Basic
units of data storage;
The basic
and smallest unit of computer memory is called bit that stands for binary
digit.
Computer
represents data in the form of binary
zeros and ones,
These bits
are primary sources of such representations. A bit may have two possible states
ie.,0 or 1.
0 used for
circuit off whereas 1 is used circuit on. Thus a single bit may have two
possible representations of data 0 and 1.some other units of computer memory
are given below;
Nibble;
One nibble
is the combination of 4 bits . it can have 16 possible representation of data.
An example
is the hexadecimal number system, which is composed of number form 0 ie.,0000
to F i.e., 1111.
Byte
:
A byte may
be defined as “the memory required to store a single alphanumeric character of data.”
Here alphanumeric character may be any digit form 0,1,2,3……9 or an alphabet
form a to z or A to Z or any other special symbol like , : ; / ?- + *etc. a
byte is a combination of 8 bits or 2 nibble.
as a single bit can have two possible representation i.e., 0 and 1,therefore
a byte i.e., a combination of 8 bits can have 256 possible representation of
data in the form 0 and 1.
Some
commercial units of data storage that are composed of bytes are described in
the table below;
|
Name of units
|
Abbreviation
|
Number of bytes
|
|
Kilo byte
Mega byte
Giga byte
Tera byte
|
Kb
Mb
Gb
Tb
|
(2)power 10
(2)power 20
(2)power 40
(2)power 80
|
Word:
A word is a
combination of 2 bytes. some machine instruction needed computer words
comprising 16 bits. The large units that are composed of words are described in
the table below;
|
Name of units
|
Abbreviation
|
Number of words
|
Number of bytes
|
|
Double word
Quad word
Double quad word
|
DW
QW
DQ
|
2
4
8
|
4
8
16
|
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