Микроэлектроника настоящее и будущ

2

1. Included in this section is a description of...

2. Shown on the photo is the computer...

3. Переведите следующие речевые отрезки, содержащие инвертированные кон­струкции. Обратите внимание на языковые средства, вызывающие инверсию:

1

1. Important for the computer is the problem of information securit).

2. Fundamental to the design of computer is its size.

2

1. Of special interest are the so-called cash memories.

2. Of primary importance to science are the advances in computer developments.

4. Переведите следующие речевые отрезки, содержащие инвертированные кон­струкции. Обратите внимание на союзы as и though, стоящие после прилага­тельных. Данные сочетания могут вызвать явление грамматической инвер­сии. Перевод обычно начинается с союза, имеющего значение «хотя» в данном случае, затем переводится подлежащее (N¹).

1. Useful as electron tubes were, they are not used at present.

2. Uncertain though the information was, it was quite useful.

Основной текст

1. Переведите устно с листа первую часть текста (I). Работа выполняется под руководством преподавателя.

2. Перевод второй части текста (II) выполняется письменно как домашнее за­дание.

3. Ознакомьтесь с терминами первой части основного текста.

nanosecond — наносекунда operating instructions — рабочие инст­рукции

read/write memory — постоянная па­мять, допускающая и считывание, и запись; оперативная память storage capacity — емкость памяти access time — время доступа cycle time — время цикла

storage location — ячейка памяти data transfer — перенос данных, пере­сылка данных random-access memory — ЗУ с произ вольной выборкой cache — кэш

serial access memory — ЗУ с последо вательным выбором buffer memory — буферная память

221

Switch device — устройство подключе­ния

funnel-junction devices — сверхпрово­дящие приборы с туннельным пе­реходом

grid of wires — сетка тонкопроводящих дорожек address bus — адресная шина instance — экземпляр объекта

New Developments in Electronic Memories

1. The versatile capabilities that have made the computer the great success of our age are due to exploitation of the high speed of electronic computation by means of stored programs. This process requires that intermediate results be stored rapidly and furnished¹ on demand for long computations, for which high speed is worthwhile² in the first place.

Memory is the predominant computer subsystem. It is a critical³ element to consider in the integration of a system.

Once prepared, a program can be reused any number of times which involves remembering and retrieving⁴ (recalling), for which high speed is worthwhile in the first place.

Storage devices or memories must have capacities sufficient not only for intermediate results but for the input and output data and the programs.

Never before has man possessed a tool comparable to a comput­er. Today there are memories accessible in tens of nanoseconds and memories with more than a billion bits. The demand for fast access and large capacity has grown constantly.

Memory is the storage medium used to hold⁵ the system’s operat­ing⁶ instructions and the specific application programs in use.

Computers can “remember” and “recall”, and virtually unlimit­ed is the capacity of computers to remember (that is to store digital information). Associated⁷ with the capacity of remembering is the ca­pacity of recalling.

In the context of electronics, “memory” (or, in British usage, “store”) usually refers to a device for storing information. Storage (“write”) and retrieval (“read”) operations are completely⁸ under electronic control.

The term “Read/Write memories” signify⁹ that they perform read and write operations at an identical¹⁰ or similar rate. Read/Write means that data is written to a bit¹¹ and then read from the bit.

Микроэлектроника настоящее и будущ

Of primary importance to characteristics for memories are stor- age capacity size, cost per bit and reliability. Other important charac teristics are speed of operation (defined in terms of access time), cy­cle ¹² time and data-transfer rate.

Access time is simply the time it takes to read or write at any stor­age location ⁿ.

The cycle time is the specified minimum period to complete read and write operations.

The data-transfer rate is the rate at which information is trans ferred to or from sequential storage positions. Most forms of memory are intended to store data temporarily.

As you can see in the diagram the CPU accesses memory accord­ing to a distinct hierarchy.

