WIKIBOOKS
DISPONIBILI
?????????

ART
- Great Painters
BUSINESS&LAW
- Accounting
- Fundamentals of Law
- Marketing
- Shorthand
CARS
- Concept Cars
GAMES&SPORT
- Videogames
- The World of Sports

COMPUTER TECHNOLOGY
- Blogs
- Free Software
- Google
- My Computer

- PHP Language and Applications
- Wikipedia
- Windows Vista

EDUCATION
- Education
LITERATURE
- Masterpieces of English Literature
LINGUISTICS
- American English

- English Dictionaries
- The English Language

MEDICINE
- Medical Emergencies
- The Theory of Memory
MUSIC&DANCE
- The Beatles
- Dances
- Microphones
- Musical Notation
- Music Instruments
SCIENCE
- Batteries
- Nanotechnology
LIFESTYLE
- Cosmetics
- Diets
- Vegetarianism and Veganism
TRADITIONS
- Christmas Traditions
NATURE
- Animals

- Fruits And Vegetables



ARTICLES IN THE BOOK

  1. Adobe Reader
  2. Adware
  3. Altavista
  4. AOL
  5. Apple Macintosh
  6. Application software
  7. Arrow key
  8. Artificial Intelligence
  9. ASCII
  10. Assembly language
  11. Automatic translation
  12. Avatar
  13. Babylon
  14. Bandwidth
  15. Bit
  16. BitTorrent
  17. Black hat
  18. Blog
  19. Bluetooth
  20. Bulletin board system
  21. Byte
  22. Cache memory
  23. Celeron
  24. Central processing unit
  25. Chat room
  26. Client
  27. Command line interface
  28. Compiler
  29. Computer
  30. Computer bus
  31. Computer card
  32. Computer display
  33. Computer file
  34. Computer games
  35. Computer graphics
  36. Computer hardware
  37. Computer keyboard
  38. Computer networking
  39. Computer printer
  40. Computer program
  41. Computer programmer
  42. Computer science
  43. Computer security
  44. Computer software
  45. Computer storage
  46. Computer system
  47. Computer terminal
  48. Computer virus
  49. Computing
  50. Conference call
  51. Context menu
  52. Creative commons
  53. Creative Commons License
  54. Creative Technology
  55. Cursor
  56. Data
  57. Database
  58. Data storage device
  59. Debuggers
  60. Demo
  61. Desktop computer
  62. Digital divide
  63. Discussion groups
  64. DNS server
  65. Domain name
  66. DOS
  67. Download
  68. Download manager
  69. DVD-ROM
  70. DVD-RW
  71. E-mail
  72. E-mail spam
  73. File Transfer Protocol
  74. Firewall
  75. Firmware
  76. Flash memory
  77. Floppy disk drive
  78. GNU
  79. GNU General Public License
  80. GNU Project
  81. Google
  82. Google AdWords
  83. Google bomb
  84. Graphics
  85. Graphics card
  86. Hacker
  87. Hacker culture
  88. Hard disk
  89. High-level programming language
  90. Home computer
  91. HTML
  92. Hyperlink
  93. IBM
  94. Image processing
  95. Image scanner
  96. Instant messaging
  97. Instruction
  98. Intel
  99. Intel Core 2
  100. Interface
  101. Internet
  102. Internet bot
  103. Internet Explorer
  104. Internet protocols
  105. Internet service provider
  106. Interoperability
  107. IP addresses
  108. IPod
  109. Joystick
  110. JPEG
  111. Keyword
  112. Laptop computer
  113. Linux
  114. Linux kernel
  115. Liquid crystal display
  116. List of file formats
  117. List of Google products
  118. Local area network
  119. Logitech
  120. Machine language
  121. Mac OS X
  122. Macromedia Flash
  123. Mainframe computer
  124. Malware
  125. Media center
  126. Media player
  127. Megabyte
  128. Microsoft
  129. Microsoft Windows
  130. Microsoft Word
  131. Mirror site
  132. Modem
  133. Motherboard
  134. Mouse
  135. Mouse pad
  136. Mozilla Firefox
  137. Mp3
  138. MPEG
  139. MPEG-4
  140. Multimedia
  141. Musical Instrument Digital Interface
  142. Netscape
  143. Network card
  144. News ticker
  145. Office suite
  146. Online auction
  147. Online chat
  148. Open Directory Project
  149. Open source
  150. Open source software
  151. Opera
  152. Operating system
  153. Optical character recognition
  154. Optical disc
  155. output
  156. PageRank
  157. Password
  158. Pay-per-click
  159. PC speaker
  160. Peer-to-peer
  161. Pentium
  162. Peripheral
  163. Personal computer
  164. Personal digital assistant
  165. Phishing
  166. Pirated software
  167. Podcasting
  168. Pointing device
  169. POP3
  170. Programming language
  171. QuickTime
  172. Random access memory
  173. Routers
  174. Safari
  175. Scalability
  176. Scrollbar
  177. Scrolling
  178. Scroll wheel
  179. Search engine
  180. Security cracking
  181. Server
  182. Simple Mail Transfer Protocol
  183. Skype
  184. Social software
  185. Software bug
  186. Software cracker
  187. Software library
  188. Software utility
  189. Solaris Operating Environment
  190. Sound Blaster
  191. Soundcard
  192. Spam
  193. Spamdexing
  194. Spam in blogs
  195. Speech recognition
  196. Spoofing attack
  197. Spreadsheet
  198. Spyware
  199. Streaming media
  200. Supercomputer
  201. Tablet computer
  202. Telecommunications
  203. Text messaging
  204. Trackball
  205. Trojan horse
  206. TV card
  207. Unicode
  208. Uniform Resource Identifier
  209. Unix
  210. URL redirection
  211. USB flash drive
  212. USB port
  213. User interface
  214. Vlog
  215. Voice over IP
  216. Warez
  217. Wearable computer
  218. Web application
  219. Web banner
  220. Web browser
  221. Web crawler
  222. Web directories
  223. Web indexing
  224. Webmail
  225. Web page
  226. Website
  227. Wiki
  228. Wikipedia
  229. WIMP
  230. Windows CE
  231. Windows key
  232. Windows Media Player
  233. Windows Vista
  234. Word processor
  235. World Wide Web
  236. Worm
  237. XML
  238. X Window System
  239. Yahoo
  240. Zombie computer
 



