ASCII data formats to show data in computer.

1. 2. Data Formats
Data Representation
Introduction to Information Technologies

2. Introduction
• Examples
Computer
Real World
Data
Input device
Data
Dear Mom:
Keyboard
10110010…
Digital
camera
10110010…
pp. 59.-61
Data Representation
Introduction to Information Technologies

3. Format must be appropriate
• The internal representation must be
appropriate for the type of processing to
take place (e.g., text, images, sound)
Data Representation
Introduction to Information Technologies

4. Standards Organizations
• ISO – International Standards Organization
• CSA – Canadian Standards Association
• ANSI – American National Standards
Institute
• IEEE – Institute for Electrical and
Electronics Engineers
• Etc.
Data Representation
Introduction to Information Technologies

5. Examples of Standards
Type of Data
Alphanumeric
Standards
ASCII, EBCDIC, Unicode
Image
JPEG, GIF, PCX, TIFF
Motion picture
MPEG-2, Quick Time
Sound
Sound Blaster, WAV, AU
Outline graphics/fonts
PostScript, TrueType, PDF
Data Representation
Introduction to Information Technologies

6. The Problem
• Representing text strings, such as
“Hello, world”, in a computer
Data Representation
Introduction to Information Technologies

7. Codes and Characters
• Each character is coded as a byte
• Most common coding system is ASCII
(Pronounced ass-key)
• ASCII = American National Standard
Code for Information Interchange
Data Representation
Introduction to Information Technologies

8. ASCII Features
•
•
•
•
7-bit code
8th bit is unused (or used for a parity bit)
27 = 128 codes
Two general types of codes:
– 95 are “Graphic” codes (displayable on a
console)
– 33 are “Control” codes (control features of the
console or communications channel)
Data Representation
Introduction to Information Technologies

9. ASCII Chart
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
NULL
SOH
STX
ETX
EDT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI
Data Representation
001
DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US
010
!
"
#
$
%
&
'
(
)
*
+
,
.
/
011
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
100
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
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c
d
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111
p
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DEL
Introduction to Information Technologies

10. 0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
NULL
SOH
STX
ETX
EDT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI
Data Representation
001
DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
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SUB
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"
#
$
%
&
'
(
)
*
+
,
.
/
011
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
100
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
b
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d
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~
DEL
Introduction to Information Technologies

11. 0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
Least
1100
1101
1110
1111
000
001
010
011
NULL
DLE
0
SOH
DC1
!
1
STX
DC2
"
2
ETX
DC3
#
3
EDT
DC4 Most significant
$
4
ENQ
NAK
%
5
ACK
SYN
&
6
BEL
ETB
'
7
BS
CAN
(
8
HT
EM
)
9
LF
SUB
*
:
VT
ESC
+
;
significant bit
FF
FS
,
<
CR
GS
=
SO
RS
.
>
SI
US
/
?
Data Representation
100
@
A
B
C
bit D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
b
c
d
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f
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p
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DEL
Introduction to Information Technologies

12. e.g., ‘a’ = 1100001
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
NULL
SOH
STX
ETX
EDT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI
Data Representation
001
DLE
DC1
DC2
DC3
DC4
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SYN
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CAN
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SUB
ESC
FS
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"
#
$
%
&
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(
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*
+
,
.
/
011
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
100
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
b
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d
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f
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m
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111
p
q
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x
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~
DEL
Introduction to Information Technologies

13. 95 Graphic codes
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
NULL
SOH
STX
ETX
EDT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI
Data Representation
001
DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US
010
!
"
#
$
%
&
'
(
)
*
+
,
.
/
011
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
100
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
b
c
d
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f
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k
l
m
n
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111
p
q
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x
y
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{
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~
DEL
Introduction to Information Technologies

