Exam Time for IT. Ч.2. Практикум

Министерство транспорта Российской Федерации

Федеральное государственное автономное образовательное учреждение высшего образования «Российский университет транспорта»

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Кафедра «Русский и иностранные языки»

С. М. Исаева

EXAM TIME FOR IT

Часть 2

Практикум

для студентов специальности

10.05.01«Компьютерная безопасность»

инаправлений

27.03.04«Управление в технических системах»,

09.03.01«Информатика и вычислительная техника»

Москва - 2021 1

УДК 42:004 (76.5) И 85

Исаева С.М. Exam Time for IT. Часть 2: Практикум. – М.: РУТ (МИИТ), 2021. – 52 с.

Практикум предназначен для студентов, обучающихся по специальности 10.05.01 «Компьютерная безопасность», специализация «Информационная безопасность объектов информатизации на базе компьютерных систем», направлениям 27.03.04 «Управление в технических системах», профили «Автоматическое управление в транспортных системах», «Управление и информатика в технических системах», «Системы, методы и средства цифровизации и управления», 09.03.01 «Информатика и вычислительная техника», профиль «IT-сервисы и технологии обработки данных на транспорте» и направлен на подготовку обучающихся к устной части экзамена по дисциплине «Иностранный язык».

© РУТ (МИИТ), 2021

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Topic 1. Computer

It was probably the worst prediction in history. Back in the 1940s, Thomas Watson, boss of the giant IBM Corporation, reputedly forecast that the world would need no more than «about five computers». Six decades later and the global population of computers have now risen to something like one billion machines!

To be fair to Watson, computers have changed enormously in that time. In the 1940s, they were giant scientific and military behemoths commissioned by the government at a cost of millions of dollars apiece; today, most computers are not even recognizable as such: they are embedded in everything from microwave ovens to cellphones and digital radios. What makes computers flexible enough to work in all these different appliances? How come they are so phenomenally useful? And how exactly do they work?

A computer is an electronic machine that processes information — in other words, an information processor: it takes in raw information (or data) at one end, stores it until it’s ready to work on it, chews and crunches it for a bit, then spits out the results at the other end. All these processes have a name. Taking in information is called input, storing information is better known as memory, chewing information is also known as processing, and spitting out results is called output.

Imagine if a computer were a person. Suppose you have a friend who’s really good at math. She is so good that everyone she knows posts their math problems to her. Each morning she goes to her letterbox and finds a pile of new math problems waiting for her attention. She piles them up on her desk until she gets around to looking at them. Each afternoon she takes a letter off the top of the pile, studies the problem, works out the solution, and scribbles the answer on the back. She puts this in an envelope addressed to the person who sent her the original problem and sticks it in her out tray, ready to post. Then she moves to the next letter in the pile. You can see that your friend is working just like a computer. Her letterbox is her input; the pile on her desk is her memory; her brain is the processor that works out the solutions to the problems; and the out tray on her desk is her output.

Once you understand that computers are about input, storage, processing, and output, all you have on your desk makes a lot more sense. Your keyboard and mouse, for example, are just input units — ways of getting information into your computer that it can process. If you use a microphone and voice recognition software, that’s another form of input. Your computer probably stores all your documents and files on a hard-drive: a huge magnetic memory. But smaller, computer-based devices like digital cameras and cellphones use other kinds of storage such as flash memory cards. As for output, your computer almost certainly has a screen and

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probably also stereo loudspeakers. You may have an inkjet printer on your desk too to make a more permanent form of output. Your computer’s processor (sometimes known as the central processing unit) is a microchip buried deep inside. It works amazingly hard and gets incredibly hot in the process. That’s why your computer has a little fan blowing away — to stop its brain from overheating!

A computer works by combining input, storage, processing, and output. All the main parts of a computer system are involved in one of these four processes.

The first computers were gigantic calculating machines and all they ever really did was

«crunch numbers»: solve lengthy, difficult, or tedious mathematical problems. Today, computers work on a much wider variety of problems — but they are all still, essentially, calculations.

Everything a computer does, from helping you to edit a photograph you’ve taken with a digital camera to displaying a web page, involves manipulating numbers in one way or another.

Suppose you’re looking at a digital photo you just taken in a paint or photo-editing program and you decide you want a mirror image of it (in other words, flip it from left to right). You probably know that the photo is made up of millions of individual pixels (coloured squares) arranged in a grid pattern. The computer stores each pixel as a number, so taking a digital photo is really like an instant, orderly exercise in painting by numbers! To flip a digital photo, the computer simply reverses the sequence of numbers so they run from right to left instead of left to right. Or suppose you want to make the photograph brighter. All you have to do is slide the little

«brightness» icon. The computer then works through all the pixels, increasing the brightness value for each one by, say, 10 percent to make the entire image brighter. So, once again, the problem boils down to numbers and calculations.

What makes a computer different from a calculator is that it can work all by itself. You just give it your instructions (called a program) and off it goes, performing a long and complex series of operations all by itself. Back in the 1970s and 1980s, if you wanted a home computer to do almost anything at all, you had to write your own little program to do it. For example, before you could write a letter on a computer, you had to write a program that would read the letters you typed on the keyboard, store them in the memory, and display them on the screen. Writing the program usually took more time than doing whatever it was that you had originally wanted to do (writing the letter). Pretty soon, people started selling programs like word processors to save you the need to write programs yourself.

