Intro to IT - Bits and Bytes 1

Bits and Bytes

BITModern computers are binary:

Everything is represented as being on one of two possible states: the state of being a 1the state of being a 0

A bit is the name for this smallest unit of storage in a computer.Bit is sort-of derived from "Binary digIT".

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DigitalMarketing and advertising folks have decided to

characterize anything that is based on bits as being "digital".Digital Cable TVDigital TelephoneDigital CameraDigital Audio

A better name might actually be discrete...

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ByteA ordered sequence of 8 bits.

Modern computers are based on memory systems organized as bytes of memory.

Memory sizes are typically given in numbers of bytes:"I would like a burger, fries and 512 Mega bytes of

memory"."I have a 32Giga byte iPhone, so I am better than

you".

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64 bit machineA machine that processes information in 64 bit

chunks.

The processor simply transports the information 64 bits at a time

The data-path, or bus, that runs to and from the processor is 64 bits wide.

8 bits still = byte, 8 bytes at a time

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How many bytes are there?

Keep in mind that a byte is a sequence of 8 bits.Each bit can be either a 0 or a 1.

How many sequences of 8 0/1s are possible?

Here are a few:

00000000 00010000 10000000 10101010

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# of byte values: derivation

2 x 2 x 2 x 2 x 2 x 2 x 2 x 2

# of bytes = 28 = 256

There are 256 possible byte values.

Although I may have 4 billion+ bytes in my iPod, there are only 256 different values, so many of them are identical!

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1 0 0 1 1 1 0 1

Base 2 Numbers(binary numbers)

We can talk about byte values by treating a byte as a base 2 number:

64 + 16 + 4 + 2 = 86

010101102 = 8610

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0 1 0 1 0 1 1 0128 64 32 16 8 4 2 1

HexadecimalBase 16 is also used when talking about byte values.

Each group of 4 bits corresponds to a single hex digit.

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Binary Hex Decimal

Binary Hex Decimal

0000 0 0 1000 8 8

0001 1 1 1001 9 9

0010 2 2 1010 A 10

0011 3 3 1011 B 11

0100 4 4 1100 C 12

0101 5 5 1101 D 13

0110 6 6 1110 E 14

0111 7 7 1111 F 15

Binary to Hex

110101102 = D616 = 21410

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1 1 0 1 0 1 1 0128 64 32 16 8 4 2 1

D 616 1

Binary-Hex-Decimal QuizFill in the blanks

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Base 10 Binary Hexadecimal