Computer Engineering (English for Special Purposes). Андриенко А.С. - 40 стр.

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computer. The most common components of processing hardware are
the Central Processing Unit and main memory.
The Central Processing Unit (CPU
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) is the brain of the
computer. It reads and interprets
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software instructions and
coordinates the processing activities that must take place. The design
of the CPU affects
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the processing power and the speed of the
computer, as well as the amount
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of main memory it can use
effectively. With a well-designed CPU in your computer, you can
perform highly sophisticated
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tasks in a very short time.
Memory is the system of component of the computer in which
information is stored. There are two types of computer memory: RAM
and ROM.
RAM
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(random access memory) is the volatile
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computer
memory, used for creating loading, and running programs and for
manipulating and temporarily
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storing data;
ROM
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(read only memory) is nonvolatile, nonmodifiable
computer memory, used to hold programmed instructions to the
system.
The more memory you have in your computer, the more
operations you саn perform.
Storage hardware
The purpose of storage hardware
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is to store computer
instructions and data in a form that is relatively permanent and retrieve
when needed for processing. Storage hardware serves the same basic
functions as do office filing systems except that it stores data as
electromagnetic signals. The most common ways of storing data are
Hard disk
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, floppy disk and CD-ROM
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.
Hard disk is a rigid disk coated with magnetic material, for
storing programs and relatively large amounts of data.
Floppy disk (diskette) — thin, usually flexible plastic disk
coated with magnetic material, for storing computer data and
programs. There are two formats for floppy disks: 5.25" and 3.5". 5.25"
is not used in modern computer systems because of it relatively large
size, flexibility and small capacity
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. 3.5" disks are formatted 1.4
megabytes and are widely used.
CD-ROM (compact disc read only memory) is a compact disc
on which a large amount of digitized read-only data can be stored. CD-
ROMs are very popular now because of the growing speed which CD-
ROM drives can provide
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nowadays.
Output hardware
The purpose of output hardware
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is to provide the user with
the means to view information produced by the computer system.
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A 'more expensive alternative to the floppy disk is the
Winchester disk
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, in which the magnetic coating is applied to a rigid
aluminum platter
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. For example, a personal computer Winchester
disk unit can have such a capacity that it can transfer data faster than
a floppy disk. On the other hand, the Winchester disk is permanently
sealed in the drive unit, where as a floppy disk can be removed from
the drive and replaced by a fresh disk.
A simpler, less expensive secondary memory medium is the
audio magnetic-tape cassette. One cassette can store about as much
information as a relatively low-capacity floppy disk. The access time to
a particular address, or storage location, much longer for tape than it is
for a disk because the speed of the tape is much lower than that of a
disk and because the information is arrayed in a single linear
sequence. An important feature, of all the magnetic secondary-storage
mediums is that information is maintained even when the computer
turned off.
Vocabulary:
1. Magnetic tape - a tape with a magnetic surface on which data
can be stored by selective magnetization of portions of the
surface.
2. Magnetic disk - a flat circular plate with a magnetic surface on
which data can be stored by selective magnetization of portions
of the flat surface. The information is recorded on a series of
concentric tracks.
3. Magnetic drum - a circular cylinder with a magnetic surface on
which data can be stored by selective magnetization of portions
of the curved surface.
4. Winchester disk – жёсткий магнитный диск
5. A rigid aluminum platter – жёсткий алюминиевый диск
(пластина).
TEXT 10
Pre-reading task
Read the text “Disk Buffers” and discuss the following problems
in group:
a) In what way can a change in disk buffer size affect
disk I/O times?
b) What factors can interact to cause disk delays?

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