The Memory of the Modern Supercomputers

The organization of computer memory has received much attention over the years. There are two general ways of partitioning memory, which can be called vertical and horizontal. The incentive for structuring memory in a ver­tical or hierarchical manner is that fast memories cost more per bit than slower ones. Moreover, the larger the memory is, the longer it takes to access items that have been stored randomly. The processing units in most large computers communicate directly with a small, very fast memory of perhaps several hundred words. Data can be transferred to or from one of these disk units at a maximum rate of half a million words per second, and in practice it is possible to maintain data flow between central memory and several disk units simultaneously.

The maximum rate of transfer of information to or from a memory device is known as a bandwidth. In order for the average computing speed not to be dominated by the smaller bandwidth of the lower memory levels, programs must be arranged so that as much computation as possible is done with instruction and data at the higher levels before the need arises to reload the higher level from the one below. This is an important consideration in programming vector operations for supercomputers, whose central-memory bandwidth is small in relation to the megaflop rate that can be sustained for data held in the register set.

Several multiprocessing supercomputers currently under development incorporate a number of independent parallel memory modules that linked to an equal number of independent processors through a high-speed pro­gram-controlled switch so that all the memories are equally accessible to all the processors. For pipelines processors still another kind of horizontal partitioning of central memory has been devised: the memory is divided into a number of "phased" memory banks, so described because they operate with their access cycles out of phase with one another. The rationale for the scheme is that random-access central memories are relatively slow, requiring the passage of a certain minimum number of clock periods between succes­sive memory references. In order to keep vector operands streaming at a rate of one word per clock period to feed a pipeline, vectors are stored with con­secutive operands in different banks. The phase shift that "opens" succes­sively referenced banks is equal to one processor clock period.

The memory of the modern supercomputers – is organized hierarchical­ly. The two register memories are the smallest, followed in capacity by cen­tral memory, extended semiconductor memory and disk memory. The extended semiconductor memory has just begun to appear in supercomput­er installations because rotating-disc technology has not kept pace with the increasing speed of processors.

All the functional units can run concurrently, but not all can run at top speed concurrently because they share common resources, such as data paths 01 memory access cycles. Moreover, conditional branches in the pro­gram interrupt the smooth flow of instructions through the instruction processor. Before the processor issues an instruction, it must wait until it is clear that all the resources needed for the execution of the instruction will be available when they are needed.

Active Vocabulary

accessible	maintain
arrange	manner
average	partition
bandwidth	pipeline
concurrently	references
consideration	relational
execution	reload
extend	simultaneously
flow	smooth
in relation to	structure
incentive	to access
issue	to sustain
item

 

2. Answer the following questions:

1. How many ways of partitioning memory are there?

2. How can they be called?

3. What is the incentive for structuring memory?

4. Does there exist an interconnection of memory capacity and access time to items that have been stored randomly?

5. How do the processing units in the most large computers communicate?

6. How can data be transferred?

7. What is known as a bandwidth?

8. How must be programs arranged?

9. How is the memory of the modern supercomputers organized?

10. Why cannot all the functional units run concurrently?

11. What interrupts the smooth flow of the instructions through the instruction processor?

Reconstruct the text “The Memory of the Modern Supercomputers” into a dialogue.

The main rules governing a conversation in English:

The person who asks questions in a conversation usually controls it. Personal questions should be expressed tactfully.

Add new phrases to the previous ones:

Let’s be realistic about this plan/suggestion, etc.

I / we / you have got to think of other sides of this problem as well.

I think it would be reasonable / well-grounded/good, etc. if we discussed your suggestion in detail.

That’s completely irrelevant/off the point. We’re talking about another problem.

Perhaps we could go back to the main point.

Could you stick to the subject/point, please?

That’s very interesting, but I don’t think it’s really to the point.

4. Annotate the text in English. Use the phrases:

I.

a) The title of the article is...
It is written by prof... and published in London in the
journal..., No.3, vol.4, 2011	on pp.3-10
magazine..., No.3, vol.4, 2011
collection of articles... by... editorial house in 2011
book... by... editorial house in 2011
b) The article... by prof... is published in the journal..., in N.Y., pp.5-10.

