BIT
A bit is the smallest unit of information that can be stored or manipulated on a computer.
It consists of either zero or one. Depending on meaning, implication, or even style, it could instead be described as false/true, off/on, no/yes, and so on. We can also call a bit a binary digit, especially when working with the 0 or 1 values.
BYTE
Although computers usually provide instructions that can test and manipulate bits, they generally are designed to store data and execute instructions in bit multiples called bytes. In most computer systems, there are eight bits in a byte. The value of a bit is usually stored as either above or below a designated level of electrical charge in a single capacitor within a memory device.
A byte also happens to be how many bits are
needed to represent letters of the alphabet and other characters. For example,
the letter "A" would be 01000001; my initials
"KJW" would be010010110100101001010111. To make this a
little bit easier to see where the bytes are it is customary place a comma every four digits, to make what are sometimes
called nibbles:0100,1011,0100,1010,0101,0111.
That's not really much easier for people to read or write--and many computer
engineers, programmers, and analysts need to read and write even longer binary codes
than this.
It so happens that there are only 16 different ways to write 0's
and 1's four times. So something called hexademical code can
be used to make the numbers shorter by translating each nibble (or
half-a-byte) like this:
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Binary:
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0000
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0001
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0010
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0011
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0100
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0101
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0110
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0111
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1000
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1001
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1010
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1011
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1100
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1101
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1110
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1111
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Hexademical:
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0
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1
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2
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3
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4
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5
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6
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7
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8
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9
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A
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B
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C
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D
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E
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F
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Nibble
Half a byte (four bits) is called a nibble.
Units of Data Measurement
DIFFERENCE BETWEEN BIT AND BYTES
The terms "bits" and "bytes" are often confused and are even used interchangeably since they sound similar and are both abbreviated with the letter "B." However, when written correctly, bits are abbreviated with a lowercase "b," while bytes are abbreviated with a capital "B." It is important not to confuse these two terms, since any measurement in bytes contains eight times as many bits. For example a small textfile that is 4 KB in size contains 4,000 bytes, or 32,000 bits.
Generally, files, storage devices, and storage capacity are measured in bytes, while data transfer rates are measured in bits. For instance, an SSD may have a storage capacity of 240 GB, while a download may transfer at 10 Mbps. Additionally, bits are also used to describe processor architecture, such as a 32-bit or 64-bit processor.
For example in Internet Protocol (IP) networking, IP addresses contain 32 bits or 4 bytes. The bits encode the network address so that it can be shared on the network. The bytes divide the bits into groups.
The IP address 192.168.0.1, for instance, is encoded with the following bits and bytes:
11000000 10101000 00000000 00000001.
Bits are grouped into bytes to, generally speaking, increase the efficiency of computer hardware,including network equipment, disks and memory.
REFRENCES
http://computer.howstuffworks.com/bytes1.htm
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