MY COMPUTER
This article is from:
http://en.wikipedia.org/wiki/Megabyte

All text is available under the terms of the GNU Free Documentation License: http://en.wikipedia.org/wiki/Wikipedia:Text_of_the_GNU_Free_Documentation_License 

Megabyte

From Wikipedia, the free encyclopedia

 
This article is about a unit of data measurement. For the cartoon character, see Megabyte.

A megabyte is a unit of information or computer storage equal to approximately one million bytes. It is commonly abbreviated MB. Mb is used for megabits.

Definition

Because of inconsistencies in the use of SI-derived prefixes such as kilo- and mega-, the exact number can be any one of the following:

  1. 1,048,576 bytes (1,0242, 220): This definition is used for nearly all discussions of computer memory (as computer addresses are naturally powers of two, making it efficient to manufacture memory in power-of-two capacities) and file storage. As of 2005, most software uses this definition to express storage capacity (e.g. file size).
  2. 1,000,000 bytes (1,0002, 106): This is the definition recommended by SI and IEC. It is used primarily in networking contexts and most storage media, particularly hard drives and DVDs. This definition of 'mega-' as a SI prefix is consistent with the other SI prefixes, and with many other uses of the prefix in computing, such as CPU clock speeds or measures of performance.
  3. 1,024,000 bytes (1,0241,000): This definition occurs rarely. It was used in a small number of storage contexts, most notably the "1.44 MB" (actually 1,474,560 bytes, of which only 1,457,664 bytes are usable on a Windows computer), and the "3.5-inch" (actually 90 mm) high-density floppy diskette.

Several attempts to resolve these inconsistencies have been proposed, most notably the standard created by the IEC to redefine 1,048,576 bytes as a "mebibyte". This standard has been adopted by several organizations, such as the NIST and IEEE. See Binary prefix for more information.

Megabytes in use

Usually, the storage capacities of hardware devices such as hard drives are given as 1 megabyte = 1,000,000 bytes (especially for items made in Japan, as Japan has standardized on the metric definition). Other capacities, such as for the RAM capacity of most personal computers, are given as 1 megabyte = 1,048,576 bytes (known unambiguously as a "mebibyte").

Depending on compression methods and file format, a megabyte of data can roughly hold:

  • One "typical" sized photograph with reasonably good quality
  • Roughly, a minute of near CD-quality MP3 compressed music (at 128 kbit/s)
  • Approximately 100 pages of single-spaced 12 point font text in Microsoft Word.
  • Approximately 3 seconds of DVD-quality video

A digital photograph produced by a typical digital camera in 2005 might be 14 MB depending on the camera's image resolution and level of compression used.

Until the introduction of hard drives with a capacity of one gigabyte or more, the capacity of hard drives was measured in megabytes.

Consumer confusion

Note that computer memory is addressed in base 2, due to its design, so memory size is always a power of two. It is thus convenient to measure in binary units. Other computer measurements, like storage hardware size, data transfer rates (despite the fact that hardware storage, and data transfer rates are both directly related to storing or moving chunks of data in base 2 computer memory), clock speeds, operations per second, and so on do not have an inherent base, and are usually measured in decimal units. Consumers who are (initially) unaware of varying meanings of the abbreviations often feel shortchanged when they discover the difference, and claim that manufacturers of drives and data transfer devices are using the decimal measurements in an intentionally misleading way to inflate their numbers, though these measurements are the norm in all fields other than computer memory and storage.

For instance, if a hard drive is said by a vendor to store 140 GB of data, the disk can store 140109 bytes. Generally, operating systems allocate and report disk and files sizes in binary units, and present them using abbreviations (e.g GB, MB, KB) also used by the decimal system, so this drive would be reported as "130 GB" (actually 130.38 GiB). (Furthermore, the drive wouldn't be able to store files with a total filesize of 130.38 GiB, either, due to filesystem overhead. See Partition (computing).)

Several legal disputes have been waged over the confusion. See Binary prefix - Legal disputes.

See also

  • binary prefix
  • kilobyte
  • gigabyte
  • mebibyte
  • megabit
  • orders of magnitude (data)

External links

  • Historical Notes About The Cost Of Hard Drive Storage Space
  • the megabyte (established definition in Networking and Storage industries; from whatis.com)
  • International Electrotechnical Commission definitions
Retrieved from "http://en.wikipedia.org/wiki/Megabyte"