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Megabyte is a SI
SI prefix

An SI prefix is a name or associated symbol that precedes a basic unit of measure to form a decimal multiple . The abbreviation SI is from the French language name Syst?me International d?Unit?s ....
-multiple (see prefix mega-) of the unit byte
Byte

A byte is a basic unit of measurement of Computer storage in computer science. In many computer architectures it is a Byte addressing memory address space....
 for digital information storage
Computer storage

Computer data storage, often called storage or memory, refers to computer components, devices, and recording medium that retain digital data used for computing for some interval of time....
 or transmission and is equal to 106 (1,000,000) bytes. However, due to historical usage in computer-related fields it is still often used to represent 220 (1024×1024 or 1,048,576) bytes. In rare cases, it is used to mean 1000×1024 (1,024,000) bytes. It is commonly abbreviated as Mbyte or MB (compare Mb, for the megabit
Megabit

A megabit is a unit of Computer data storage, abbreviated Mbit .1 megabit = 106 = 1,000,000 bits which is equal to 125,000 bytes....
).

term "megabyte" is ambiguous because it is commonly used to mean either 10002 bytes or 10242 bytes.






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Megabyte is a SI
SI prefix

An SI prefix is a name or associated symbol that precedes a basic unit of measure to form a decimal multiple . The abbreviation SI is from the French language name Syst?me International d?Unit?s ....
-multiple (see prefix mega-) of the unit byte
Byte

A byte is a basic unit of measurement of Computer storage in computer science. In many computer architectures it is a Byte addressing memory address space....
 for digital information storage
Computer storage

Computer data storage, often called storage or memory, refers to computer components, devices, and recording medium that retain digital data used for computing for some interval of time....
 or transmission and is equal to 106 (1,000,000) bytes. However, due to historical usage in computer-related fields it is still often used to represent 220 (1024×1024 or 1,048,576) bytes. In rare cases, it is used to mean 1000×1024 (1,024,000) bytes. It is commonly abbreviated as Mbyte or MB (compare Mb, for the megabit
Megabit

A megabit is a unit of Computer data storage, abbreviated Mbit .1 megabit = 106 = 1,000,000 bits which is equal to 125,000 bytes....
).

Definition

The term "megabyte" is ambiguous because it is commonly used to mean either 10002 bytes or 10242 bytes. The confusion originated as compromise technical jargon for the byte multiples
SI prefix

An SI prefix is a name or associated symbol that precedes a basic unit of measure to form a decimal multiple . The abbreviation SI is from the French language name Syst?me International d?Unit?s ....
 that needed to be expressed by the powers of 2 but lacked a convenient name. As 1024 (210) is roughly equal to 1000 (103), roughly corresponding SI multiples began to be used as approximate binary multiples. By the end of 2007, standards and government authorities including IEC
International Electrotechnical Commission

The International Electrotechnical Commission is a Non-profit organization, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies ? collectively known as "electrotechnology"....
, IEEE, EU, and NIST, had addressed this ambiguity by promulgating standards requiring the use of megabyte to describe strictly 10002 bytes and "mebibyte
Mebibyte

The Mebibyte is a standards-based binary prefix of the byte, a unit of Computer data storage. Mebibyte is abbreviated MiB.The unit prefix mebi was defined by the International Electrotechnical Commission in December 1998....
" to describe 10242 bytes. This is reflected in an increasing number of software projects, but most file managers still show file sizes in "megabytes" ("MB") in the binary sense (10242 bytes). The term remains ambiguous and it can follow any one of the following common definitions:
  1. 1,000,000 bytes (10002, 106): This is the definition recommended by the International System of Units (SI
    International System of Units

    The International System of Units is the modern form of the metric system and is generally a system devised around the convenience of the number ten....
    ) and the International Electrotechnical Commission IEC
    International Electrotechnical Commission

    The International Electrotechnical Commission is a Non-profit organization, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies ? collectively known as "electrotechnology"....
    . This definition is used in networking
    Computer network

    A computer network is a group of interconnected computers. Networks may be classified according to a wide variety of characteristics. This article provides a general overview of some types and categories and also presents the basic components of a network....
     contexts and most storage media, particularly hard drives, Flash
    Flash memory

    Flash memory is a non-volatile memory computer storage that can be electrically erased and reprogrammed. It is a technology that is primarily used in memory cards and USB flash drives for general storage and transfer of data between computers and other digital products....
    -based storage, and DVD
    DVD