II.

a) The article	deals with	the problem of...
	discusses
	touches
	discloses
	is devoted to
The text tells us about...
b) Disclosing the problem the author dwells on (upon) such matters as...
The major	points
	matters	of the text are the following:...
	problems
	issues
c) The author	pays special attention to …
	draws readers’ attention to …
Much	attention is paid to...
Great
Special
The author	concentrates on, focuses on
	stresses, underlines, emphasises
	points out
	dwells on (upon)
	distinguishes between
	speaks in details
	gives the classification

III.

a) As far as I am an expert in... I
consider	the article to be of some (great) interest for …
believe
suppose
think
guess
b)	In my opinion	the article is of	great some	interest for
	From my point of view
	To my mind
	the students in applied science
	the specialists in...
	a wide range of readers

5. Discuss the problems trying to prove your point of view. Use the following phrases:

My point is that …

It seems reasonable to say …

I can start by saying …

I have to admit that …

I have reason to believe that …

Summarizing the discussion …

On the whole …

In the long run …

In conclusion I must say …

1. Why does man seek to create smarter computers?

2. What algorithms must be developed to exploit supercomputers?

3. What computers can be exploited to design better computers?

4. Why does man building more and more powerful machines remain their slave as he has to control them?

5. Will coordination be left to the machines itself in the future?

6. Do such predictions belong to the realm of science fiction, or are these claims possible and realizable in practice?

Writing

Write a presentation about the human brain and electronic brains.

 

Extended reading

Text C. The Brain

 

Read and translate the text into Ukrainian at home. Write an abstract (précis) of the text. Express your personal view on the idea “The more scientists find out, the more questions they are unable to answer”. Reproduce it in class.

The Brain

This century man has made many discoveries about the universe – the world outside himself. But he has also started to look into the workings of that other universe which is inside himself – the human brain. Man still has a lot to learn about the most powerful and complex part of his body – the brain.

In ancient times men did not think that the brain was the centre of men­tal activity. Aristotle, the philosopher of ancient Greece, thought that the mind was based in the heart. It was not until the 18^th century that man real­ized that the whole of the brain was involved in the workings of the mind. During the 19^th century scientists found that when certain parts of the brain were damaged, men lost the ability to do certain things. And so people thought that each part of the brain controlled a different activity. But mod­ern research has found that this is not so. It is not easy to say exactly what each part of the brain does.

In the past 50 years there has been a great increase in the amount of research being done on the brain. Chemists and biologists have found that the way the brain works is far more complicated than they had thought. In fact, many people believe that we are only now really starting to learn the truth about how the human brain works. The more scientists find out, the more questions they are unable to answer. For instance, chemists have found that over 100,000 chemical reactions take place in the brain every second!

Scientists hope that if we can discover how the brain works, the better use we will be able to put it to. For example, how do we learn language? Man dif­fers most from all the other animals in his ability to learn and use language, but we still do not know exactly how this is done. Earlier scientists thought that during a men's lifetime the power of his brain decreases. But it is now thought that this is not so. As long as the brain is given plenty of exercises, it keeps its power. It has been found that an old person who has always been mentally active has a quicker mind than a young person who has done only physical work. It is now thought that the more work we give our brains, the more work they are able to do.

Other people believe that we use only 1% of our brain's full potential. They say that the only limit on the power of the brain is the limit of what we think is possible. This is probably because of the way we are taught as chil­dren. When we first start learning to use our minds, we are told what to do, for example, to remember certain facts, but we are not taught how our mem­ory works and how to make the best use of it.

9.	1. Math Concepts.
2. Programming. Multiprogramming.
3. The Internet Programming Languages.
4.Grammar Revision.

Text A. Math Concepts

Pre-text Exercises

1. Before reading the text, read the following questions. Do you know the answers already? Discuss them briefly with other students to see if they know the answers. The questions will help to give a purpose to your reading:

– Do you know the etymology of the term “mathematics”?

– Is it possible to give a concise and readily acceptable definition of maths as a multifield subject?

– Is it necessary to have strong brains (flexible/abstract /clear thinking) to know mathematics perfectly well?

– Could you state the difference between pure maths and applied maths?

 

2. Learn to recognize international words:

mathematics, etymological, regular, auditor, mental, discipline, connotation, unigue, collection, fraction, irrational, arithmetic, algebra, function, calculus, differential, logical, real, system, geometry, division, structure, concept, axiom, associative, distributive, determine, theorem, deduce, separate, compensate, organic, isolate, province, basic, abstraction, physical, creation, human, negative, operation, multiplication, phenomenon, temperature, observation, total, conception, parallel, specific, progressive, idea, illustrate, constitute, constantly, applications, defect, exist, aspect, fundamental.

Read and translate the text:

Math Concepts

The students of maths may wonder where the word "mathematics" comes from. "Mathematics" is a Greek word, and, by origin or etymologically, it means "something that must be learnt or understood", perhaps "acquired knowledge" or "knowledge acquirable by learning" or "general knowledge". The word "maths" is a contraction of all these phrases. The celebrated Pythagorean school in ancient Greece had both regular and incidental members. The incidental members were called "auditors"; the regular members were named "mathematicians" as a general class and not because they specialized in maths; for them maths was a mental discipline of science learning. What is maths in the modern sense of the term, its implications and connotations? There is no neat, simple, general and unique answer to this question.

