Information Technology Reference
In-Depth Information
EBCDIC
Although IBM cooperated in the development of the ASCII code, it focused much of
its attention and energy on the development and use of EBCDIC. At this time, many
companies used punch cards to store much of their data, so one of the design fea
tures of EBCDIC was to allow an efficient translation between the data saved in a
punchcard format and data stored within a computer in EBCDIC. Although EBCDIC is
often mentioned as a single coding system, in fact, several variations evolved; for ex
ample, IBM worked extensively within the international community, and so it devel
oped some 57 different national EBCDIC character sets to complement its marketing
efforts.
EBCDIC was an 8bit code, built upon an earlier 6bit code (Binary Coded Decimal
Interchange Code) that had been used on early IBM computers. EBCDIC was used exten
sively with the popular IBM System/360 machines of the 1960s, and this helped moti
vate EBCDIC's continued use for many years. IBM continued to rely on EBCDIC for its
computers until 1981, when it released the IBM PC. The IBM PC computer and operating
system made full use of ASCII instead.
To illustrate these codings, Table 21 gives the 8bit encodings
for selected letters, digits, and punctuation.
Table 2-1 EBCDIC and ASCII Codings for Several Characters
Character
EBCDIC Encoding
ASCII Encoding
A
11000001
01000001
B
11000010
01000010
C
11000011
01000011
a
10000001
01100001
b
10000010
01100010
c
10000011
01100011
0
11110000
00110000
1
11110001
00110001
2
11110010
00110011
, (comma)
01101011
00101100
(dash, hyphen)
01100000
00100101
. (period)
01001011
00101110
[ (left brace)
not available
01011011
] (right brace)
not available
01011101
