations processing immense amounts of data. These powerful computers make use of very high speed main memories into which data and programs to be dealt with are transferred for rapid access. These powerful machines have a larger repertoire of more complex instructions which can be executed more quickly. Whereas smaller computers may take several steps to perform a particular operation a larger machine may accomplish the same thing with one single instruction. These computers can be of two types, digital and analog. The digital computer or general purpose computer as it is often known make up about 90% of the large computers that are in use. It gets its name because the data that is presented to it are made up of a code consisting of digits, single character numbers. The digital computer is like a gigantic cash register in that it can do calculations in steps one after another at tremendous speed and with great accuracy. Digital computer programming is by far the most commonly used in electronic data processing for business or statistical purposes. The analog computer works something like a car like a car speedometer in that it continuously works out calculations. It is used essentially for problems involving measurements. It can simulate or imitate different measurements by electronic means. Both these computer types, the digital and the analog are made up of electronic components that may require large rooms to accommodate them. At present, the digital computer is capable of doing anything the analog once did. Moreover, it is easier to program, cheaper to operate and cheaper to operate. A new type of scientific computer system called the hybrid computer has now been produced that combines the two types into one. Really powerful computers continue to be bulky and require special provision for their housing, refrigeration systems, air filtration and power supplies. This is because much more space is taken by the input-output devices. The magnetic tape and disk units and other peripheral equipment then by the electronic components that do not make up the bulk of the machine in a powerful installation. The power consumption of these machines is also quite high not to mention the price that runs into thousands of dollars. Now all this was in the past. The future will bring great developments in the mechanical devices associated with computer systems. For a long time these have been the weak link from the point of view of both efficiency and reliability. Now you have read three paragraphs dealing with mainframes and the information that you read dealt with computers in the past. We have moved a long way from that time. Anyway, we will now ask you the similar questions. You are familiar, we will start with the main idea. You have read the three paragraphs. Now can you find out what the main idea of the passage was? Which statement best expresses the main idea of the text? And after you've done that, you will have to say why you eliminated the other choices. The first sentence, hybrid computers are a combination of digital and analog computers. Is that the main idea of the passage? Number two, digital computers are used more than any other type of computer. Is this the main idea? Does this statement express the main idea of the passage? Number three, there are three types of mainframes. There are three types of mainframes. Was the passage about this? Number four, analog computers can do more varied work than digital or hybrid computers. Now out of these four statements, which one? Which statement best expresses the main idea of the text? I'm sure you have made the right selection. It is statement number three. There are three types of mainframes. It is statement number three. There are three types of mainframes. Number one and two. Number one, two and four. Don't express this idea. It is only statement number three. There are three types of mainframes. This statement best expresses the main idea of the text that you've read. Now that was understanding the passage. Now let us look at another way of understanding the text. Right? You will see a number of statements on your screen and you will decide whether these sentences are true or false. This is also a way of understanding your comprehension of the passage that you've read. You will refer to the information in the text and you will judge whether that statement is true or false. After you've done that, the statements that are false, that you think are false and you later on find out that they are true, you can convert them into true statements. The first statement. A mainframe is the type of computer that can sit on top of a desk. A mainframe is the type of computer that can sit on top of a desk. Now is this statement true or false? It is false. A mainframe, now how will you convert this into a true statement? A mainframe is a large computer system requiring a special room. Nowhere does the text say that a mainframe is a computer that is put on top of a desk. So statement number one was false. Let us look at statement number two. Mainframes are very powerful and can execute jobs very rapidly and easily. Now is this statement true or is it false? This is a true statement because your text does say that. This was a true statement. Now the next statement. Statement number three. Digital computers are used more than analog computers. Digital computers are used more than analog computers. Is this statement according to the text or is it false? I am sure you made the correct judgment. It is a true statement because it does say so in the text. Statement number four. The analog computer is far smaller than digital computer and therefore occupies very little space. Listen again. The analog computer is far smaller than the digital computer and therefore occupies very little space. This