 Assalamu alaikum viewers, welcome to virtual university. Last time, we talked about primary and secondary memory. In today's lesson, you are going to read about types of memory to be found in a computer. We will follow the usual pattern of reading followed by comprehension exercises, scanning for information, vocabulary exercise and content review exercises. This will be followed by exercises on how language functions operate in English. Now, I will read the text for types of memory. As mentioned previously, one of the most important characteristics of a computer is its capability of storing information in its memory long enough to process it. Not all computers have the same type of memory. In this section, three types of memory will be discussed core memory, semiconductor memory or chip and bubble memory. The memory of the first computers was made up of a kind of grid of fine vertical and horizontal wires. At each intersection where the wires cross, there was a small ferrite ring called a core. Hence you have the name core memory which was capable of being either magnetized or demagnetized. Every intersection had its unique address. Consequently, when an electric current was passed through the wires, the magnetized as well as the un-magnetized cores were identified by their respective addresses. Each core represented a binary digit of either 0 or 1 depending on its state. Early computers had a capacity of around 80,000 bits whereas now it is not surprising to hear about computers with a memory capacity of millions of bits. This has been made possible by the advent of transistors and by the advances in the manufacture of miniaturized circuitry. As a result, main frames have been reduced in both size and cost. Throughout the 1950s, 1960s and up to the mid 1970s, core memory dominated the market. In the 1970s, there was a further development which revolutionized the computer field. This was the ability to etch thousands of integrated circuits onto a tiny piece that is the chip, onto a tiny piece of silicon which is a non-metallic element with semiconductor characteristics. Chips have thousands of identical circuits, each one capable of storing one bit. Because of the very small size of the chip and consequently of the circuits etched on it, faster. Moreover, the size of the components containing the circuitry can be considerably reduced, a step which has led to the introduction of both minis and micros. As a result, computers have become smaller, faster and cheaper. There is one problem with semiconductor memory, however, when power is removed, information in the memory is lost unlike core memory which is capable of retaining information during a power failure. Another development in the field of computer memories is bubble memory. The concept consists of creating a thin film of metallic alloys over the memory board. When this film is magnetized, it produces magnetic bubbles, the presence or absence of which represents one bit of information. These bubbles are extremely tiny, about 0.1 micrometer in diameter, therefore a magnetic bubble memory can store information at a greater density than existing memories which make it suitable for micros. Mobile memories are not expensive, consume little power, are small in size and are highly reliable. There is probably a lot more to learn about them and research in this field continues. Now you have read the paragraph, the passage and we will do one exercise, comprehension and exercise in which you will look at three statements and decide which one does not express the main idea of the text or in another way which one of these three statements expresses the main idea of the text. Second number one, core memory was the first type of computer memory to be developed. Number two, there are at least three different kinds of memory used in computers. Bubble memory is the latest development in computer memory. Now out of these three statements, which one expresses the main idea of the text? Number one, number two or number three? I am sure you guessed the correct answer and that is number two. Number one and three are not the main idea of the text. Number two expresses the main idea which is that there are three different kinds of memory. Number one and three are not main ideas, both are details of the historical development of memory and they do not show the different types of memory there are. Exercise number three, number two sorry which is understanding the passage. You will have a number of statements and you have to decide whether these statements are true or false and you refer to the information that is given in the text. You will decide by referring to the information in the text. After that, you make changes in the false statements. The statements that you think are false, you make the necessary changes so that these false statements become true. Number one, the most important function of a computer is to hold information in its memory in order to process it. It is a true statement. Number two, mini computers, micro computers and main frames all have the same kind of memory. This statement is true. Number three, semiconductor memory was developed before core memory and after bubble memory. It is a false statement. Now, can you correct this and make it a true statement? You can do it by making these changes. Semiconductor chip memory developed after core memory. Semiconductor of chip memory developed after core memory and before bubble memory. You have to add the words of chip or semiconductor or chip memory developed after core memory and before bubble memory. You have to change before and after their positions in the statement. Statement number four, core memory uses small metal rings which can be magnetized or un-magnetized. It is a true statement. Statement number five, the state of the core can be represented by either 0 or 1. It is a true statement. Number six, early computer memories had less storage capacity than newer ones. It is a true statement. Number seven, a transistor and a chip are the same kind of device. It is false and to make this true, you change the word transistor. A chip is a piece of silicon used in transistors and computers. A chip is a piece of silicon used in transistors and computers. Number eight, the development of chips made it possible for mini-computers and micro-computers to be invented. It is a true statement. Number nine, bubble memory is smaller than a chip. Statement is true and the last statement, bubble memory does not have very many advantages. It is a false statement. Now you can make this statement true by making the following changes. Bubble memories are not expensive, consume little power are small in size and highly reliable. The false statement was that bubble memory does not have very many advantages, which is wrong and you can make it true by giving all the facts about bubble memory, which is that bubble memories are not expensive, consume little power are small in size and highly reliable and more research is required in this field. Exercise three, this is a scanning exercise where you scan the text and find the relevant ideas. Now, wherein is this idea given, first there is a core memory and if you look carefully you will find that it is given in paragraph one. Number two, further to this