A. Comprehension

1. Define the term 'computer data storage'.

2. Answer these questions:

1. How is the form of semiconductor storage called?

2. What are die mass storage devices?

3. Why does a computer system usually contain several kinds of storage?

4. Which part is me most important of every computer? Why?

5. How significant is memory for a processor?

6. What is storage hierarchy based on?

7. Why did me invention of a transistor cause a revolution?

8. How do the two more sub-layers of me primary storage func- tion, besides main large-capacity RAM?

9. What are me ways of main memory connection to die CPU? 10. How is die small startup program (BIOS) used?

11. What are the reasons of some embedded systems' working wimout RAM, exclusively on ROM?

12. How can the difference between secondary storage devices be illustrated?

13. What does me concept of virtual memory allow?

14. What steps does a computer need to pass to read information from me tertiary storage?

15. Off-line storage increases a general information security, doesn't it? Why?

3. Give brief characteristics of each type of storage.

4. Summarize the text using the words from Vocabulary Exercises.

B. Vocabulary

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

off-line storage; disaster; bit string; semiconductor storage; chunk; delay line; magnetic drum; storage hierarchy; jukebox; Wil- liams tube;

permanent; versatile; tertiary; cumbersome; temporary; merely;

retain; rotate; so far.

6. Find the word alien to the given synonymic group among the words and word combinations from the previous exercise, giving your reasons:

1. failure, misfortune, latency, catastrophe, ruin, disaster;

1. everlasting, permanent, volatile, eternal, undying, stable, unending;

2. retain, keep, hold, preserve, immune;

3. memory section, chunk, source code, data portion;

2. multipurpose, adaptable, versatile, tertiary, many-sided, uni- versal;

4. turn around, revolve, rotate, spin, allocate;"

3. weighty, cumbersome, awkward, remote, burdensome, bulky;

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8. line feed, autonomous memory device, independent memory, stand-alone storage system;

9. just, only, simply, purely, merely, lossy;

10. momentary, temporary, crucial, short-term, brief, transi- tory.

7. Translate the words/expressions into English:

бедствие, несчастье; поворачивать, вращать; только, просто; временный; участок памяти, часть данных; держать, вмешать, сохранять; третичный; линия задержки; до сих пор, пока; иерархия запоминающих устройств; автомат смены дисков; громоздкий, объемный; полупроводниковое ЗУ; битовая стро- ка; автономное ЗУ; постоянный, долговременный; магнитный барабан; многоцелевой, универсальный; запоминающая ЭЛТ (электронно-лучевая трубка).

С. Reading and Discussion

8. Read the text and answer the question: What allows information to be overwritten multiple times ? Find the words in the text and translate the sentences which contain them.

predominantly vanish

random access sequential access

seek cycle

mutable content-addressable storage

hash value pertaining to

nanosecond contiguous

Characteristics of Storage

Volatility of Information

Non-volatile memory will retain die stored information even if it is not constantly supplied with electric power. It is suitable for long-term storage of information. Nowadays it is used for most of secondary,

tertiary, and off-line storage. In 1950s and 1960s, it was also used for primary storage, in the form of magnetic core memory.

Volatile memory requires constant power to maintain the stored information. The fastest memory technologies of today are volatile ones (not a universal rale). Since primary storage is required to be very fast, it predominantly uses volatile memory.

Dynamic memory is a kind of volatile memory which also requires the stored information to be periodically re-read and re-written, or refreshed, otherwise it would vanish.

Ability to Access Non-Contiguous Information

Random access means that any location in storage can be accessed at any moment in approximately the same amount of time. Such char- acteristic is well suited for primary storage.

Sequential access means that the accessing a piece of informa- tion will take a varying amount of time, depending on which piece of information was accessed last. The device may need to seek (e.g. to position the read/write head correctly), or cycle (e.g. to wait for the correct location in a revolving medium to appear below the read/write head).

Ability to Change Information

Read/write storage, or mutable storage, allows information to be overwritten at any time. A computer wimout some amount of read/write storage for primary storage purposes would be useless for many tasks. Modern computers typically use read/write storage also for secondary storage.

Read only storage retains the information stored at the time of manufacture, and write once storage (WORM) allows the information to be written only once at some point after manufacture. These are called immutable storage. Immutable storage is used for tertiary and off-line storage. Examples include CD-R.

Slow write, fast read storage is read/write storage which allows information to be overwritten multiple times, but with the write op- eration being much slower than the read operation. Examples include CD-RW.

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to be differentiated. Also accessing media sequentially, as opposed to randomly, typically yields maximum throughput.