is a false statement. Now let us correct it and make it true. You can make it true by adding the word both. Both analog and digital computers are used more than analog computers. Analog and digital computers are large computers. Both analog and digital computers are large computers. Statement number five. The hybrid computer is a combination of both digital and the analog computer. The hybrid computer is a combination of both the digital and the analog computer. It is a true statement. Those of you who have studied science know the meaning of hybrid. Hybrid means picture of two. So that statement was true. Now statement number six. The analog computer does its calculations one at a time. The analog computer does its calculations one at a time. True or false? False. Now let us correct this and make it true. The digital computer does its calculations one step at a time. The text did not say that the analog computer does it. It is the digital computer. Now statement number seven. The digital computer continuously works out calculations. The digital computer continuously works out calculations. True or false? Again it is false. And let us make it correct. Let us correct it. Let us make it true. The analog computer continuously works out calculations. All you have to do is change from digital to analog. And statement number eight. Mainframes are huge powerful machines whose peripheral equipments take up a lot of space. Mainframes are huge powerful machines whose peripheral equipments take up a lot of space. True or false? True. I am sure you made the correct choice. It was a true statement. Statement number nine. Mainframes are expensive to buy and to operate. Mainframes are expensive to buy and to operate. Correct. It is a correct statement. And the last statement. Statement number ten. Mainframe technology has reached the end of the road. No further development is needed. Mainframe technology has reached the end of the road. No further development is needed. Well, it is obvious. It is a false statement. And we can make it true by converting this statement into. There will be great developments in computer technology in the future. There will be great developments in computer technology in the future. Now we will do another exercise. You will locate information in your text. I shall give you the clue and you go through the text and locate where this information is. The first statement. Smaller computers may take longer to perform an operation. Smaller computers may take longer to perform an operation. Now this you will find in paragraph one. Just came over the text. Very easy. It is in paragraph one. Statement number two. More technological development is necessary in the mechanical devices associated with computer systems. More technological development is necessary in the mechanical devices associated with computer systems. This information is to be found in paragraph three. There are only three paragraphs in this text. Paragraph three. Have you located it? Right. I am sure you have. Statement number three. Mainframes can operate quickly and execute more complex instructions. This information is to be found in paragraph one. So it should not be difficult for you to locate that information. Statement number four. The hybrid computer is a combination of both digital and analog computers. The hybrid computer is a combination of both digital and analog computers. And the information is in paragraph two. Found it? Statement five. Digital computers are used more than analog computers. Digital computers are used more than analog computers. This information you will find in paragraph two. Have you located it? Good. Statement number six. Mainframes are large powerful computers. Mainframes are large powerful computers. And this is in paragraph one. Right there in front of you in the first paragraph. Shouldn't be difficult to locate. Statement number seven. An analog computer is comparable to a speedometer in the way it operates. An analog computer is comparable to a speedometer in the way it operates. Paragraph two. This information can be located in paragraph two. Found it? Let's move on to number eight. Statement number eight. Digital computers do calculations one after another quickly and exactly. Digital computers do calculations one after the other quickly and exactly. And this information is in paragraph two. Right. Now shall we move on to looking at references. Look back at the text and find out the words or phrases that you see on your screen in bold type. We've done this exercise many times before and it shouldn't be difficult for you anymore. Right. In paragraph one look at the word which the whole phrase which can be executed. This you will find this phrase is in paragraph one which can be executed. And what does the word which refer to? You just have to scan the sentence before the sentence after and you'll find the information. Which refers to instruction? The word which can be executed the word which in this phrase which can be executed. Number two. As it is often known. It in this phrase as it is often known. What does it refer to? If you go back to paragraph two you will notice this phrase. It says as it is often known. What does the word it refer to? It refers to general purpose computer. Number three. In paragraph two you will find this phrase that are presented to it. In paragraph two you will find this phrase that are presented to it. What does the word that refer to? It refers to the word data. That refers to the word data. And number four. In paragraph two again you will find this phrase in that it can do calculations. In that it can do calculations. What does it refer to? The word it refers to digital computers. Number five. In that this is again in paragraph two look for this phrase. In that it continuously