Maths as a science, viewed as a whole, is a collection of branches. The largest branch is that which builds on the ordinary whole numbers, fractions, and irrational numbers, or what collectively, is called the real number system. Arithmetic, algebra, the study of functions, the calculus, differential equa­tions, and various other subjects which follow the calculus in logical order are all developments of the real number system. This part of maths is termed the maths of number. A second branch is geometry consisting of several geometries. Maths contains many more divisions. Each branch has the same logical structure: it begins with certain concepts, such as the whole numbers or integers in the maths of number, and such as point, line and triangle in geometry. These concepts must verify explicitly stated axioms. Some of the axioms of the maths of number are the associative, commutative, and distributive properties and the axioms about equalities. Some of the axioms of geometry are that two points determine a line, all right angles are equal, etc. From the concepts and axioms theorems are deduced. Hence, from the standpoint of structure, the concepts, axioms and theorems are the essential components of any compartment of maths. We must break down maths into separately taught subjects, but this compartmentalization taken as a necessity, must be compensated for as much as possible. Students must see the interrelationships of the various areas and the importance of maths for other domains. Knowledge is not additive but an organic whole, and maths is an inseparable part of that whole. The full significance of maths can be seen and taught only in terms of its intimate relationships to other fields of knowledge. If maths is isolated from other provinces, it loses importance.

The basic concepts of the main branches of maths are abstractions from experience, implied by their obvious physical counterparts. But it is noteworthy, that many more concepts are introduced which are, in essence, creations of the human mind with or without any help of experience. Irrational numbers, negative numbers and so forth are not wholly abstracted from the physical practice, for the man's mind must create the notion of entirely new types of numbers to which operations such as addition, multiplication, and the like can be applied. The notion of a variable that represents the quantitative values of some changing physical phenomena, such as temperature and time, is also at least one mental step beyond the mere observation of change. The concept of a function, or a relationship between variables, is almost totally a mental creation. The more we study maths, the more we see that the ideas and conceptions involved become more divorced and remote from experience, and the role played by the mind of the mathematician becomes larger and larger. The gradual introduction of new concepts which more and more depart from forms of experience finds its parallel in geometry and many of the specific geometrical terms are mental creations.

As mathematicians nowadays working in any given branch discover new concepts which are less and less drawn from experience and more and more from human mind, the development of concepts is progressive and later concepts are built on earlier notions. These facts have unpleasant consequences. Because the more advanced ideas are purely mental creations rather than abstractions from physical experience and because they are defined in terms of prior concepts, it is more difficult to understand them and illustrate their meanings even for a specialist in some other province of maths. Nevertheless, the current introduction of new concepts in any field enables maths to grow rapidly. Indeed, the growth of modern maths is, in part, due to the introduction of new concepts and new systems of axioms.

Axioms constitute the second major component of any branch of maths. Up to the 19th century axioms were considered as basic self-evident truths about the concepts involved. We know now that this view ought to be given up. The objective of math activity consists of the theorems deduced from a set of axioms. The amount of information that can be deduced from some sets of axioms is almost incredible. The axioms of number give rise to the results of algebra, properties of functions, the theorems of the calculus, the solution of various types of differential equations. Math theorems must be deductively established and proved. Much of the scientific knowledge is produced by deductive reasoning; new theorems are proved constantly, even in such old subjects as algebra and geometry and the current developments are as impor­tant as the older results.

Growth of maths is possible in still another way. Mathematicians are sure now that sets of axioms which have no bearing on the physical world should be explored. Accordingly, mathematicians nowadays investigate algebras and geometries with no immediate applications. There is, however, some disagreement among mathematicians as to the way they answer the question: Do the concepts, axioms, and theorems exist in some objective world and are they merely detected by man or are they entirely human creations? In ancient times the axioms and theorems were regarded as necessary truths about the universe already incorporated in the design of the world. Hence each new theorem was a discovery, a disclosure of what already existed. The contrary view holds that maths, its concepts, and theorems are created by man. Man distinguishes objects in the physical world and invents numbers and numbers names to represent one aspect of experience. Axioms are man's generalizations of certain fundamental facts and theorems may very logically follow from the axioms. Maths, according to this viewpoint, is a human creation in every respect. Some mathematicians claim that pure maths is the most original creation of the human mind.

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