Today, most computer users buy, download, or share programs like Microsoft Word and Excel. Hardly anyone writes programs any more. Most people see their computers as tools that help them do jobs, rather than complex electronic machines they have to pre-program — and that’s just as well, because most of us have better things to do than computer programming. The beauty of a computer is that it can run a word-processing one minute — and then a photo-editing program five seconds later. In other words, although we don’t really think of it this way, the computer can be reprogrammed as many times as you like. This is why programs are also called software. They’re «soft» in the sense that they are not fixed: they can be changed easily. By contrast, a computer’s hardware — the bits and pieces from which it is made (and the peripherals, like the mouse and printer, you plug into it) — is pretty much fixed when you buy it

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off the shelf. The hardware is what makes your computer powerful; the ability to run different software is what makes it flexible. That computers can do so many different jobs is what makes them so useful — and that’s why millions of us can no longer live without them!

Questions for self-check:

What is a computer?

What comparison of a computer is given in the text? In what way?

How can a computer be characterized from the point of view of its constituent parts? Give brief characteristics of each one.

Why is a computer said to simulate a calculator? How do they differ?

What makes a computer powerful and flexible?

Exercises:

1. Give Russian equivalents of the following words and expressions:

raw information; rise; flexible; screen; bury; input; permanent; chew; crunch; solution; fair; appliance; embed; loudspeaker; output; tedious; share; ink-jet printer; pile up; huge; keyboard; flip; tricky; edit; hard-drive; orderly; get around to; tool; instant; bury.

2. Translate these words and word combinations into English:

3.Find synonyms of the following expressions among the words and word combinations of the previous exercises:

a)monitor, display;

b)complicated, difficult, complex;

c)revise, check over, amend, improve, correct;

d)boring, dull, monotonous; wearisome;

e)device, implement, instrument;

f)piece of equipment, machine;

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g)set in, insert, implant;

h)way out, result, explanation;

i)immediate, direct, instantaneous;

j)go halves, divide, contribute to;

k)enormous, massive, vast, gigantic;

l)collect, amass, load;

m)hide, conceal, put out of sight;

n)adaptable, variable, compliant;

o)just, fair-minded, rational;

p)systematic, methodical, organized;

q)enduring, lasting, eternal, stable.

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Topic 2. Computer architecture

In computer engineering, computer architecture is the conceptual design and fundamental operational structure of a computer system. It is a blueprint and functional description of requirements (especially speeds and interconnections) and design implementations for the various parts of a computer — focusing largely on the way by which the central processing unit (CPU) performs internally and accesses addresses in memory.

It may also be defined as the science and art of selecting and interconnecting hardware components to create computers that meet functional, performance and cost goals.

Computer architecture comprises at least three main subcategories: instruction set architecture, microarchitecture and system design.

A typical vision of a computer architecture as a series of abstraction layers: hardware, firmware, assembler, kernel, operating system and applications.

Instruction set architecture, or ISA, is the abstract image of a computing system that is seen by a machine language (or assembly language) programmer, including the instruction set, memory address modes, processor registers, and address and data formats.

An instruction set is (a list of) all the instructions, and all their variations, that a processor can execute.

Instructions include:

arithmetic instructions such as ADD and SUBTRACT;

logic instructions such as AND, OR, and NOT;

data instructions such as MOVE, INPUT, OUTPUT, LOAD, and STORE;

control flow instructions such as GOTO, IF ... GOTO, CALL, and RETURN. Computers with different microarchitectures can share a common instruction set. For

example, the Intel Pentium and the AMD Athlon implement nearly identical versions of the x86 instruction set, but have radically different internal designs.

Microarchitecture, also known as computer organization is a lower level, more concrete and detailed, description of the system that involves how the constituent parts of the system are interconnected and how they interoperate in order to implement the ISA. The size of a computer’s cache for instance, is an organizational issue that generally has nothing to do with the ISA.

System design includes all of the other hardware components within a computing system such as:

system interconnects such as computer buses and switches;

memory controllers and hierarchies;

CPU off-load mechanisms such as direct memory access;

issues like multi-processing

Once both ISA and microarchitecture has been specified, the actual device needs to be designed into hardware. This design process is called implementation. Implementation is usually not considered architectural definition, but rather hardware design engineering.

Implementation can be further broken down into three (not fully distinct) pieces:

logic implementation — design of blocks defined in the microarchitecture at (primarily) the register-transfer and gate levels;

circuit implementation — transistor-level design of basic elements (gates, multiplexers, latches, etc.) as well as of some larger blocks (ALUs, caches, etc.) that may be implemented at this level, or even (partly) at the physical level, for performance reasons;

physical implementation — physical circuits are drawn out, the different circuit components are placed in a chip floor-plan or on a board and the wires connecting them are routed.

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For CPUs, the entire implementation process is often called CPU design. More specific usages of the term include more general wider-scale hardware architectures, such as cluster computing and Non-Uniform Memory Access (NUMA) architectures.

