Magnetic Bubbles

The physical feasibility of magnetic bubbles has been proved. Bubbles can be created and destroyed, moved reversibly in two dimensions, magnetized for presence or absence of charge, and mutually repulsed to perform logic.

Micro-sized bubbles can be supported in magnetic rare earth garnets grown epitaxially on nonmagnetic matching substrates. Since the number of similar process strips is much fewer than for silicon, the cost per area should be lower. Shift registers 1000 bits long, at densities of 1.6M bits/in², should be routine. Mask size, not defect density, is the present size limitation.

Electron beam processing should benefit bubble technology: smaller bubbles for higher packing densities and lower costs should result.

Проверьте, знаете ли вы следующие термины.

6.13. Переведите данные термины:

1. add-on memory, 2. backing memory, 3. bubble memory, cache memory, 4. CCD memory, 5. content-addressable memory, 6. destructive memory, 7. erasable memory, 8. read-only memory, 9. general purpose memory, 10. high-density memory, 11. high­speed memory, 12. mass (storage) memory, 13. metal-electric-semiconductor memory; 14. off-chip memory, 15. on-chip mem­ory, 16. power-down memory, 17. scratch-pad memory; 18. self-refreshing memory

6.14. Расшифруйте следующие сокращения:

ROM, RAM, PROM, EPROM, EEPROM

МАТЕРИАЛЫ ДЛЯ РАБОТЫ В АУДИТОРИИ

(ЗАНЯТИЕ ВТОРОЕ)

Проверьте домашнее задание.

6.15. Ответьте развернуто на следующие вопросы:

1. What are the most important characteristics of memory? 2. What do you know about different types of memories? 3. What do you know about analogue and digital recording? 4. Can you com­pare random access memories and serial access memories? 5. What developments can be expected by the end of the century in the field of computer memories? 6. What is being done at present to improve memory capacity and speed?

Определите контекстуальное значение выделенных слов.

6.16. Переведите, обращая внимание на значение слова challenge:

1. Established ways of design and fabrication are being chal­lenged today by newer techniques. 2. Since the early days of sili­con technology, contacts between metal and silicon have pre­sented a constant challenge to the electronics industry. 3. Tech­nological breakthroughs are necessary to meet the challenges of programmable microelectronic products. 4. By far the greatest challenge in the language area will be to develop new and more powerful general-purpose languages. 5. Typical challenges include checking out and operating complex missile systems. 6. The chal­lenge was to do the test carefully.

Учитесь читать и переводить.

Текст 6.6. Прочитайте текст. Определите его основную тему. Озаглавьте текст.

Josephson logic and memory circuits make use of essentially conventional passive components and a rather sophisticated active device.

The two phenomena underlying the operation of the active devices are superconductivity and electron tunneling.

The first of these, superconductivity, discovered by Kammerlingh Onnes, was explained in detail by Bardeen, Cooper, and Schrieffer. All four received Nobel prizes in physics for their work. Electron tunneling received its first practical application with the invention of the semiconductor tunnel diode by Esaki in 1957. The second important tunneling discovery was that of su­perconductive tunneling by Giaever. Lastly, Josephson predicted that magnetic field-sensitive supercurrents should flow through a tunnel junction with a frequency proportional to the voltage across the junction. The tunneling discoveries of Esaki and Giaever and V the predictions of Josephson led to a "tunneling" Nobel prize in physics, awarded hi 1973.

That the superconductive tunnel junction, combined with a means of controlling the magnitude of the zero-voltage current, forms a fast, low-power logic and memory device was recognized in 1967 by Matisoo. Matisoo designed and fabricated such devices and established their static and dynamic properties in simple cir­cuits.

Текст 6.7. Прочитайте текст. Составьте структурно-ло­гическую схему типов памяти. Используйте также инфор­мацию Основного текста.