Read the text and make up a dialogue. The Storage Unit

(1) A computer must have a way of storing information. The part of a digital computer which stores information is called storage or memory. The storage unit provides both data and instructions at the rapid rate and it accepts results that have been computed by the arithmetic unit.

(2) One of the most important characteristics of memory in a computer is the time required tо read a desired piece of information out of it. This time is called access time. It usually amounts to a few millionths of a second or less in modern fast computers. According to the access time memory may be of two or three kinds: rapid memory or addressed memory, with very fast access; slow memory for which access is relatively slow and, in some computers, intermediate memory for which the access time is in between. The second characteristic of memory is its capacity. The biggest pre­sent-day computers have memory with more than 1,0000000 registers, in each of these registers a machine word (12 decimal digits or 60 binary digits) is stored, available on call in about 2 microseconds. There are many different memory devices: magnetic tape, magnetic drums, magnetic discs, thin films, magnetic cores, etc.

(3) Magnetic drum An early high-speed, direct access storage device that used a magnetic-coated cylinder with tracks around its circumference. Each track had its own read/ write head. A magnetic drum is a rapidly rotating cylinder with thin magnetic coating on which information is stored on pa­rallel recording tracks. The information is written and read by means of magnetic heads, each track of the drum having its own head. Drums are serial access memory. They have large capacity and serve either as the main store or as a standby store.

(4) Magnetic tape is a tape made of paper or metal, or plastic which is coated with magnetic material on which infor­mation is stored as multiple polarized spots. A powerful computer may have about 100 reels of magnetic tape, each reel containing from 1 to 10 million machine words. Magnetic tape memory is a random-access memory and is usually used as an external memory.

(5) Thin film A microscopically thin layer of semiconductor or magnetic material that is deposited onto a metal, ceramic or semiconductor base. For example, the layers that make up a chip and the surface coating on high-density magnetic disks are called thin films.

(6)Magnetic disk A reusable, magnetically charged disk on which computer data is stored. This is the basis of the hard disk and floppy disk.

6.20 А) Give Russian equivalents to the following.

Fort storage /access /access time /cycle time /amount to /millionths of a second /fast computer /addressed memory /in between /decimal digit /binary digit /avai­lable /on call /thin film magnetic core /recording tracks /inter­nal memory /long-time memory /standby memory.

b) Find the English equivalents the following in the text above.

Способ напоминания информации /адресная пеня /доступ / выборка /время выборки /емкость /двоичный знак /десятичный знак /имеющийся /по вызову /тонкая пленка /дорожка /магнитная головка.

c) Give English equivalents for: ¹/₁₀, ¹/₃, ¹/₇, ¹/₁₀₀, ³/₅, ²/₇, 0,001; сотая доля секунды, тысячная доля секунды, миллионная доля секунды, 2 в десятой степени.