Task. Read and translate the text. Make a plan.

Itis interesting to note that memory, one of the basic com­ponents of the computer, is often called storage. It stores cal­culation program, the calculation formulae, initial data, inter­mediate and final results. Therefore, the functions of the computer memory may be classified in the following way. Firstly, the computer memory must store the information transmitted from the input and other devices. Secondly, memory should produce the information needed for the computation process to all other devices of the computer.

Generally, memory consists of two main parts called the main, primary or internal, memory and the secondary, or ex­ternal memory. The advantage of the primary memory is an extremely high speed. The secondary memory has a compara­tively low speed, but it is capable of storing far greater amount of information than the main memory. The primary storage takes a direct part in the computational process. The second­ary storage provides the information necessary for a single step in the sequence of computation steps.

The most important performance characteristics of a stor­age unit are speed, capacity and reliability. Its speed is measured in cycle time. Its capacity is measured by the number of ma­chine words or binary digits. Its reliability is measured by the number of failures (отказ) per unit of time.

План в вопросной форме.

1. What is memory?

2. What is the function of memory?

3. What are the main parts of memory?

4. What are advantages and disadvantages of a storage unit?

5. What are their functions?

6. What are performance characteristics of the main and secondary memory?

7. What units are performance characteristics measured by?

План в назывной форме

1. The definition of memory.

2. The main functions of memory.

3. Classification of memory.

4. Advantages and disadvantages of memory components.

5. The functions of memory components.

6. Performance characteristics of memory.

7. The units for measuring the performance characteristics of memory.

План в тезисной форме.

1. Memory is one of the basic components of the compu­ter.

2. Memory stores initial data, intermediate and final results.

3. It produces the information needed to other devices of the computer.

4. Memory consists of the main (internal) and the second­ary (external) storage.

5. The main memory has high speed, but small capacity; the secondary memory possesses lower speed but greater ca­pacity.

6. The main memory performs computation; the secondary memory provides information sequentially, step by step.

7. The performance characteristics— speed, capacity and reliability — are measured by cycles, binary digits and the number of failures per unit of time.

Text 5.

What is CD-ROM?

CD-ROM is an abbreviation for Compact Disc Read-Only Memory, a type of optical disk capable storing large amounts of data — up to 1GB, although the most common size 650MB (megabytes). A single CD-ROM has e storage capacity of 700 floppy disks, enough memory to store about 0,000 text pages. CD-ROMs cannot be erased and filled with new data. To read a CD, you need a CD-ROM player. All CD-ROMs have a standard size and for-at, so you can load any type of CD-ROM into any CD-ROM player. In addition, CD-ROM players are capable of playing audio CDs. CD-ROMs are good to store information that requires large storage capacity.

 

Text 6.

What is a floppy disk?

 

A soft magnetic disk is called floppy because it flops if you bend it. Floppy disks (often called floppies or diskettes) have less storage capacity than hard disks but you can remove them from a disk drive and they are portable. Disk drives for floppy disks are called floppy drives.

Most common floppies come in size 3,5-Inch. They have a rigid plastic envelope. Despite their small size, floppies have a large storage capacity — from 400K to 1.4MB of data. The most common sizes for PCs are 1.44MB (high-density).

 

 

Tests.

Test 1.

1. The time required for the computer to locate and transfer data in the storage device is called the data …time.

a) sequence; b) access; c) value.

2. … memories have no moving parts.

a) electronic; b) mechanical; c) electromechanical.

3. Magnetic …were the main elements used for pri­mary memory in digital computers for many years.

a) cores; b) tapes; c) disks.

4. … is more commonly used for memory at present.

a) bipolar semiconductor; b) MOS; c) field-effect tran­sistor.

5. Magnetic disks constitute the … storage media.

a) internal; b) primary; c) secondary.

6. Data are stored in … codes in primary as well as in secondary storage.

a) digital; b) binary; c) numerical.

7. Data access time is … in electronic memories than that in electromechanical memories.

a) longer; b) much longer; c) shorter.

8. Electronic memories have … capacities for data storage.

a) more; b) larger; c) less.

Test 2.

1. Primary

2. Secondary

3. Magnetic disc

4. Binary cods

5. RAM

6. Bit

7. Byte

8. ROM

9. Floppy

10. Capacity

 

a) one of the performance characteris­tics of storage measured in binary digits;

b) memory that has random access to the information;

c) combination of units of information;

d) the main method of secondary stor­age performing both sequential and random storage;

e)the principal flexible second storage circuit element;

f) part of memory having lower speed but greater capacity;

g) a unit of information or binary digit;

h) the most expensive part of memory having the least capacity and the fast­est access time;

i) area of memory where protected programs can be read from but not written on;

j) a fixed number of consecutive bits representing a character.

Unit VIII.

Central processing unit.

Text 1.

Central processing unit.