HOW CAPACITY IS EXPRESSED?

HOW CAPACITY IS EXPRESSED?

In a computer system, data is represented using the binary system.  Combinations of binary digits (bits).  They are only two binary digits.

  1 (“on”)   and  0(“off”)

These digits can be arranged in such a way that they represent characters, digits and other values.

(a)    Bit. This is the smallest unit of measurement of information.  In binary system each 0 or 1 is called a bit, which is a short form for a binary digit.

(b)   Byte. A group of 8 bits is called a byte and a byte represents one character, digit but the figure is commonly rounded.

(c)    A Kilo Byte. (KB) is about 100bytes (1024 bytes)

(d)   A Mega byte:  (MB) is about 1 million bytes (1,048,576 bytes)

(e)    A Giga byte: (GB) is about 1 billion bytes. (1,073,741,824 bytes)

(f)    A Tera byte (TB) is about 1 trillion bytes (1, 009, 511, 627,  776)

Summary:

Unit	Abbreviation	Exact amount (Bytes)	Approximate no. of pages of text
Kilobyte Megabyte Gigabyte Terabyte	KB MB GB TB	1,024 1,O48,576 1, 073, 741,824 1, 099,511,627,776	½ 500 500,000 500,000,000

            A byte is eight bits grouped together as a unit, and provides enough

 different combinations of 0_s and 1_s to represent 2⁸ = 256 individual

 characters that include numbers, letters and symbols.

            A byte is the basic storage unit in memory and each byte is placed in a

precise location in memory called an address.

BINARY CODING SYSTEM

 Letters, numbers and special characters are represented with in a computer system by means of binary coding schemes i.e off/on 0_s and 1_s are arranged in such away that they can be made to represent characters, digits and other values.  Two binary coding schemes are:

(a)    ASCII (American Standard Code for information interchange)

(b)   EBCDIC (Extended Binary Coded Decimal Interchange Code)

ASCII is typically used to represent data for microcomputers, and EBCCDIC is used on larger computers.