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Файл:Английский язык для информационных технологий. Часть I. Учебное пособие по формированию иноязычной профессиональной компетенции студентов технических
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8. He (sit) in the garden when a wasp (sting) him in the nose.
9. Claire (go) to Egypt last month.
10. She (have) a beautiful dream when the alarm clock (ring).
11. The car (stop) at the lights.
12. We (drive) home in the middle of the night when we (see) a flashing
light.
13. Soft music (play) when I (go) into the room.
14. (you buy) that bag while I (look) after the children?
15. It (be) peaceful and the birds (sing).
16. Was (Jimmy, already wait) for you when you (get) there?
17. I (ring) at about 3 o’clock yesterday, but you (not pick) up the
phone. – What (you do)? – I (help) Dad in the garden so I probably (not
hear) it.
18. I (lie) in the bath when the phone (ring). It (stop) after a few
rings.
19. It (be) cold when we (leave) the house that day.
V. SPEAKING
5.1. Work in two groups, A and B. Think of advantages and
possible disadvantages of data spaces in information management field.
Then together consider how the disadvantages can be minimized. Use the
Notes below.
Group A. Advantages of data spaces
Group B. Disadvantages of data spaces
Notes:
CLARIFICATION
• I'm afraid it's not quite clear what you mean by...
• I'm sorry I didn't quite follow what you said about...
• I'm afraid I don't understand what... mean(s).
• When you say..., do you mean that...?
ASKING QUESTIONS
• I'd like to know what/when/why/how/who/if...
• Could you tell me what/when/why/how/who/if...?
• I wonder what/when/why/how/who/if...
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• Would you tell me what/when/why/how/who/if...?
• It's interesting to know (to find out)
what/when/why/how/who/if...
102
1. Match the following words with the given definition:
1. processor,
2. keyboard,
3. mouse,
4. floppy
disk
5. hard disk
6. modem
TEST
a) Nonvolatile, no modifiable computer memory,
used to hold programmed instructions to the
system;
b) The part of a television or computer on which
a picture is formed or information is displayed;
c) Rigid disk coated with magnetic material, for
storing computer programs and relatively large
amounts of data;
d) An electronic device that makes possible the
transmission of data to or from computer via
telephone or other communication lines;
e) A set of keys, usually arranged in tiers, for
operating a typewriter, typesetting machine,
computer terminal, or the like;
f) Volatile computer memory, used for creating,
loading, and running programs and for
manipulating and temporarily storing data; main
memory;
g) Central processing unit: the key component of
a computer system, containing the circuitry
necessary to interpret and execute program
instructions;
h) A palm-sized device equipped with one or
more buttons, used to point at and select items
on a computer display screen and for controlling
the cursor by means of analogous movement on
a nearby surface;
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7. monitor
8. ROM
9. RAM.
2. Match the definitions from the table A with their equivalents in
the Russian language from the table B:
Table A Table B
1. DSSPs
(Data Space Support Platforms)
2.DBMS
(Database Management System)
3. Abstraction
4. Catalog and Browse
5. Search and Query
6. Local store and index
7. The Discovery Component
8. The Source Extension
Component
i)
A thin, usually flexible plastic disk coated
with magnetic material, for storing computer
data and program.
a) Система управления базами
данных
b) Абстракция
c) Компонент расширения
источников
d) Каталог и просмотр
e) Компонент раскрытия
f) Платформы поддержки
пространств данных
g) Локальное хранение и
индексирование
h)
Поиск и запрашивание
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UNIT 3. REAL-TIME OPERATING SYSTEM
I. READING
1.1. Read and translate the text “Basic Kernel Services”[23]
BASIC KERNEL SERVICES
Real-time and embedded systems operate in constrained environments
in which computer memory and processing power are limited. They often need
to provide their services within strict time deadlines to their users and to the
surrounding world. It is these memory, speed, and timing constraints that
dictate the use of real-time operating systems in embedded software.
The kernel is the part of an operating system that provides the most
basic services to application software running on a processor. The kernel of a
real-time operating system (RTOS) provides an “abstraction layer” that hides
from application software the hardware details of the processor (or set of
processors) upon which the application software will run.
