Texts and exercises on information science. Мартынов О.В. - 22 стр.

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43
3. Internet Video conferencing programs enable users to talk to and
see each other, …, and collaborate.
4. Networks on different continents can also … satellites.
5. For long-distance or, … computers are usually connected into a
wide area network to form a … .
6. The Web is one of the best resources for … .
7. With a few touches at a keyboard a person can … to materials in
almost everywhere.
IX. Translate:
1. The Internet is a magnificent global network with millions and
millions of computers and people connected to one another where each day
people worldwide exchange an immeasurable amount of information,
electronic mail, news, resources and, more important, ideas.
2. Hypertext is the text that contains links to other documents.
3. Internet Video conferencing programs enable users to talk to and
see each other, exchange textual and graphical information, and
collaborate.
4. The next generation of Internet-enabled televisions will
incorporate a smart-card for home shopping, banking and other
interactive services.
5. Computers are connected by means of a modem to ordinary
telephone lines or fibre-optic cables, which are linked to a dish aerial.
X. Translate:
1. Почти все о нем слышали и им пользуется все большее число
людей.
2. Сеть является одним из лучших источников информации.
3. Сеть основана на системе гипертекстов, при помощи которой
можно перемещаться по сети.
4. Интернет представляет собой отличный пример глобальной
сети.
5. Компьютеры соединены при помощи модема
с телефонными
проводами или оптико-волоконными кабелями, которые в свою
очередь подключены к параболическим антеннам.
XI. Give summary of the above text.
44
TEXT 15
Optical Disks and Drives
Optical disks can store information at much higher densities than
magnetic disks. Thus, they are ideal for multimedia applications where
images, animation and sound occupy a lot of disk space. Besides, they are
not affected by magnetic fields. This means that they are secure and stable,
e.g. they can be transported through airport metal detectors without
damaging the data. However, optical drives are slower than hard disks.
While there are hard drives with an average access time of 8 milliseconds
(ms), most CD-ROM drives have an access time of 150 to 20 ms.
There are various types of optical drives, which have become a reality.
CD-ROM systems use optical technology. The data is rewritable using a
laser beam. To read CD-ROM disks, you need an optical drive (a CD-ROM
player). A typical CD-ROM disk can hold 650 MB (megabytes) of sound,
text, photographs, music, multimedia materials and applications. In
addition, most CD-ROM drives can be used to play audio CDs. Do you
remember that CD stands for compact disk?
Yet CD-ROM technology has one disadvantage. The data on a CD-
RОМ cannot be changed or «written» to, i.e. it is impossible to add your
own material to what is on the disk. It is like a music CD. It is not designed
for you to write on, it is designed to hold a lot of information that the user
doesn't need to change.
Magneto-optical (MO) drives use both a laser and an electromagnet to
record information. Consequently, MO disks are rewritable, that is they
can be written to, erased, and then written again. They are available in two
formats. Their capacity may be more than 2 GB (gigabyte) or 230 to 640
MB. Such combined devices are good for back up purposes and storage of
large amounts of information such as a dictionary or encyclopaedia.
ASSIGNMENT TO TEXT 15.
I. Read and translate the text.
II. Answer the following questions:
1. What can optical disks be used for? 2. What are their advantages
and disadvantages? 3. How can data be retrieved from a CD? 4. What are
CDs designed for and their disadvantage? 5. What is the other type of
disks and what is their capacity?

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