Some practitioners of computer architecture at companies such as Intel and AMD use more fine distinctions:

macroarchitecture — architectural layers that are more abstract than microarchitecture, e.g. ISA;

assembly ISA — a smart assembler may convert an abstract assembly language common to a group of machines into slightly different machine language for different implementations;

programmer visible macroarchitecture — higher level language tools such as compilers may define a consistent interface or contract to programmers using them, abstracting differences between underlying ISA, UISA, and microarchitectures. E.g. the C, C+ +, or Java standards define different Programmer Visible Macroarchitecture — although in practice the С microarchitecture for a particular computer includes:

o MISA (Microcode Instruction Set Architecture) — a family of machines with different hardware level microarchitectures may share a common microcode architecture, and hence a MISA. Pin Architecture — the set of functions that a microprocessor is expected to provide, from the point of view of a hardware platform. E.g. the x86 A20M, FERR/IGNNE or FLUSH pins, and the messages that the processor is expected to emit after completing a cache invalidation so that external caches can be invalidated. Pin architecture functions are more flexible than ISA functions — external hardware can adapt to changing encodings, or changing from a pin to a message — but the functions are expected to be provided in successive implementations even if the manner of encoding them changes.

o Pin Architecture — the set of functions that a microprocessor is expected to provide, from the point of view of a hardware platform. E.g. the x86 A20M, FERR/IGNNE or FLUSH pins, and the messages that the processor is expected to emit after completing a cache invalidation so that external caches can be invalidated. Pin architecture functions are more flexible than ISA functions — external hardware can adapt to changing encodings, or changing from a pin to a message — but the functions are expected to be provided in successive implementations even if the manner of encoding them changes.

Design Goals.

The exact form of a computer system depends on the constraints and goals for which it was optimized. Computer architectures usually trade off standards, cost, memory capacity, latency and throughput. Sometimes other considerations, such as features, size, weight, reliability, expandability and power consumption are factors as well.

The most common scheme carefully chooses the bottleneck that most reduces the computer’s speed. Ideally, the cost is allocated proportionally to assure that the data rate is nearly the same for all parts of the computer, with the most costly part being the slowest. This is how skillful commercial integrators optimize personal computers.

Cost.

Generally cost is held constant, determined by either system or commercial requirements.

Performance.

Computer performance is often described in terms of clock speed (usually in MHz or GHz). This refers to the cycles per second of the main clock of the CPU. However, this metric is somewhat misleading, as a machine with a higher clock rate may not necessarily have higher performance. As a result manufacturers have moved away from clock speed as a measure of performance. Computer performance can also be measured with the amount of cache a processor has. If the speed, MHz or GHz, were to be a car then the cache is like a traffic light. No matter

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how fast the car goes, it still will not be stopped by a green traffic light. The higher the speed is, and the greater the cache is, the faster a processor runs.

Modern CPUs can execute multiple instructions per clock cycle, which dramatically speeds up a program. Other factors influence speed, such as the mix of functional units, bus speeds, available memory, and the type and order of instructions in the programs being run.

There are two main types of speed, latency and throughput.

Latency is the time between the start of a process and its completion. Throughput is the amount of work done per unit time. Interrupt latency is the guaranteed maximum response time of the system to an electronic event (e.g. when the disk drive finishes moving some data).

Performance is affected by a very wide range of design choices — for example, pipelining a processor usually makes latency worse (slower) but makes throughput better. Computers that control machinery usually need low interrupt latencies. These computers operate in a real-time environment and fail if an operation is not completed in a specified amount of time. For example, computer-controlled anti-lock brakes must begin braking almost immediately after they have been instructed to brake.

The performance of a computer can be measured using other metrics, depending upon its application domain. A system may be CPU bound (as in numerical calculation), I/O bound (as in a webserving application) or memory bound (as in video editing). Power consumption has become important in servers and portable devices like laptops.

Benchmarking tries to take all these factors into account by measuring the time a computer takes to run through a series of test programs. Although benchmarking shows strengths, it may not help one to choose a computer. Often the measured machines split on different measures. For example, one system might handle scientific applications quickly, while another might play popular video games more smoothly. Furthermore, designers have been known to add special features to their products, whether in hardware or software, which permit a specific benchmark to execute quickly but which do not offer similar advantages to other, more general tasks.

Power Consumption.

Power consumption is another design criterion that factors in the design of modern computers. Power efficiency can often be traded for performance or cost benefits. With the increasing power density of modern circuits as the number of transistors per chip scales (Moore’s Law), power efficiency has increased in importance. Recent processor designs such as the Intel Core 2 put more emphasis on increasing power efficiency. Also, in the world of embedded computing, power efficiency has long been and remains the primary design goal next to performance.

Questions for self-check:

How can the term «computer architecture» be determined?

What abstraction layers is it usually divided into?

How many subcategories does computer architecture comprise? What are they? Characterize each one.

What is the name for the process of designing the actual device into hardware? Describe each piece of it.

What criteria are fundamental for the exact form of a computer system?

How can computer performance be measured?

What factor has increased power efficiency in importance?

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