Note: The information shown below uses measures only associated with data. For example, a kilo-anything is 1000 . . . except that when it is a kilobyte, it is 1024, an even power of two.
提示：以下信息中量度标准均与数据有关。如：kilo-表示1000………但在kilobyte中，它代表1024，一个2的偶次幂。

How Much Data Is That?

Whenever we discuss quantities of data, we tend to do it in the abstract. We speak of a kilobyte, or a megabyte or a gigabyte without really knowing what it represents.
我们总在抽象概念中讨论数据的大小。我们经常提到KB、MB、和GB，但并不知道它们到底代表什么。

The following table shows various quantities of bytes, in each power of ten. Usually, they are shown with multiples of 2 and 5 also. For example, 1 Kilobyte, 2 Kilobytes, 5 Kilobytes.
下表显示了字节所组成的各种数据单位，分别约用10的幂次方表示。他们也经常用2和5的倍数表示。比如：1KB（一千字节）、2KB（两千字节）、3KB(三千字节）。

All the examples are approximate and are rounded. For example, a computer card has 80 columns. If 50 columns contain data on a card, then two cards will be 100 bytes. Also, a 3-1/2 inch diskette can contain 1.4 Megabytes. Showing it as 1 Megabyte reflects both (a) the diskette not typically being filled and (b) rounding. Finally, a CD-ROM can hold more than 500 Megabytes. However, it is listed at that level as "typical" and as the closest match.
所有的例项都取约数或整数，如：一张存储卡有80列。如果其中50列包含数据，那么两张卡就包含了100个字节。同样，在3.5寸磁盘中可以储存1.4兆字节的信息，所以存储1兆字节数据并不代表一张磁盘的空间已被填满。另外一张只读存储器光碟至少可以存储500兆字节的数据。

Bytes (8 bits) 字节（8比特）

    * 0.1 bytes: A single yes/no decision (actually 0.125 bytes, but rounded here)
      0.1字节：一个是/否的指令（实际上是0.125字节，这里取整）
    * 1 byte: One character
      1字节：一个字符
    * 2 bytes:
    * 5 bytes
    * 10 bytes: One word (a word of language, not a computer word)
      10字节：一个词（语言中的一个词，不是指计算机信息单元）
    * 20 bytes:
    * 50 bytes:
    * 100 bytes: Telegram; two punched computer (Hollerith) cards
      100字节：电报；两张凿孔编码卡片的内容
    * 200 bytes:
    * 500 bytes:

Kilobyte（KB） 千字节，1024字节，2的十次方，约为1000或10的三次方
     1,024 bytes; 210;
     approx. 1,000 or 103

    * 1 Kilobyte: Joke; (very) short story
      1千字节：一个笑话或一个短篇故事的内容
    * 2 Kilobytes: Typewritten page
      2千字节：打字机打出来的一页的内容
    * 10 Kilobytes: Page out of an encyclopedia
      10千字节：百科全书中一页的内容
    * 20 Kilobytes:
    * 50 Kilobytes: Image of a document page, compressed
      50千字节：相当于一张压缩的文件图像
    * 100 Kilobytes: Photograph, low-resolution
      100千字节：相当于一张低分辨率的相片
    * 200 Kilobytes: Two boxes (4000) punched computer (Hollerith) cards
      200千字节：两盒（4000张）凿孔编码卡片的内容
    * 500 Kilobytes: Five boxes, one case (10,000 of punched computer (Hollerith) cards
      500千字节：五盒或一箱（10000张）凿孔编码卡片的内容

Megabyte （MB）兆字节，1024千字节（KB），2的20次方，约为10的六次方
     1,048,576 bytes; 220;
     approx 1,000,000 or 106