development chips evolved, further to this development chips evolved, where will you locate this, go through the text which is to be found in paragraph three. There are three types of memory board, statement number three, locate this information, wherein the passage is this stated, where are three types of memory board and you will find that it is given there in the very first paragraph. Number four, this consists of producing a thin film over a memory board, this consists of producing a thin film over a memory board. This information is to be found in paragraph four, the fifth statement then semiconductor memory was developed, then semiconductor memory was developed, if you scan through the text you will find that it is in paragraph three, you find this idea in paragraph three. Statement number six, there is still a lot to learn about this process, quickly go over the paragraphs, is it paragraph one, paragraph two, paragraph three or paragraph four and you will find that it is there in paragraph four. Statement number seven, this is made up of thin wires and rings, this is made up of thin wires and rings and this information is to be found in paragraph two. Statement number eight, finally bubble memory was invented, finally bubble memory was invented and you find this information in paragraph four. Now that was exercise three, now we will do one exercise on contextual reference, you look back at the text and find out what the words given in bold refer to and as usual you will notice that these words are all small words. Number one, long enough to process it and you will find this in paragraph one, now what does it in paragraph one in this line long enough to process it, what does it refer to? If you look back at the text you will find that it refers to information. Number two, look in paragraph two and find this phrase, where the wires crossed, where the wires crossed and what does the word where refer to? You will find that it refers back to the word intersection. The intersection where the wires crossed, where refers to the word intersection. Number three, which was capable of being? Look in paragraph two, find this phrase which was capable of being and the highlighted word is which, what does which refer to, which you will find refers to core. Number four, buy their respective addresses, if you look in paragraph two you will find this phrase buy their respective addresses and what does their T-H-E-I-R, what does their refer to? It refers to the word cores, cores with an S plural and number five, look again in paragraph two and locate this information, this has been made possible, this phrase, this has been made possible. What does this refer to and you will find that this refers to the memory capacity of millions of bits, memory capacity, this refers to memory capacity of millions of bits. Now, statement number six, look in paragraph three, when I tell you paragraph three that makes the whole thing very easy, just scan through paragraph three and locate this statement, which revolutionized the computer field, which revolutionized the computer field. Now, which the word which, what does it refer to, it refers to the word development, it was the development, which revolutionized the computer field. Number seven, look in paragraph three for this phrase, each one capable of storing one bit, each one capable of storing one bit, now what does each one refer to? Each one refers to the word chips. Statement number eight, look again in paragraph three, we are still looking at paragraph three and locate this statement of the circuits etched on it, of the circuits etched on it, what does the word it refer to? It refers to the word chip, chip in the singular. In the last one it was chips in the plural, here it is chip. Number nine, it produces magnetic bubble, it produces magnetic bubble and look in paragraph four. This phrase, it produces magnetic bubble and it is the word referring, it refers to the word film, it is the film that produces magnetic bubble. And the last statement, look again in paragraph four and find this statement of which represents one bit, of which represents one bit and of which refers to bubbles. Now we will exercise five and this is a vocabulary exercise, first you have to look for synonyms and then you will look for antonym, synonyms words that are similar in same in meaning. Go back to the text again and you look for in the first paragraph, there is a word which means the same as said, is there a word over there which is the same as the word said. The word is mentioned, mentioned and said are more or less the same in meaning, he said something or so and so mentioned this to me, so they carry the same meaning. In paragraph two, look for a word which is similar to the word own, own, the word is respective, in paragraph two the word there is this word respective, it is the same as own in this context. Again look at paragraph two and find a word which has the same meaning as progress, the same meaning as the word progress, there is a word and the word is advances, advances and progress are at the same meaning. And number four, move on to paragraph three and look for a word which carries the same meaning as the word keeping, in paragraph three there is this word retaining and retaining and keeping can be used for one another, they are the same in meaning. When you retain something you keep it with and move on to paragraph four and find a word which you can substitute for the word appropriate, there is a word there in paragraph four which you can use for the word appropriate, the same in meaning and the word is suitable, now those five were synonyms, let us now look at five more words which are antonyms that is words that are opposite in meaning. Look in paragraph two, in paragraph two I want you to look for the correlative neither nor, is there any word are there correlatives that are the opposite in meaning to neither nor, I made it very easy it has it is either or, again in paragraph two look for a word that is the opposite in meaning to the word bypassed, bypassed when you bypass something you avoid it and you make a detour you go around it. So, what would be the opposite of bypassed and the words are passed through it is there in paragraph two, again still at paragraph two look for a word which is opposite in meaning to the word increased and the word is reduced, the opposite of increased is reduced, move on to paragraph four and look for a word which is the opposite of this phrase not producing, the opposite of not producing would be when you do not produce anything you are not creating and the word is creating, the opposite of not producing is creating. Now, move on to paragraph four and look for a word that is the opposite of the phrase do not use up, do not use up when you use up something what do you do, the opposite would be consume when you do not use up you just let things be as they are. So, the opposite of consume is do not use up, now we do another exercise this time again on vocabulary and you have to select the appropriate form of the word, different forms of the word of a word are given you and you have to choose the appropriate one for that sentence. You can check the differences the difference of meaning in your dictionary, take the first one