    DVD, also known as "Digital Versatile Disc" or "Digital Video Disc,"is a popular optical disc data storage device media format. Its main uses are video and data storage....
    s, and is also consistent with the other uses of the SI prefix
    SI prefix

    An SI prefix is a name or associated symbol that precedes a basic unit of measure to form a decimal multiple . The abbreviation SI is from the French language name Syst?me International d?Unit?s ....
     in computing, such as CPU clock speeds or measures of performance
    FLOPS

    In computing, FLOPS is an acronym meaning FLoating point Operations Per Second. The FLOPS is a measure of a computer's computer performance, especially in fields of scientific calculations that make heavy use of floating point calculations, similar to instructions per second....
    .
  2. 1,048,576 bytes (10242, 220): This definition is most commonly used in reference to computer memory
    Computer memory

    Computer memory is usually meant to refer to the semiconductor technology that is used to store information in Electronics devices. Current primary computer memory makes use of integrated circuits consisting of silicon-based transistors....
    , but most software that display file size or drive capacity, including file managers also use this definition. See Consumer confusion
    Gigabyte

    Gigabyte is an SI prefix-multiple of the unit byte for Computer data storage. Since the giga- prefix means 109, gigabyte means 1,000,000,000 bytes ....
     (in the "gigabyte" article).
  3. 1,024,000 bytes (1000×1024): This is used to describe the formatted capacity of USB flash drive
    USB flash drive

    A USB flash drive consists of a Flash memory#NAND memories-type flash memory data storage device integrated with a USB interface. USB flash drives are typically removable and rewritable, much smaller than a floppy disk , and most USB flash drives weigh less than an ounce ....
    s and the "1.44 MB" 3.5 inch HD floppy disk
    Floppy disk

    A floppy disk is a data storage medium that is composed of a disk of thin, flexible magnetic storage medium encased in a square or rectangle plastic shell....
    , which actually has a capacity of 1,474,560 bytes.


Megabyte examples

Floppy Disk 90mm
Depending on compression methods and file format
File format

A file format is a particular way to encode information for storage in a computer file.Since a disk drive, or indeed any computer storage, can store only bits, the computer must have some way of converting information to 0s and 1s and vice-versa....
, a megabyte of data can roughly be:
  • a 1024×1024 pixel bitmap
    Bitmap

    In computer graphics, a bitmap or pixmap is a type of computer storage organization or used to store digital images. The term bitmap comes from the computer programming terminology, meaning just a map of bits, a spatially mapped bit array....
     image with 256 colors (8 bpp color depth
    Color depth

    Color depth or bit depth, is a computer graphics term describing the number of bits used to represent the color of a single pixel in a Raster graphicsped image or video frame buffer....
    ).
  • 1 minute of 128 kbit/s MP3
    MP3

    MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a digital audio Encoder format using a form of lossy data compression. It is a common audio format for consumer audio storage, as well as a de facto standard encoding for the transfer and playback of music on digital audio players....
     compressed music.
  • 6 seconds of uncompressed CD audio.
  • a typical book volume in text format (500 pages × 2000 characters per page).


See also

  • binary prefix
    Binary prefix

    In computing, a binary prefix is a set of letters that precede a unit of measure to indicate multiplication by a power of two. In certain contexts in computing, such as computer memory sizes, units of information storage and communication traffic have traditionally been reported in multiples of powers of two....
  • kilobyte
    Kilobyte

    Kilobyte is a unit of Computer data storage equal to either 1,024 bytes or 1,000 bytes , depending on context.It is abbreviated in a number of ways: KB, kB, K and Kbyte....
  • gigabyte
    Gigabyte

    Gigabyte is an SI prefix-multiple of the unit byte for Computer data storage. Since the giga- prefix means 109, gigabyte means 1,000,000,000 bytes ....
  • mebibyte
    Mebibyte

    The Mebibyte is a standards-based binary prefix of the byte, a unit of Computer data storage. Mebibyte is abbreviated MiB.The unit prefix mebi was defined by the International Electrotechnical Commission in December 1998....
  • megabit
    Megabit

    A megabit is a unit of Computer data storage, abbreviated Mbit .1 megabit = 106 = 1,000,000 bits which is equal to 125,000 bytes....
  • orders of magnitude (data)
    Orders of magnitude (data)

    This is a list of multiples for Computer data storage, measured in bits. This article assumes a descriptive attitude towards terminology, reflecting actual usage by the speakers of the language....


External links

  • (established definition in Networking and Storage industries; from )