9. Match the beginning of each sentence from the left column with the rest part of it in the right column.

Addressability of information

In location-addressable storage, each individually accessible unit of information in storage is selected with its numerical memory address. In modern computers, location-addressable storage usually limits to primary storage, accessed internally by computer programs, since location-addressability is very efficient, but burdensome for humans.

In file system storage, information is divided into files of variable length, and a particular file is selected with human-readable directory and file names. The underlying device is still location-addressable, but the operating systemof a computer provides the file system abstraction to make the operation more understandable. In modern computers, secondary, tertiary and off-line storage use file systems.

In content-addressable storage, each individually accessible unit of information is selected with a hash value, or a short identifier with number pertaining to the memory address the information is stored on. Content-addressable storage can be implemented using software (computer program) or hardware (computer device), with hardware being faster but more expensive option.

Capacity and Performance

Storage capacity is the total amount of stored information that a storage device or medium can hold. It is expressed as a quantity of bits or bytes (e.g. 10.4 megabytes).

Storage density refers to the compactness of stored information. It is the storage capacity of a medium divided with a unit of length, area or volume (e.g. 1.2 megabytes per square inch).

Latency is the time it takes to access a particular location in stor- age. The relevant unit of measurement is typically nanosecond for primary storage, millisecond for secondary storage, and second for tertiary storage. It may make sense to separate read latency and write latency, and in case of sequential access storage, minimum, maximum and average latency.

Throughput is the rate at which information can be read from or written to the storage. In computer data storage, throughput is usually expressed in terms of megabytes per second or MB/s, though bit rate may also be used. As with latency, read rate and write rate may need

1. Non-volatile memory

2. Random access

3. Volatile memory

4. Read only storage

5. Dynamic memory

6. In location-addressable storage

7. Storage capacity

8. Storage density

9. Mutable storage

10. In content-addressable storage

11. Sequential access

1. means that any location in storage can be accessed at any moment in approximately the same amount of time.

2. requires constant power to main- tain the stored information.

3. allows information to be over- written at any time.

4. is used for most of secondary, tertiary, and off-line storage.

5. is the total amount of stored information that a storage device or medium can hold.

6. refers to the compactness of stored information.

7. means that the accessing a piece of information will take a varying amount of time, depending on which piece of information was accessed last.

h) is a kind of volatile memory which also requires the stored information to be periodically re- read and re-written, or refreshed, otherwise it would vanish.

i) retains the information stored at the time of manufacture, and write once storage (WORM) allows the information to be written only once at some point after manufacture.

j) the time it takes to access a par- ticular location in storage.

k) each individually accessible unit of information in storage is selected with its numerical memory address.

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12) Latency 1) each individually accessible unit

of information is selected with a hash value, or a short identifier with number pertaining to the memory address the information is stored on.

10. Read the text and ask 7 questions covering essential problems of the text to your group-mates.

Fundamental Storage Technologies

Semiconductor Storage

Semiconductor memory uses semiconductor-based integrated circuits to store information. A semiconductor memory chip may contain millions of tiny transistors or capacitors. Both volatile and non-volatile forms of semiconductor memory exist. In modern comput- ers, primary storage almost exclusively consists of dynamic volatile semiconductor memory or dynamic random access memory. Since the turn of the century, a type of non-volatile semiconductor memory known as flash memory has steadily gained share as off-line storage for home computers. Non-volatile semiconductor memory is also used for secondary storage in various advanced electronic devices and specialized computers.

Magnetic Storage

Magnetic storage uses different patterns of magnetization on a magnetically coated surface to store information. Magnetic storage is non-volatile. The information is accessed using one or more read/write heads. Since the read/write head only covers a part of me surface, magnetic storage is sequential access and must seek, cycle or bom. In modern computers, me magnetic surface will take these forms:

Magnetic disk;

Floppy disk, used for off-line storage;

Hard disk, used for secondary storage;

Magnetic tape data storage, used for tertiary and off-line stor- age.

In early computers, magnetic storage was also used for primary storage in a form of magnetic drum, or core memory, core rope memory, thin film memory, twistor memory or bubble memory. Also unlike today, magnetic tape was often used for secondary storage.