and you have got the word alter and you have got it is two other forms the word alter it is form altered with the ed ending which at once tells you that it is in the past tense and you have got the word alteration which is a noun statement the first one three sentences when a program does not work properly it is often necessary to make what you choose from the three words given which word would be suitable and the suitable word is alterations it is often necessary to make alterations to it be the omission of data from a program can dash it is results drastically I use the word dash to mean gap you have to fill in the gap with the correct word and the correct word for this statement is alter the omission of data from a program can alter it is results drastically alter meaning change and the last one very simple we have already filled two two gaps so what word is left there is only one word left and that is altered the use of the computer in business has altered the workload of many people has altered number three the third group of words are reduced reduced reduction and you know they all mean to listen to lower the introduction of the computer in the workplace has dash the workload of many people which word is suitable and it is the word reduced reduced has reduced here it is used as a verb has reduced be there will probably be a greater in the consumption of oil in the next decade due to the use of computer technology the word is reduction right and the fourth group of words is from the word create create creation created creative a programmer usually has dash as well as a logical mind a programmer usually has a creative as well as a logical mind creative meaning someone who creates who produces new things alright be it takes a lot of inspiration and hard work to come up with a new dash in computer technology a new it has to be creation a new creation now the word new is adjective telling you something more about the word the noun creation it takes a lot of inspiration and hard work to come up with a new creation in computer technology and the last one computers have certainly dash few opportunities of fraud computers have certainly created few opportunities of fraud you've read the text types of memory now there is a table you complete this table by using the information that you read in types of memory in the text types of memory and notice that the table has five columns they are column number one type number two develop developed meaning period time period in which time period was it developed number three the third column is size and fourth column is composition and the fifth one is memory capacity and you will notice that in this table some of the columns have been filled you have to using your knowledge of the text fill in the gaps the first one for size you have large and then for memory capacity it says 80,000 bits and if you look down in number two it gives you the composition you have to fill in the missing information for number one what could it be what type what type is talking about memory capacity so what type was it the first type of memory was the core and it was developed in the 1950s we already know that the size was large what was its composition composition was it was a grid of vertical and horizontal wires with small ferrite rings at intersection in the same way fill in the second in the second one you have been given the composition but you have not been told what type the size or its memory capacity now which type was the integrated circuits on non-metallic element remember it was the chip so in the first column under type you will write the word chip and when was the chip developed this happened in the early 1970s what was its size you already got the word large in the first one and the chip we know was tiny you will write the word tiny under size and its memory capacity millions so for number two you will write the words chip or type early 1970s for develop when it was developed and for size you will write tiny and for memory capacity you will write the word millions and in the third the third last one all five are left blanks for you so you we have already got core memory we have got chip one and we have got the last one to fill in so it has to be number three bubble and the bubble was developed in the late 1970s the chip was early 1970s the bubble was late 1970s and its size extremely tiny extremely tiny what about its composition it has a thin film over metallic alloys a thin film over metallic alloys and what about its memory capacity it is greater than any existing now again a table is given you and this is a table in which the whole passage that you read it is a revision we revise and you notice for your convenience the paragraphs are already given you you have to fill in the time sequence marker this is again an exercise in which you you just fill in a word which shows the time sequence and the information is already given you so you have got two columns the time sequence marker you have to write down the time sequence marker you have to write down the word which tells you what time a certain thing took place number one you have the word in under time sequence marker you have the word the words there and there is a gap and the word computer and the information is had memories up had memories of a kind of grid of fine vertical and horizontal wires you are already given the words the computer it has to be the word the first computer the time marker is the word first and this is this information you can locate in paragraph 2 again looking at the same paragraph you have been given some information and the information is had a capacity of around 80,000 bits so what had a capacity of around 80,000 bits you have given you have been given one hint and the word is computers so which type of computer which kind you have to fill in the word early early computers right and look at the next one the information is it is not surprising to hear about computers with a memory capacity of millions of bits and you have been given a hint whereas the word is now whereas now and in the next one again the information is given you core memory dominated the market and you have to fill in the time sequence marker which would be throughout the 1950s 60s and up to the mid 70s in the last one move on to paragraph 3 the information given you is there was further development which revolutionized what is the time period you have to fill in that column with the phrase in the 1970s look at a few sentences in the next exercise if you go back to the text you just have to fill in words and these are words that add information they show that you are adding information the first one in the 1970s there was a what word would you use there to show that you are adding information and the word is further in the 1970s there was a further development which revolutionized the computer field second one the size of the components containing the circuitry can be considerably reduced what other word is there to show that you are adding information and the word is more over and in the last one the word you can add the word another. So, this was an exercise to show you that you can there are words to add on information and with that we come to the end of today's lesson Allah Hafiz see you next time.