In providing this “abstraction layer” the RTOS kernel supplies five
main categories of basic services to application software. The most basic
category of kernel services, at the very center is Task Management. This set of
services allows application software developers to design their software as a
number of separate “chunks” of software – each handling a distinct topic, a
distinct goal, and perhaps its own real-time deadline. Each separate “chunk” of
software is called a “task.” Services in this category include the ability to
launch tasks and assign priorities to them. The main RTOS service in this
category is the scheduling of tasks as the embedded system is in operation.
The Task Scheduler controls the execution of application software
tasks, and can make them run in a very timely and responsive fashion.
The second category of kernel services is Inter task Communication and
Synchronization. These services make it possible for tasks to pass information
from one to another, without danger of that information ever being damaged.
They also make it possible for tasks to coordinate, so that they can productively
cooperate with one another. Without the help of these RTOS services, tasks
might well communicate corrupted information or otherwise interfere with each
other. Since many embedded systems have stringent timing requirements, most
RTOS kernels also provide some basic Timer services, such as task delays and
time-outs. Many (but not all) RTOS kernels provide Dynamic Memory
Allocation services. This category of services allows tasks to “borrow” chunks
105
of RAM memory for temporary use in application software. Often these
chunks of memory are then passed from task to task, as a means of quickly
communicating large amounts of data between tasks.
Many (but not all) RTOS kernels also provide a “Device I/O
Supervisor” category of services. These services, if available, provide a
uniform framework for organizing and accessing the many hardware device
drivers that are typical of an embedded system.
In addition to kernel services, many RTOS’s offer a number of
optional add on operating system components for such high-level services as
file system organization, network communication, network management,
database management, user-interface graphics, etc. Although many of these
add-on components are much larger and much more complex than the RTOS
kernel, they rely on the presence of the RTOS kernel and take advantage of its
basic services. Each of these add-on components is included in an embedded
system only if its services are needed for implementing the embedded
application, in order to keep program memory consumption to a minimum.
Many non-real-time operating systems also provide similar kernel
services. The key difference between general-computing operating systems
and real-time operating systems is the need for “deterministic” timing behavior
in the real-time operating systems. Formally, “deterministic” timing means that
operating system services consume only known and expected amounts of time.
Real-time and embedded systems are used in many applications such as
airborne computers, medical instruments, and communication systems.
Embedded systems are characterized by limited processor memory, limited
processing power, and unusual interfaces to the outside world. Real-time
requirements impose stringent time deadlines for delivering the results of
embedded processing.
Study the meaning of the following words and word combinations:
• real-time OS
• an embedded system
• a constraint
• a chunk
• to launch
• to assign
• priority
• scheduling
• corrupted
• stringent
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• temporary
• an add-on component
• to implement
• consumption
• airborne computer
• to impose
1.2. Answer the following questions:
1. What are the constraints that dictate the use of real-time
operating systems?
2. What is an “abstraction layer” in RTOS?
3. What are main categories of basic services in RTOS?
4. Inter task Communication and Synchronization controls the
execution of application software tasks, does it?
5. What does “deterministic” timing mean?
1.3. Find out in the text sentences logically connected with the
following statements:
• Embedded systems as one kind of operating systems.
• Basic concepts of real-time operating systems.
• Development of real-time operating systems.
• Real-time and embedded systems in comparison.
1.4. Find the topical sentences of each passage (i.e. the sentences
containing the central idea of the passage).
1.5. Read and translate the text “Central Processing Unit”[32]
C
ENTRAL PROCESSING UNIT
It is well known in computer science that the words “computer” and
“processor” are used interchangeably. Speaking more precisely, “computer”
refers to the central processing unit (CPU) together with an internal memory.
The internal memory, control, and processing components make up the heart
of the computer system. Manufactures design the CPU to control and carry out
basic instructions for their particular computer. The CPU coordinates all the
activities of the various components of the computer. It determines which
107
operations should be carried out and in what order. The CPU controls the
operation of the entire system by issuing commands to other parts of the
system and by acting on responses. When required it reads information from
the memory, interprets instructions, performs operations on the data according
to the instructions, writes the results back into the memory and moves
information between memory levels or through the input-output ports.
