Bits.+Bytes.

What are bits, bytes, and other units of measure for digital information?
A bit is a binary digit, the smallest increment of data on a computer. A bit can hold only one of two values: 0 or 1, corresponding to the electrical values of off or on, respectively.

Because bits are so small, you rarely work with information one bit at a time. Bits are usually assembled into a group of eight to form a byte. A byte contains enough information to store a single ASCII character, like "h". A kilobyte (KB) is 1,024 bytes, not one thousand bytes as might be expected, because computers use binary (base two) math, instead of a decimal (base ten) system.

Computer storage and memory is often measured in megabytes (MB) and gigabytes (GB). A medium-sized novel contains about 1 MB of information. 1 MB is 1,024 kilobytes, or 1,048,576 (1024x1024) bytes, not one million bytes. Similarly, one 1 GB is 1,024 MB, or 1,073,741,824 (1024x1024x1024) bytes. A terabyte (TB) is 1,024 GB; 1 TB is about the same amount of information as all of the books in a large library, or roughly 1,610 CDs worth of data. A petabyte (PB) is 1,024 TB. Indiana University is now building storage systems capable of holding petabytes of data. An exabyte (EB) is 1,024 PB. A zettabyte (ZB) is 1,024 EB. Finally, a yottabyte (YB) is 1,024 ZB.

Many hard drive manufacturers use a decimal number system to define amounts of storage space. As a result, 1 MB is defined as one million bytes, 1 GB is defined as one billion bytes, and so on. Since your computer uses a binary system as mentioned above, you may notice a discrepancy between your hard drive's published capacity and the capacity acknowledged by your computer. For example, a hard drive that is said to contain 10 GB of storage space using a decimal system is actually capable of storing 10,000,000,000 bytes. However, in a binary system, 10 GB is 10,737,418,240 bytes. As a result, instead of acknowledging 10 GB, your computer will acknowledge 9.31 GB. This is not a malfunction but a matter of different definitions.

101 = 10 102 = 10*10 = 100 103 = 10*10*10 = 1,000 106 = 1,000,000
 * We count in base 10 by powers of 10:**

21 = 2 22 = 2*2 = 4 23 = 2*2*2 = 8 210 = 1,024 220 = 1,048,576
 * Computers count by base 2:**


 * So in computer jargon, the following units are used:**
 * ~ Unit ||~ Equivalent ||
 * 1 kilobyte (KB) || 1,024 bytes ||
 * 1 megabyte (MB) || 1,048,576 bytes ||
 * 1 gigabyte (GB) || 1,073,741,824 bytes ||
 * 1 terabyte (TB) || 1,099,511,627,776 bytes ||
 * 1 petabyte (PB) || 1,125,899,906,842,624 bytes ||
 * Note:** The names and abbreviations for numbers of bytes are easily confused with the notations for bits. The abbreviations for numbers of bits use a lower-case "b" instead of an upper-case "B". Since one byte is made up of eight bits, this difference can be significant. For example, if a broadband Internet connection is advertised with a download speed of 3.0 M**b**ps, its speed is 3.0 mega**bits** per second, or 0.375 mega**bytes** per second (which would be abbreviated as 0.375 M**B**ps). Bits and bit rates (bits over time, as in bits per second [bps]) are most commonly used to describe connection speeds, so pay particular attention when comparing Internet connection providers and services.

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"What Are Bits, Bytes, and Other Units of Measure for Digital Information? - Knowledge Base." //University Information Technology Services//. University of Indiana. Web. 27 Sept. 2011.  ======