# Bits Bytes etc

## Contents

# Units

### CraigNDave

https://www.youtube.com/watch?v=9kzCoDFrMGE&list=PLCiOXwirraUCa2MYf_oSM94uvwIGPMZ1q

### Computer Science Tutor

https://www.youtube.com/watch?v=Ol3PxSpEeT4&list=PL04uZ7242_M6O_6ITD6ncf7EonVHyBeCm

# New Units

**Computer Science units are now based around the powers of 10**

**Powers of 10**

For each unit add 3 to the power to go up in powers of 10 for each unit of data for example : 1GB = 10^9 with the power of 10 being 1,000,000,000 bytes However if you subtract three pwoers from 10^9 then 10^6 = 1,000,000 bytes

## The Bit

The Bit is a single binary digit used in computing and is represented using either a 1 or 0. The two values of a single digit act as an On or Off function or True/False and putting them together can result in unique functions as 1 digit can control one variable and another digit can control an entirely different variable. By putting multiple bits together functions become more complex and have more outcomes as if you set one value to true it can lead to another set of values different to what you would get if it was set to false. Putting 8 of theses bits together is called a byte

## The Byte

A byte is made up of **8 bits**, and larger amounts of data are based around the value of a byte (e.g Gigabyte being 1,000,000,000 bytes). A single byte represents one binary number, as it is made up of a total of 8 1's and 0's. A single byte can also represent a single character, such as the letter B.

## Kilo Byte

A Kilo Byte is 1000 bytes. It is also a multiple of the byte unit with the prefix (kB).

## Mega Byte

A Mega Byte is 1000 Kilo Bytes, thus is 1000000 Bytes. In Base 10 the prefix Mega is 10^6.

## Giga Byte

1 giga byte (1Gb) is 1000 megabytes and also 1 Gigabyte (G / GB) = 10^9 bytes = 1,000,000,000 bytes

## Tera Byte

1 TeraByte = 1,000 GigaByte, 10^12 bytes

## Peta Byte

**Symbol** PB
**Power** 10^15

## Exa Byte

**Symbol**: EB
**Power**: 10^18
**Bytes**: 1,000,000,000,000,000,000

## Zetta Byte

**Symbol**: ZB
**Power**: 10^21
**Bytes**: 1,000,000,000,000,000,000,000

## Yotta Byte

Yottabyte (YB) is a unit of digital information that equals to one septillion (10^24).

# Old Units

**Units based around powers of 2, according to the spec you don't need to know these**

## Powers of 2

A power of two is a number of the form 2^{n} where n is an integer. (e.g. 7).

Power of 2 | Equivalent |
---|---|

2^{0} = 1 |
(Anything to the power of itself is always 1) |

2^{1} = 2 |
2x1 = 2 |

2^{3} = 4 |
2x2 = 4 |

2^{4} = 8 |
2x2x2 = 8 |

2^{5} = 16 |
2x2x2x2 = 16 |

Etc.

## Kibi Byte

A kibibyte is a multiple of the unit byte, with the binary prefix 'kibi' meaning 2 to the power of 10 or 1024 bytes.
Therefore meaning 1 kibibyte is 1024 bytes.

The unit symbol for a kibibyte is KiB.

## Mebi Byte

The binary prefix mebi means 2^20; therefore one mebibyte is equal to 1048576bytes = 1024 kibibytes.

The unit symbol for the mebibyte is MiB.

1 MiB = 2^20 bytes = 1024 kibibytes = 1048576bytes

## Gibi Byte

1 GiB is equal to 2^30. (Two to the power of thirty)

1 GB = 0.931323 GiB

## Tebi Byte

A tebibyte is a unit of data storage that equals 2 to the 40th power, or 1,099,511,627,776 bytes. While a terabyte can be estimated as 10^12 or 1,000,000,000,000 bytes, a tebibyte is exactly 1,099,511,627,776 bytes.

## Pebi Byte

A **Pebi Byte** is a **multiple of the unit byte**, used for **digital information.**

The prefix for **pebi** is **Pi**
and the prefix for **pebibyte** is **PiB**
1,125,899,906,842,624 bytes and is equivalent to **1024 tebibytes** or **1 pebibyte. **

to get from **pebibytes to bits**, you can do:
pebibytes times 2 to the power of 50 **(PiB x 2^50)** or pebibytes times 1024 to the power of 5 **(PiB x 1024^5)**
and to get from **bits to pebibytes**, you can do:
bits divided by 2 to the power of 50 **(bits / 2^50)** or bits times 1024 to the power of 5 **(bits / 1024^5)**

## Exbi Byte

2^60

## Zebi Byte

2^70

## Yobi Byte

2^80