Bài giảng phần cứng hệ thống thông tin
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Chương 3
Phần cứng
Hệ Thống Thông Tin
Figure 6-1
Computer systems consist of the
following hardware components:
Computer systems consist of the
following hardware components:
Input devices accept data or commands in a form useable by computers. Data and
commands can also be sent to the processing unit; e.g., keyboards, mice, scanners,
microphone, digital camera.
Output devices display the processed information understandably and usefully; e.g.
printers, monitors, speakers.
Processing devices are contained in a computer’s system unit and are comprised of
circuitry. The main circuit board is the motherboard, with its central processing unit (CPU)
and memory.
Storage devices include secondary storage for data and programs outside the computer’s
processing unit; e.g., hard disk drives, floppy disk drives, Zip® drives, CD-ROM, CD-RW and
DVD-ROM drives. Drives read from and write to storage media (the physical material that
can store data and programs).
Communication devices provide connections between computers and communication
networks, allowing for exchange of information and data with other computers via
transmission media such as cables, telephone lines, and satellites.
Computers process data by means of
a binary system.
Computers process data by means of
a binary system.
Computers are devices powered by electricity, which has two discrete states: On or
Off.
Two digits represent these states: 0 for the electronic state of Off, and 1
representing On (the presence of an electronic charge).
To be processed, all data in a computer system (words, symbols, pictures, videos,
sounds) must be reduced to a string of binary digits. (The process of converting
data from other formats into binary digits is called digitization.)
A binary digit 1 or 0 is called a bit, the smallest unit of data in a computer system.
Eight bits grouped together as a unit are called a byte, which provides enough
combinations of 0s and 1s to represent 256 individual characters, including
numbers, upper and lower case alphabet letters, punctuation marks and other
characters.
And, then what?
Coding Schemes define
the patterns of bytes
And, then what?
Coding Schemes define
the patterns of bytes
Coding schemes, such as ASCII,
EBCDIC, and Unicode, provide the
means to interact with a computer
that recognizes only bits (on/off
states).
When you press a letter on a
keyboard, the electronic signals are
converted into binary form and stored
into memory. The computer then
processes the data as bytes of
information and converts them to the
letters you see on the monitor screen
or on a printed page.
The System Unit
The System Unit
The System Unit houses
the central processing unit,
memory modules,
expansion slots, and
electronic circuitry as well
as expansion cards that are
all attached to the
motherboard; along with
disk drives, a fan or fans to
keep it cool, and the power
supply.
All other devices (monitor,
keyboard, mouse, etc., are
linked either directly or
indirectly into the system
unit.
Front of the System Unit
Front of the System Unit
Drives are housed in drive bays
which are accessed at the front of
the case.
Internal drives, such as the hard
disk drive, are installed in internal
bays that are not typically as
accessible as the external drives
pictured here.
System Unit cases come in a huge
array of types and styles,
depending upon hardware needs.
The Motherboard and CPU
The Motherboard and CPU
The motherboard is the main circuit
board of a microcomputer. It
contains the central processing unit
(CPU), the Basic Input/Output System
(BIOS), memory, mass storage
interfaces, serial and parallel ports,
expansion slots, and all the controllers
for standard peripheral devices like
the keyboard, disk drive and display
screen.
BIOS stands for
Basic Input/Output
System
. It is the lowest-level software
in the computer; it acts as an
interface between the hardware
(especially the chipset and processor)
and the operating system. The BIOS
provides access to the system
hardware and enables the creation of
the higher-level operating systems
that you use to run your applications.
The BIOS is also responsible for
allowing you to control your
computer's hardware settings, for
booting up the machine when you
turn on the power or hit the reset
button, and various other system
functions.
