Communications

Unit 8

A.

TEST YOURSELF

Match the following terms to the appropriate definition:

1. ___ Mass storage

2. ___ Sequential file

3. ___ Index-sequential file

4. ___ Direct-access file

5. ___ Magnetic tape

6. ___ Cartridge tape

7. ___ Backup file

8. ___ Disk

9. ___ Floppy disk

10. ___ Track density

a. A flexible disk.

b. A collection of records that can only be accessed by starting with the first record and proceeding through each record in the file.

c. A generic term for tapes and disks.

d. A file that contains an index to speed up access to records.

e. A flexible medium coated with a film on which data can be magnetically recorded.

f. A copy of a file that is made for possible later reconstruction in case the original is lost or damaged.

g. A tape designed for the purpose of making backup files.

h. A file that allows you to read or write any record in the file without regard to its location.

i. The number of tracks per inch on a disk.

j. A platter on which a magnetic or reflective coating is applied.

True/False:

11. ___ The purpose of a mass-storage device is to provide a volatile storage medium for information.

12. ___ Optical disks have not improved the capacity of mass-storage devices.

13. ___ To read or write the last record in a sequential file, you must first read or write all previous records in the file.

14. ___ A disadvantage of disk over tape is slower access time.

15. ___ A disk device can retrieve data in billionths of a second.

16. ___ Data are recorded on a spinning disk on a series of concentric tracks.

17. ___ Each disk track is divided into regions called sectors.

18. ___ By sealing the drive container, the read/write head can be made much smaller.

19. ___ Read-only optical disks are replacing microfilm for storage and retrieval of information.

20. ___ Erasable optical disks use a magnetic material on the surface of the disk.

21. ___ CD ROMs have a standard format for storing data.

1.1 Read and translate the following phrases.

The field of communications, the transmission of information, hexagonal-shaped cells, the internal combustion engine, scientific and technical research, converge computer and communication technologies, continuous smoothly varied signals, discrete on/off signals, cellular telephones, the appropriate hardware and software, a world-wide network, computer-related devices, a single entity.

1.2 Learn key words and word-combinations.

burst(n) - пакет

bus(n) - шина

bus network – магістральна мережа

circuit switching – перемикання каналів

collision(n) – колізія; конфлікт

compress(v) - ущільнювати

CSMA/CD(Carrier Sense Multiple Access with Collision Detection) – груповий доступ з контролем носія і виявленням конфліктів

data communications – передавання даних

data network – мережа даних

gateway(n) – шлюз(міжмереживний)

ISDN(Integrated Service Digital Network) - цифрова мережа інтегрованих послуг

LAN(local area network) – локальна мережа

MAN(metropolitan area network) – міжміська мережа

network(n) - мережа

packet(n) - пакет

packet switching – комутація пакетів

public voice network – мережа засобів зв‘язку

ring(n) – кільце

ring network – кільцева мережа

star topology – зіркова топологія

telecommunications – телезв’язок і дистанційне передавання даних

token(n) – естафета

token passing – естафетне передавання

upgrade (n) – нова версія

WAN(wide-area network) – міжрегіональна мережа зв‘язку

1.3 Read and translate the text.

Дата добавления: 2015-01-03