Transcript ภาพนิ่ง 1

Introduction to Computers…
• We will learn :
• Components of Computer: Hardware
vs Software.
• Components of Hardware: CPU,
Memory, Storage, Input/Output
Devices.
• Components of Software: Operating
System and Application Programs.
• STORAGE structure.
1
The Big Picture
A computer system contains:
• hardware
(equipment)
• software
(programs)
• people
(programmers and
end-users)
2
Hardware: The Physical
Components of a Computer
Secondary
storage
device
data stores
and
programs
Input
device
Sends
data to
the
central
processi
ng
unit
Input
Secondary
storage
Central
processing
unit (CPU)
executes
computer
instructions
memory
data and holds
programs
temporarily
Process
Output
device
makes
processed
data
(informati
on)
available
Output
3
A computer is a machine that can
be programmed to
• accept data
• process it into useful information
• store it away for safekeeping and later
use
4
Processing Unit
Processing Unit is composed of
• Central Processing
Unit (CPU) that
executes program.
• Main Memory that
stores program and
data.
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6
Main Memory: Structure
• Ordered sequence of
storage locations called
memory cells.
• Each memory cell is
identified by a unique
address.
• The data stored in a
memory cell is its
content.
• One can either read a
memory cell or write to a
memory cell.
7
Main Memory: Data
Representation in Memory Cells
• Data represented as binary
numbers (i.e. base 2)
which are collections of 1s and
0s.
• Here 1 and 0 correspond to
two different levels
of voltage in electrical
implementation of the
memory. For example: 0 0
Volts
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Main Memory: Operatio
REA
D
CP
U
WRIT
E
CP
U
Addr
essData
MEMO
RY
Addr
ess
Data
MEMO
RY
9
Main Memory: Memory Sizes
1 byte = 8 bits.
10
1 kilobyte = 2 or 1024 bytes.
1 Megabyte = 220 or
1,0548,786 bytes.
30
1 Gigabyte = 2 or
1,073,741,824 bytes.
Typical PC Main Memory is
10
Storage
• Primary storage (or memory)
holds
programs and data
temporarily: Main Memory.
• Secondary storage devices
such as disks
store data and programs.
11
Secondary Storage
• Secondary storage has more
size than Main
Memory (i.e. Primary
Memory).
• It is non-volatile, when you
power down the
computer data is not lost.
• We use secondary storage to
store our
programs and data that we
want to save.
12
Software:
Telling the Machine What to
Do
• Software - the planned, stepby-step set of
instructions required to turn
data into information.
• Divided principally into
systems and applications.
13
•
•
•
•
Hardware & Software:
Structure
Hardware
Operating System
Application Programs
User
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Software: Operating System
• Controls the interaction of
the computer with its
environment (including user).
• Management of memory,
processor time and
other resources for various
tasks.
• Execute and provide services
for applications.
15
Software: Applications
Software
• Programs designed to
perform specific tasks
and functions.
Examples: Matlab,
Excel, Microsoft Word,
and many more….
• Often found in the mass
market as
• packaged software or
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Software: Organization
(Files, Folders, Drives, Path)
• Your computer’s filing system
has three basic
divisions: files, folders and
drives
• Everything saved on your
computer is stored as a file
• You can store a file in a
folder (called “directory” under
UNIX), and in turn store that
folder inside another folder.
Your computer also stores files
in folders. When computer
needs one of those files, it
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Software Organization
Disk
Drive
Files
Fold
ers
Files
Fold
ers
Files
Fold
ers
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Software:Organization
Examples
• Disk Drives under My
Computer (Windows)
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Software: Organization
Examples
• Example CD-ROM Drive
Contents: Files and
Folders
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Software : Organization
Examples
• Example Folder (A folder of
the CD-ROM in the
previous slide.)
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Programming Languages
• A programming language is
a set of rules that
provides a way of telling a
computer what
operations to perform.
• There are several levels (or
“generations”) of
programming languages:
• High-level
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High-Level Language
• High-level languages use
English-like words
that are much easier for
humans to understand.
• A translator is needed to
convert the high-level
language into machine
language that computers
understand.
• There are several languages
that you can use
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Assembly Language
• Assembly languages are
written using
mnemonic codes and
assemblers replace
mnemonic codes with 0s and
1s to create
machine code.
• Since machine language is
the only language
the computer can execute,
25
Machine Language
• This is the lowest level of
programming
language because it
represents data and
program instructions as 0s
and 1s.
• All programs written in
different programming
languages are eventually
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Example for a = a + b
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Compiler, linker,
Source
File loader…
Comp
(Text)
iler
Libra
Other
Object
ry
Files
(binary)
Object
File
(binary)
Linker
Executable
File
(binary)
Loa
der
Inpu
t
Resu
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