Magnetic storage media

Wire (1898) • Tape (1928) • Drum (1932) • Ferrite core (1949)

• Hard disk (1956) • Stripe card (1956) • MICR (1956) • Thin film (1962) • CRAM (1962) • Twistor (-1968) • Floppy disk (1969) • Bubble (-1970) • MRAM (2003)

Optical Storage

Optical storage, in the case of typical Optical discs, uses tiny pits etched on the surface of a circular disc to store information, and reads this information by illuminating the surface with a laser diode and observing the reflection. Optical disc storage is non-volatile and se- quential access. The following forms are currently in common use:

CD, CD-ROM, DVD: read only storage, used for mass distribu- tion of digital information (music, video, computer programs)

CD-R, DVD-R, DVD+R: write once storage, used for tertiary and off-line storage

CD-RW, DVD-RW, DVD+RW, DVD-RAM: slow write, fast read storage, used for tertiary and off-line storage

Magneto-optical disc storage is optical disc storage where the magnetic state on a ferromagnetic surface stores information. The information is read optically and written by combining magnetic and optical methods. Magneto-optical disc storage is non-volatile, sequential access, slow write, fast read storage used for tertiary and off-line storage.

3D optical data storage has also been proposed.

Optical storage media

Compact Disc (1982) : CD-R (1988) • CD-RW (1997)

DVD (1995): DVD-RAM (1996) • DVD-R (1997) • DVD-RW (1999) • DVD+RW (2001) • DVD+R (2002) • DVD+R DL (2004)

• DVD-R DL (2005)

Other: Microform (1870) • Laserdisc (1958) • UDO (2003) • ProData (2003) • UMD (2004) • Blu-Ray Disc (2006) • HD DVD (2006)

Magneto-optic Kerr effect (1877): MiniDisc (1991) Optical Assist: Laser turntable (1986) • Floptical (1991) • Super DLT(1998)

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Other Early Methods

Paper Data Storage

Paper tape and punch cards have been used to store information for automatic processing since the 1890s, long before general-purpose computers existed. Information was recorded by punching holes into the paper or cardboard medium, and was read by mechanically (or, later, optically) sensing whether a particular location on the medium was solid or contained a hole.

Paper data storage media

Writing on Papyrus (c. 3000 ВС) • Modern Paper (105 AD)

Punched card (1725) • Punched tape (1846) • Book music (1863) • Ticker tape (1867) • Piano roll (1880s) • Optical character recogni- tion (1929) • Barcode (1948) • Paper disc (2004)

Vacuum Tube Memory

A Williams tube used a cathode ray tube, and a Selectron tube used a large vacuum tube to store information. These primary stor- age devices were short-lived in the market, since Williams tube was unreliable and Selectron tube was expensive.

Electro-Acoustic Memory

Delay line memory used sound waves in a substance such as mercury to store information. Delay line memory was dynamic vola- tile, cycle sequential read/write storage, and was used for primary storage.

Proposed Methods

Phase-change memory uses different mechanical phases of phase change material to store information, and reads the information by observing the varying electric resistance of the material. Phase-change memory would be non-volatile, random access read/write storage, and might be used for primary, secondary and off-line storage.

Holographic storage stores information optically inside crystals or photopolymers. Holographic storage can utilize the whole volume of the storage medium, unlike optical disc storage which is limited to a small number of surface layers. Holographic storage would be non-volatile, sequential access, and either write once or read/write storage. It might be used for secondary and off-line storage.

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Molecular memory stores information in polymers that can store electric charge. Molecular memory might be especially suited for primary storage.

capacitor; core memory; bubble memory; pit; etch; delay line memory; mercury

11. Agree or disagree with the following statements. Correct the wrong ones.

1. Magnetic storage is optical disc storage where the magnetic state on a ferromagnetic surface stores information.

2. Optical storage uses semiconductor-based integrated circuits to store information.

3. A Williams tube uses different mechanical phases of phase change material to store information, and reads the information by observing the varying electric resistance of me material.

4. Delay line memory used sound waves in a substance such as mercury to store information, was dynamic volatile, cycle sequential read/write storage, and was used for primary stor- age.

5. Holographic storage stores information in polymers that can store electric charge. Molecular memory might be especially suited for primary storage.

12. Read the text, divide it into parts and give the title to each of them. Write a summary of the text.

Related Technologies

A secondary or tertiary storage may connect to a computer utilizing computer networks. This concept does not pertain to the primary storage, which is shared between multiple processors in a much lesser degree.

Direct-attached storage (DAS) is a traditional mass storage, that does not use any network. This is still a most popular approach. This term was coined lately, together wim NAS and SAN.

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Network-attached storage (NAS) is mass storage attached to a computer which another computer can access at file level over a lo- cal-area network, a private wide-area network, or in the case of online file storage, over the Internet.

Network computers are computers that do not contain internal mass storage devices. Instead, all data are stored exclusively on a NAS.