Whether it comes from permanent storage (the hard drive¹⁴) or input (the keyboard), most data goes in random access memory (RAM) first. The CPU then stores pieces of data it will need to access, often in a cache¹⁵, and maintains certain special instructions in the register¹⁶.

Random access memory (RAM) is the best known form of com­puter memory. RAM is considered “random access” because you can access any memory cell¹⁷ directly if you know the row¹⁸ and column that intersects¹⁹ at that cell.

The opposite of RAM is serial access memory (SAM). SAM stores data as a series of memory cells that can only be accessed sequential­ly ²⁰ (like a cassette tape). If the data is not in the current²¹ location, each memory cell is checked until the needed data is found. SAM works very well for memory buffers²².

A computer’s system RAM alone is not fast enough to match²' the speed of the CPU. That is why you need a cache.

At present, the smallest block of information accessible in a mem­ory system can be a single bit (represented²⁴ by 0 or 1), a larger group of bits such as a byte or character²⁵ (usually eight or nine bits), or a word (16 to 128 bits depending on the particular system). Most mem­ories are location-addressable²⁶, which means that a desired bit, byte or word has a specified address or physical location to which it is as­signed²⁷.

Semiconductor memories are extremely versatile and highly com­patible²⁸ with other electronic devices in both small and large systems

223

Input Sources

Mouse

Removable

Media

Scanner/

Camera/

Micf

Video

Other

Sources

HP announced²⁹ dramatic³⁰ new breakthrough in molecular elec­tronics.

Quantum Science Research group created the highest density elec­tronically addressable circuit, a 128-bit memory using molecular switches as active devices, which fits³¹ inside a square micron — an area so tiny (маленькая) that more than 1,000 of these circuits could be on the end of a single strand (прядь) of a human hair. The bit den­sity of the device is more than 10 times greater than today’s silicon memory chips. For the first time, they combined both memory and logic using rewritable non-volatile³² molecular-switch devices and fab­ricated the circuits using an advanced system of manufacturing called nano-imprint lithography.

“Wfe believe molecular electronics will push advances in future computer technology far beyond the limits of silicon,” said Williams,

Микроэлектроника настоящее и будут

without the need for complex and expensive changes to the base tech nology.” The problem that computer designers face is that memory that can keep up³³ with a 1 gigahertz CPU is extremely expensive. Com puter designers have solved the cost problem by “tiering^34,7 in memory using expensive memory in small quantities and then backing it up with larger quantities of less expensive memory.

2. Of prime interest to a reader will be the knowledge of the development of memories.

One of the first electronic memories was a circulating delay line a signal transmission device in which the output, properly amplified and shaped, was fed back into the input. Although it was economical it had the inherent³⁸ drawback³⁹ of serial access: the greater the capac­ity, the longer the average access time. What was really needed was selective⁴⁰ access to any stored data in a time that was both as short as possible and independent of the data address or any previous access. This is known as random access, so named to emphasize⁴¹ the total freedom of accessing and therefore of branching⁴² (following one or another part of a program). The first random-access memories (RAMs) were electrostatic storage tubes⁴³.

In the early 1950’s the core memory⁴⁴ replaced these early devic­es, providing a solution to the need for random access that truly fired the emerging computer industry.

The core memory has become the main internal computer mem­ory and was used universally until challenged by semiconductor mem­ories. Typical are memories with 1 million words (or 30 to 60 bits each)» randomly accessible in 1 microsecond. The core memory has also been extended to very large capacities, of the order of 100 million words

In the 1950’sand 1960’s electronic memories were arrays of cores, or rings, of ferrite material a millimeter or less in diameter, strung⁴ b> thousands on a grid⁴⁶ of wires. Ferrite-core memories have now been largely succeeded⁴⁷ in new designs by semiconductor memories that provide faster data access, smaller physical size and lower power con­sumption, and all at significantly lower cost.

In the early 1970’s semiconductor memory cells that served the same purpose as cores were developed, and integrated memory cif' cuits began to be installed as the main computer memory.