What is a megabyte (MB)? – Definition and Example
Megabytes (MBs) represent collections of digital information, commonly referring to two different numbers of bytes, each containing eight bits. In the context of computer memory, one definition of a megabyte is 1,048,576 bytes (220 bytes). while in most networking and computer storage applications, it denotes 1,000,000 bytes (106 bytes). Either definition equates roughly to the file size of a 500-page e-book.
What is a Bit?
The term “bit” derives from “binary digit” and signifies “yes or no” answers to unambiguous questions, stored in computers as either zeroes or ones. For instance, whether a door is locked can be answered with one bit. This binary system underpins all digital information storage in telecommunications and computing.
What are Bytes?
Currently, a byte typically comprises eight bits, although this number has varied historically. Eight bits conveniently store a single character, including format data such as capitalization. While information is seldom stored in bits alone, the byte serves as the standard unit of information addressed in computer architectures.
The Source of Confusion with Megabytes
Confusion regarding megabytes arises from the method of byte multiplication. Computers use binary number systems rather than decimal (base-10) systems, favoring grouping bytes based on powers of two, hence the 220 definition of a megabyte. There’s a recent movement advocating for prefix definitions consistent with the metric system, which would endorse the 106 definition for a megabyte.
Common Uses of Megabytes
Megabytes are prevalent file sizes in personal computing and business transactions. Text documents often occupy less than one megabyte, while high-resolution images from digital cameras typically consume several megabytes. Video files of movie length can exceed 1,000 megabytes, and compact disc read-only memories (CD-ROMs) typically hold around 700 megabytes, while digital video discs (DVDs) often boast capacities of several thousand megabytes.
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