Storage area network (SAN) is a specialized network, that provides other computers wim storage capacity. The crucial difference between NAS and SAN is me former presents and manages file systems to client computers, whilst a latter provides access at block-addressing (raw) level, leaving it to attaching systems to manage data or file systems within the provided capacity.

Large quantities of individual magnetic tapes, and optical or mag- neto-optical discs may be stored in robotic tertiary storage devices. In tape storage field they are known as tape libraries, and in optical storage field optical jukeboxes, or optical disk libraries per analogy. Smallest forms of either technology containing just one drive device are referred to as autoloaders or autochangers.

Robotic-access storage devices may have a number of slots, each holding individual media, and usually one or more picking robots that traverse die slots and load media to built-in drives. The arrange- ment of the slots and picking devices affects performance. Important characteristics of such storage are possible expansion options: adding slots, modules, drives, robots. Tape libraries may have from 10 to more than 100,000 slots, and provide terabytes or petabytes of near- line information. Optical jukeboxes are somewhat smaller solutions, up to 1,000 slots.

Robotic storage is used for backups, and for high-capacity archives in imaging, medical, and video industries. Hierarchical storage man- agement is a most known archiving strategy of automatically migrating long-unused files from fast hard disk storage to libraries or jukeboxes. If the files are needed, they are retrieved back to disk.

In electronics, an integrated circuit (also known as 1С, micro- circuit, microchip, silicon chip, or chip) is a miniaturized electronic circuit (consisting mainly of semiconductor devices, as well as pas- sive components) tfiat has been manufactured in the surface of a thin substrate of semiconductor material.

A hybrid integrated circuit is a miniaturized electronic circuit constructed of individual semiconductor devices, as well as passive components, bonded to a substrate or circuit board.

traverse; substrate

13. Translate the text without a dictionary.

Компьютерная память (устройство хранения информации, запоминающее устройство) — часть вычислительной машины, физическое устройство или среда для хранения данных в течение определенного времени.

Наиболее известны средства машинного хранения данных, используемые в персональных компьютерах: модули опера- тивной памяти, жесткие диски (винчестеры), дискеты (гибкие магнитные диски), CD- или DVD-диски, а также устройства флеш-памяти.

Компьютерная память обеспечивает поддержку одной из на- иважнейших функций современного компьютера — способность длительного хранения информации. Вместе с центральным про- цессором запоминающее устройство являются ключевыми зве- ньями так называемой архитектуры фон Неймана — принципа, заложенного в основу большинства современных компьютеров общего назначения.

Система хранения информации в современном цифровом компьютере основана на двоичной системе счисления. Числа, текстовая информация, изображения, звук, видео и другие формы данных представляются в виде последовательностей битовых строк или бинарных чисел, каждое из которых состоит из значений 0 и 1. Это позволяет компьютеру легко манипули- ровать ими при условии достаточной ёмкости системы хране- ния. Например, для хранения небольшого рассказа достаточно иметь устройство памяти общим объемом всего лишь около 8 миллионов бит (примерно 1 мегабайт).

К настоящему времени создано множество разнообразных устройств, предназначенных для хранения данных, многие из которых основаны на использовании самых разных физических эффектов. Универсального решения не существует, каждое содержит те или иные недостатки. Поэтому компьютерные

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системы обычно оснащаются несколькими видами систем хранения, основные свойства которых обусловливают их ис- пользование и назначение.

В зависимости от назначения и особенностей реализации устройств компьютерной памяти, по-разному подходят и к вопросам их классификации.

Так, при рассмотрении удаленности и доступности памяти для центрального процессорного устройства различают первич- ную, вторичную или третичную память.

В зависимости от возможности записи и перезаписи данных, устройства памяти подразделяются на следующие типы:

запоминающее устройство с записью-считыванием (англ. read-write memory);

постоянное запоминающее устройство;

программируемое постоянное запоминающее устройство.

По энергозависимости:

энергонезависимая память;

энергозависимая память (к этому типу памяти относятся ОЗУ, кэш-память);

динамическая память;

статическая память.

По виду физического носителя и принципа работы:

акустическая память;

голографическая память;

емкостная память;

криогенная память;

лазерная память;

магнитная память;

молекулярная память;

полупроводниковая память;

фазоинверсная память;

электростатическая память.

14. Talking points:

1. Computer data storage: its definition and purpose.

2. Hierarchy of storage.

3. Characteristics of storage.

4. Fundamental storage technologies.

5. Related technologies.

удаленность — remoteness; акустический — acoustic; емкост- ный — capacitor; криогенный — cryogenic; молекулярный — molecular; фазоинверсный — Phase Change Rewritable, PCR; электростатический — electrostatic

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