works out. In that it continuously works out. And the word is it. It refers to analog computers. This time it is analog computers. In the last phrase it was digital computers. Now let us look at number six. And again it is paragraph two. The second paragraph is fairly long. I am sure you have noticed that. Number six, paragraph two. Both of these computer types. The word both in this phrase. Both of these computer types. And the word both refers to digital and analog computers. That was easy. Number seven. Again paragraph two. That may require a large room. That may require a large room. What does that refer to? That refers to electronic computers. Statement number eight. Again look at paragraph two. And look for the phrase that combines the two types. That combines the two types. What does that refer to? That refers to hybrid computers. And number nine. Now move on to paragraph three. The next two statements deal with paragraph three. Statement number nine. Require special provision for their housing. Require special provision for their housing. What does the word there refer to? T-H-E-I-R. There. It refers to computers in paragraph three. And the last statement. Again in paragraph three. That runs into thousands of dollars. What does the word that refer to? It refers to the price. Now we'll do an exercise where we will look at your vocabulary. Another way to increase your vocabulary. Go back to the text. Refer to the text. And find words that are used in paragraph three. Refer to the text and find words that are similar in meaning. Find synonyms. There is a word that is exactly the same in meaning as the word area. Look in paragraph one and find a word which is more or less the same in this context as the word area. You have the word field over there. Field. Field and area have more or less the same meaning in this context. Number two. Look for a word again in paragraph one. You can use the word acted on. There is a word over there which has the same meaning as acted on. And the word is executed. Executed. Number three. Again refer to paragraph one and look for a word which has the same meaning as do. You do something and the word is accomplish. The word is accomplish. Accomplish and do in this context are synonyms. They are synonymous. One can be used or substituted for the other. Now move on to paragraph two and look for a word which is similar in meaning as composed off. Composed off. Is there a phrase which has the same meaning as composed off? In paragraph two you have a word. A phrase consisting of consisting of and composed of carry the same meaning. Again in paragraph two look for a word which has the same meaning as principally. And the word is essentially. Now we look at words that are opposite in meaning. Again refer back to the text and find antonyms. Find words that are opposite in meaning to the words that I call out. Paragraph one there is a word which is opposite to the word ignored. Opposite in meaning to the word ignored. When you ignore something the opposite would be when you deal with something. And you have the word the phrase deal with. The opposite of deal with would be to ignore. And in paragraph two find a word which is opposite in meaning to seldom. Once in a while the opposite would be often. Coming happening again and again. In paragraph two look for a word which is the opposite in meaning to little. Little something small the opposite would be gigantic correct. And move on to paragraph three and find a word which is opposite to the word small. Opposite to the word small. And the word is bulky huge in size bulky again. Same paragraph look for a word which is the opposite in meaning to weak. Weak meaning not strong. So what would be the opposite of weak? And the word you will find over there is powerful. Powerful. Right. Now we will see a number of words. They are all verbs and well not all of them are not verbs. Some are verbs and some are nouns. You have to choose the most appropriate form to complete the sentence. And you can look up the differences in meaning of those words in your dictionary. The first sentence is it is usually not blank dash space. You fill it with one of the four words given on your screen. And the words are permission permit permissible permitted. It is usually not to smoke in a computer installation. The word is permitted. It is usually not permitted to smoke in a computer installation. B. Computers dash space people to use that use that time more effectively. Computers permit people to use that time more effectively. And C. Building dash space. Building is usually required before starting any renovations in buildings for computer department. Building is usually required before starting any renovations to a building for computer department. So building permission the word is permission. Let us look at another one. Four words continuation continue continuing and continuous. You have three sentences and you have to see which one is correct. A. If computers if micro computer sales dash increase it won't be long before every household has one. And the word is continue. If micro computer sales continue to increase it won't be long before every household has one. B. Computers can do repetitive operations dash without getting bored. Computers can do repetitive operations and the word is continuously without getting bored. And number C. There is a dash interest in discovering new areas where computers can be used. There is a continuing there is a continuing interest in discovery in discovering new areas where computers can be used. And the third group of words are measurement, measure, measured and measurable. A. The analog computer is essentially used for problems involving what? Measurement, measure, measure, measurable it has to be measurement. A. The analog computer is