In Digital computers the CPU can be divided into two functional units
called the control unit (CU) and the arithmetic-logical unit (ALU). These two
units are made up of electronic circuits with millions of switches that can be in
one of two states, either on or off. The function of the CU within the central
processor is to transmit coordinating control signals and commands. The
control unit is that part of the computer that directs the sequence of step-bystep operations of the system, selects instructions and data from memory,
interprets the program instructions, and controls the flow between main storage
and the arithmetic-logical unit.
The ALU, on the other hand, is that part of the computer in which the
actual arithmetic operations, namely, addition, subtraction multiplication,
division and exponentiation, called for in the instructions are performed.
Programs and the data, on which the CU and the ALU operate, must be in
internal memory in order to be processed. Thus, if located in secondary
memory devices, such as disks or tapes, programs and data are first loaded into
internal memory.
Study the meaning of the following words and word combinations:
• central processing unit (CPU)
• interchangeably
• precisely
• internal memory
• activity
• to issue
• response
• to interpret
• according to
• level
• input-output port
• control unit (CU)
• arithmetic-logical unit (ALU)
• switch
• step-by-step operations
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• to select
• on the other hand
• exponentiation
• call for
• to load
1.6. Answer the following questions:
1. What words in computer science are used interchangeably?
2. What components make up the heart of the computer system?
3. What is the function of the CPU?
4. Name the sequence of operations the CPU performs (use 5 verbs).
5. What are the CPU functional units made of?
6. What is the function of the CU?
7. What operations are performed in the ALU?
8. Where are data processed?
9. Where are data to be processed loaded?
1.7. Read and translate the text “The CPU Main Components” [36]
T
HE
CPU M
AIN COPMPONENTS
As it is known the two functional units of the CPU are the control
unit (CU) and the arithmetic-logical unit (ALU). The control unit manages
and coordinates the entire computer system. It obtains instructions from the
program stored in main memory, interprets the instructions, and issues
signals that cause other units of the system to execute them. The control
unit operates by reading one instruction at a time from memory and taking
the action called for by each instruction. In this way it controls the flow
between the main storage and the arithmetic-logical unit.
The control unit has the following components:
• a counter that selects the instructions, one at a time, from
memory;
• a register that temporarily holds the instructions read from
memory while it is being executed;
• a decoder that takes the coded instruction and breaks it down into
individual commands necessary to carry it out;
• a clock, which produces marks at regular intervals. These timing
marks are electronic and very rapid.
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The sequence of control unit operations is as follows. The next
instruction to be executed is read out from primary storage into the storage
register. The instruction is passed from the storage register to the instruction
register. Then the operation part of the instruction is decoded so that the proper
arithmetic or logical operation can be performed. The address of the operand is
sent from the instruction register to the address register. At last the instruction
counter register provides the address register with the address of the next
instruction to be executed. The arithmetic-logical unit (ALU) executes the
processing operations called for by the instructions brought from main memory
by the control unit. The arithmetical-logical unit performs binary arithmetic,
the logical operations, and some special functions.
Data enter the ALU and return to main storage through the storage
register. The accumulator serving as a register holds the results of processing
operations. The results of arithmetic operations are returned to the accumulator
for transfer to main storage through the storage register. The comparer
performs logical comparisons of the contents of the storage register and the
accumulator. Typically, the comparer tests for conditions such as "less than",
"equal to", or "greater than".
So as you see the primary components of the arithmetic-logical unit
are banks of devices, which are called registers. Their purpose is to hold the
numbers involved in the calculation and hold the results temporarily until they
can be transferred to memory. At the core of the ALU is a very high-speed
binary adder, which is used to carry out at least the four basic arithmetic
functions (addition, subtraction, multiplication and division). The logical unit
consists of electronic circuitry, which compares information and makes
decisions based upon the results of the comparison.
Study the meaning of the following words and word combinations:
• to manage
• to obtain
• to cause
• flow
• counter
• register
• instruction register
• storage register
• address register
• temporarily
• decoder
• operand address
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