    * 1 Megabyte: Small novel; 3-1/2 inch diskette
      1兆字节：一部短篇小说或一张3.5英寸软磁盘的内容
    * 2 Megabytes: Photograph, high resolution
      2兆字节：一张高分辨率的相片所占的空间
    * 5 Megabytes: Complete works of Shakespeare; 30 seconds of broadcast-quality video
      5兆字节：相当于莎士比亚的所有著作；或30秒与广播质量相当的视频
    * 10 Megabytes: Minute of high-fidelity sound; digital chest X-ray; Box of 3-1/2 inch diskettes
      10兆字节：相当于一分钟的高保真音频信息；一张数码胸腔X光片；或一盒3.5英寸软磁盘所储存的内容
    * 20 Megabytes: Two boxes of 3-1/2 inch diskettes
      20兆字节：两盒3.5英寸软磁盘的内容
    * 50 Megabytes: Digital mammogram
      50兆字节：一张数码乳房X光片的内容
    * 100 Megabytes: Yard of books on a shelf; two encyclopedia volumes
      100兆字节：一书架书包含的内容；或两卷百科全书的内容
    * 200 Megabytes: Reel of 9-track tape; IBM 3480 cartridge tape
      200兆字节：一盘有9首歌的磁带；或一盘IBM3480盒式磁带的内容
    * 500 Megabytes: CD-ROM
      500兆字节：一张只读存储光盘的内容

Gigabyte （GB）
     1,073,741,824 bytes; 230;
     approx 1,000,000,000 or 109

    * 1 Gigabyte: Paper in the bed of a pickup; symphony in high-fidelity sound; broadcast quality movie
      1GB：相当于一章交响曲的乐谱；或与发行电影质量相当的视频的内容
    * 2 Gigabytes: 20 yards of books on a shelf
    * 5 Gigabytes: 8mm Exabyte tale
    * 10 Gigabytes:
    * 20 Gigabytes: Audio collection of the works of Beethoven; five Exabyte tapes; VHS tape used to store digital data
      20GB：所有贝多芬作品的音频集合；5盒安柏特磁带的内容；一盘储存数据的VHS（Video Home System，VHS式录放像机系统）录像带
    * 50 Gigabytes: Library floor of books on shelves
      50GB：图书馆中一层楼藏书的内容
    * 100 Gigabytes: Library floor of academic journals on shelves; large ID-1 digital tape
      100GB：
    * 200 Gigabytes: 50 Exabyte tapes
      200GB：50盒安伯特磁带的内容

Terabyte （TB）
     1,099,511,627,776 or 240;
     approx. 1,000,000,000,000 or 1012

    * 1 Terabyte: Automated tape robot; all the X-ray films in a large technological hospital; 50,000 trees made into paper and printed; daily rate of EOS (Earth Orbiting System) data (1998)
      1TB：一个自动化卡带装置所需的空间大小；一所大型技术医院的所有X光片；用五万株树做成的纸张的打印品；环地轨道系统的日运行量（1998年）
    * 2 Terabytes: Academic research library
      2TB：一个学术图书馆的藏书内容
    * 10 Terabytes: Printed collection of the U. S. Library of Congress
      10TB：美国国会图书馆所有藏书
    * 50 Terabytes: Contents of a large mass storage system
      50TB：一个大容量储存系统的内容

Petabyte （PB）
     1,125,899,906,842,624 bytes or 250
     approx. 1,000,000,000,000,000 or 1015

    * 1 Petabyte: 3 years of EOS data (2001)
      1PB：3年的EOS数据总和（2001年）
    * 2 Petabytes: All U. S. academic research libraries
      2PB：美国所有学术图书馆所藏内容的总和
    * 20 Petabytes: 1995 production of hard-disk drives
      20PB：1995年生产的所有硬盘的空间大小
    * 200 Petabytes: All printed material; 1995 production of digital magnetic tape
      200PB：世界上所有的打印材料；95年产所有的数码磁带包含的内容总和

Exabyte
     1,152,921,504,606,846,976 bytes or 260
     approx. 1,000,000,000,000,000,000 or 1018

    * 2 Exabytes: Total volume of information generated worldwide annually.
      2EB：每年全球产生的所有信息量总和
    * 5 Exabytes: All words ever spoken by human beings.
      5EB：人类所有语言的所有词汇量

Zettabyte
     1,180,591,620,717,411,303,424 bytes or 270
     approx. 1,000,000,000,000,000,000,000 or 1021
（据说如同全世界海滩的沙子总和）

Yottabyte
     1,208,925,819,614,629,174,706,176 bytes or 280
     approx. 1,000,000,000,000,000,000,000,000 or 1024
（据说相当于7000位人类体内的微细胞总和）