essentially used for solving problem for is used for problems involving measurement. Number B. Because computer equipment is often bulky the area used for a computer installation must be measured out carefully. The first in the first blank you used a noun here it has to be a verb must be measured out carefully. And the last sentence in the third group the number of employees a computer company has can be seen as a dash of its success in the business world. The number of employees a computer company has can be seen as a measure of its success in the business world. And the fourth group of words are association, associate, associated. A. Computers are with speed and accuracy. Computers are associated with speed and accuracy. B. There are many computer dash around the world to which computer professionals belong. What could it be? We've already used the word associated and you are left with two choices. The correct choice would be there are many computer associations around the world to which computer professionals belong. And number C. Very easy. You've used up the other two. You are left with only one choice and that is the one. The correct one. Business dash in different cities often communicate with each other via their computers. Business associates in different cities often communicate with each other via their computers. Right. Now number 5. The fifth group of words. Efficiency, efficient and efficiently. A. Using a hand calculator to do simple mathematics is an dash way of working. Using a hand calculator to do simple mathematics is an efficient way of working. B. Computers can solve problems faster and more dash than humans. Computers can solve problems faster and more efficiently than humans. And C. Dash is important in any service industry. What is important? It is efficiency. Efficiency is important in any service industry. Now we shall review the contents of the text that you have read just to see how far you have grasped the text. And you will go back to your text, refer to your text and select the word that fits in that sentence. The first sentence. The dash dash system is a computer which has combined the features of both the dash and dash computer. Now you know what you have been reading. We have been reading about two types of computers in this text. And the computer that is a combination of both is called a hybrid. The hybrid computer system which combines the features of both the analog and the digital computer. It is used mainly in scientific research. Number two, dash you have to fill in the space over here which computers get their name from the word dash. These are single character numbers that make up the in which the data are presented to the computer for processing. Digital computers get their name from the word digits. Very simple, digit and digital. Digital computers get their name from the word digits. These are single character numbers that make up the code in which the data are presented to the computer for processing. Number three, look at the sentence are usually found in large something. Now what is found in large and your text was about main frames. Main frames are usually found in large computer installations. And number four, the last sentence the most commonly used language of in the business community is the most commonly used language of programming. In the business community is digital. Now first we reviewed the contents of what you had read. Now we shall look at the way the information was organized. What was the main idea of this text that you read? The main idea was that main frames are big powerful machines which process an immense amount of data with great speed and accuracy. That was the main idea of the text that you read and there was a major detail as well. Something that supported the main idea and what was that? That was that there are three types of main frames. Digital, analog and hybrid. Now let me just go over for you. The information in this text that you read was organized in this way. There was one main idea and the main idea was that the main idea was that main frames are big powerful machines. And these machines they work at immense speed, great speed and with great accuracy. That was the main idea and the major detail was that there are three types of main frames. Digital, analog and hybrid. The minor detail was about the digital computer and it told you six details of the digital computer. The first detail was that it is also called general purpose computer. Number two, the second detail was that it makes up 90% of large computers which are now in use. The third detail was that data are presented to it in digits. The fourth minor detail that was given was that the digital computer does calculations in steps. And the fifth minor detail was that it is very common for business or statistical programming. And the sixth detail given you about the digital computer was that it requires a large space to accommodate it. Now that was one minor detail dealing with the digital computer. There was information given you about the analog computer. And the details were number one that the analog computer is continuously does calculations. Number two that it is used for problems dealing with measurement. And the third detail about the analog computer was that it requires a large room to accommodate it. And the fourth that it is more expensive to operate and more difficult to program. And then you were given information about the hybrid computer. And you were told that this computer combines the two analog and digital in one. So that was how your information was organized in this text. Well I am sure you have seen that some of the information that you came across is dated. Not all of it but some of it. Keep reading and be up to date. That is all for now. For now, see you next time.