Page 166 - FUNDAMENTALS OF COMPUTER

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166 Fundamentals of Computers NPP

codes are used to provide any control informa- go H$åß`yQ>a H$mo {Z`§ÌU g§~§Yr OmZH$mar àXmZ H$s OmVr
tion to the computer system. For example, end h¡Ÿ& CXmhaUV, end of line, end of page, start of
of line, end of page, start of text, end of text,
carriage return etc. are non-printable control text, carriage return Am{XŸ& ASCII H$moS> H$m Cn`moJ
characters coded by the ASCII code. These codes {à¨Q>a, Q>a{_Zb VWm H$s-~moS>© _| {H$`m OmVm h¡ Ÿ& O¡go
are extensively used by printers, terminals and O~ h_ {H$gr ASCII H$s~moS>© _| ‘A’ H$m ~Q>Z X~mVo h¢
keyboard. When we type ‘A’ on the keyboard a
7 bit code enters inside the computer circuit : Vmo H$åß`yQ>a _| {ZåZ 7-{~Q>m| H$s ~mBZar g§»`m H$s~moS>©
1000001 go àdoe H$aVr h¡ … 1000001
Consider the following character string and {ZåZ Ho$aoŠQ>am| H$s l¥§Ibm H$mo XoImo…
the corresponding ASCII code:
H I FI H I FI
This string has five characters: Bg_| nm±M Ho$aoŠQ>a h¢…

H, I, SPACE, F and I. H, I, SPACE, F and I.
Therefore 5 × 7 = 35 bits will needed in AV… Bg l¥§Ibm H$mo àX{e©V H$aZo hoVw H$åß`yQ>a _|
computers to represent this characters string. 5 × 7 = 35 {~Q>m| H$m Cn`moJ {H$`m OmEJm Ÿ&
Since total 128 character codes are possible My±{H$ Hw$b 128 Ho$aoŠQ>a H$moS> hmoVo h¢, AV… BZH$s
for a 7 bit ASCII. Therefore the range of ASCII {d{^ÝZ g§»`m nÕ{V`m| _| gr_mE± Ü`mZ aIZm _hËdnyU©
values in various number system can be as
follows: hmoJm
Decimal → 0 to 127, Binary → 0000000 to Xe_bd _|→0 go 127 VH$, ~mBZar _| →
1111111, Octal → 000 to 177, 0000000 go 1111111 VH$, Am°ŠQ>b _| → 000
go 177 VH$,
Hexadecimal → 00 to 7F hoŠgmS>o{g_b _| → 00 go 7F VH$
Nowadays 8-bit ASCII or extended ASCII AmOH$c 8-{~Q> ASCII `m EŠñQ>|S>oS> ASCII
is popular.
àM{cV h¡Ÿ&
3.9 EBCDIC Code 3.9 EBCDIC H$moS>
EBCDIC stands for Extended Binary Bggo VmËn`© h¡ EŠgQ>|S>oS> ~mBZar H$moS>oS> S>o{g_c
Coded Decimal Interchange Code. This code B§Q>aM|O H$moS> & `h ^r EH$ Ho$aoŠQ>a H$moS> h¡¡ {Og_|
is an alphanumeric code. It uses 8-bits to code
the characters. Thus, it has 256 (2 ) character àË`oH$ Ho$aoŠQ>a H$mo 8-{~Q>m| H$s ~mBZar g§»`m go
8
8
codes. The coding scheme for the characters is àX{e©V {H$`m OmVm h¡Ÿ& AV… Bg_| 256 (2 ) àH$ma
different from that is used in ASCII codes. Ho$ H$moS> hmoVo h¢Ÿ& bo{H$Z `o ASCII go EH$X_ {^ÝZ hmoVo
EBCDIC uses BCD codes instead of binary h¢Ÿ& BZH$mo BCD g§»`mAm| go ~Zm`m J`m h¡Ÿ& `h n§M
numbers. The entire system is similar to punch H$mS>© H$moS> Ho$ g_mZ H$m`© H$aVm h¡Ÿ& Bggo n[anW
card codes which makes the hardware very EH$X_ gab hmo OmVm h¡Ÿ& BgH$m Cn`moJ IBM Ho$ ~‹S>o
simple. This code is extensively used in IBM
Machines. H$åß`yQ>am| _| {H$`m OmVm h¡Ÿ&