A computer does all its computing with on/off switches, therefore it works in the binary number system, which has just two unique digits, 0 and 1. The off position is represented by 0; the 1 represents on. All computer memory and storage systems are also calculated in binary. There are three commonly used measurements, a kilobyte, a megabyte, and a gigabyte.

Kilobyte (K or Kb) – in decimal systems, kilo stands for 1,000 but in binary systems a kilo is 1,024 (2 to the 10th power). It is, however, often used to loosely represent 1,000. The original IBM PC came which 64 K, which means that the main memory could store or process 65,536 bytes, or characters of information at any one time.

Megabyte (M or Mb or Meg) – a megabyte is 2 to the 20th power or 1,048,576 bytes. If your current computer has 256 Mb of memory, that means that the main memory can store or process approximately 268,435,456 bytes or characters of information at any one time. Quite an improvement over the original IBM PC!

Gigabyte (G or Gb) – a gigabyte is 2 to the 30th power or 1,073,741,824 bytes. A gigabyte is equal to 1,024 megabytes.