14. 33 Control codes
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
NULL
SOH
STX
ETX
EDT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI
Data Representation
001
DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US
010
!
"
#
$
%
&
'
(
)
*
+
,
.
/
011
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
100
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
111
p
q
r
s
t
u
v
w
x
y
z
{
|
}
~
DEL
Introduction to Information Technologies

15. Alphabetic codes
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
NULL
SOH
STX
ETX
EDT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI
Data Representation
001
DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US
010
!
"
#
$
%
&
'
(
)
*
+
,
.
/
011
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
100
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
111
p
q
r
s
t
u
v
w
x
y
z
{
|
}
~
DEL
Introduction to Information Technologies

16. Numeric codes
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
NULL
SOH
STX
ETX
EDT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI
Data Representation
001
DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US
010
!
"
#
$
%
&
'
(
)
*
+
,
.
/
011
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
100
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
111
p
q
r
s
t
u
v
w
x
y
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{
|
}
~
DEL
Introduction to Information Technologies

17. Punctuation, etc.
0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
NULL
SOH
STX
ETX
EDT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI
Data Representation
001
DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US
010
!
"
#
$
%
&
'
(
)
*
+
,
.
/
011
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
100
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
111
p
q
r
s
t
u
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x
y
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{
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}
~
DEL
Introduction to Information Technologies

18. “Hello, world” Example
H
e
l
l
o
,
w
o
r
l
d
=
=
=
=
=
=
=
=
=
=
=
=
Data Representation
Binary
01001000
01100101
01101100
01101100
01101111
00101100
00100000
01110111
01100111
01110010
01101100
01100100
=
=
=
=
=
=
=
=
=
=
=
=
Hexadecimal
48
65
6C
6C
6F
2C
20
77
67
72
6C
64
=
=
=
=
=
=
=
=
=
=
=
=
Decimal
72
101
108
108
111
44
32
119
103
114
108
100
Introduction to Information Technologies

19. Common Control Codes
•
•
•
•
•
CR
LF
HT
DEL
NULL
0D
0A
09
7F
00
carriage return
line feed
horizontal tab
delete
null
Hexadecimal code
Data Representation
Introduction to Information Technologies

20. 0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
NULL
SOH
STX
ETX
EDT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI
Data Representation
001
DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US
010
!
"
#
$
%
&
'
(
)
*
+
,
.
/
011
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
100
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
111
p
q
r
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x
y
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{
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}
~
DEL
Introduction to Information Technologies

21. Terminology
• Learn the names of the special symbols
–
–
–
–
–
–
[]
{}
()
@
&
~
Data Representation
brackets
braces
parentheses
commercial ‘at’ sign
ampersand
tilde
Introduction to Information Technologies

22. 0000
0001
0010
0011
0100
0101
0110
0111
1000
1001
1010
1011
1100
1101
1110
1111
000
NULL
SOH
STX
ETX
EDT
ENQ
ACK
BEL
BS
HT
LF
VT
FF
CR
SO
SI
Data Representation
001
DLE
DC1
DC2
DC3
DC4
NAK
SYN
ETB
CAN
EM
SUB
ESC
FS
GS
RS
US
010
!
"
#
$
%
&
'
(
)
*
+
,
.
/
011
0
1
2
3
4
5
6
7
8
9
:
;
<
=
>
?
100
@
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
101
P
Q
R
S
T
U
V
W
X
Y
Z
[
]
^
_
110
`
a
b
c
d
e
f
g
h
i
j
k
l
m
n
o
111
p
q
r
s
t
u
v
w
x
y
z
{
|
}
~
DEL
Introduction to Information Technologies

23. Escape Sequences
• Extend the capability of the ASCII code set
• For controlling terminals and formatting output
• Defined by ANSI in documents X3.41-1974 and
X3.64-1977
• The escape code is ESC = 1B16
• An escape sequence begins with two codes:
ESC
[
1B16
Data Representation
5B16
Introduction to Information Technologies

24. Data Representation
Introduction to Information Technologies

25. Thank you
Data Representation
Introduction to Information Technologies