The most common fast, large, and expensive type of computer used in large businesses (including hospitals and other large healthcare facilities) for processing, storing, and retrieving data It is a large multiuser central computer that meets the computing needs large and medium sized public and private organizations. always have very high processing speeds (calculated in millions of processes per second, or, or MIPS, or in floating point operations per second, or FLOPS) are used for processing the large amount of repetitive calculations involved in handling billing, payroll, inventory control, and business operations computing.