Defining Megabyte

• The Microsoft Press Computer Dictionary defines megabyte as either 1,048,576 bytes or 1,000,000 bytes. These varying totals came about because byte multiples needed to be expressed by computer-friendly base powers of 2, but lacked a convenient name (the prefix Mega- denotes factors of a million). Humans typically use the base 10 when assigning exponentiation (i.e. 10^6) to byte multiples. On the other hand, computers use a binary system where 2 is the base (i.e. 2^20) when dealing with byte multiples.
  
  

Breaking Down the Byte

• A byte is defined as eight computer bits. Bits are binary digits, the most basic units of computer information. A bit can only be one of two different values: either a 0 or a 1. They represent two states of information, such as off/on or yes/no.
  
  

Units of Information

• The smallest unit of computer information is the bit. Eight bits constitute one byte. 1,024 bytes equal one kilobyte. 1,024 kilobytes equal one megabyte. 1,024 megabytes equal one gigabyte. 1,024 gigabytes equal one terabyte. Today, most computer hard drive sizes are quantified in gigabytes. In the near future, hard drives will be quantified in terabytes.
  
  

Storage Space Quantities

• Computer manufacturers use the decimal system to define storage space quantities. Because computers use binary systems, a discrepancy between published hard drive capacity and computer-acknowledged hard drive capacity may arise. A computer that is advertised to contain 10 gigabytes of storage space (using a decimal system) is actually capable of storying 10,000,000,000 bytes. However, in the binary system used by computers, 10 gigabytes equals 10,737,418,240 bytes. As a result, instead of acknowledging the advertised 10 gigabytes, your computer will only read 9.31 gigabytes of storage space. This is the result of a difference in definition and should not be understood as a computer calculation error.