Computer differences

Purpose differences. A computer can be built to count numbers or to measure physical relationships. A digital computer is one that directly counts the numbers (or digits) that represent numerals, letters, or other special symbols. In contrast to a digital machine, an analog computer is the one that measures physical values such as temperature or pressure. For example, a service station gasoline pump contains an analog processor that converts fuel flow measurements into quantity and price values. Desirable features of analog and digital machines are sometimes combined to create a hybrid computing system. In a hospital intensive-care unit, for example, analog devices measure a patient’s heart function, temperature, and other vital signs. These measurements are then converted into numbers and supplied to a digital component that monitors the patient’s vital signs and signals a nurse station if abnormal readings are detected.

Analog and hybrid processors are special-purpose machines, and they perform important tasks. But most computers in use today are digital devices. Digital computers can also be designed to perform one specific function. In a special function digital computer, the instructions are wired into or permanently stored in the machine. The processors installed in automobiles to control fuel, ignition, instrument and breaking systems are examples of such computers. Unlike their special-purpose cousins, general-purpose digital computers can store different programs and can thus be used in countless applications. By using different instructions, such a machine can process a payroll one minute and draw a chart the next.

Size differences

Modern computer systems vary in physical size from those that fill rooms to those with CPUs that can rest on the nail of your little finger. Generally, the larger the system, the greater are its processing speed, storage capacity, cost and ability to handle large numbers of powerful input and output devices. While the smallest processors are typically used by one person at a time, larger systems can simultaneously serve the needs of many users. For example, a large computer at an insurance company can process hundreds of customer policies at the same time that it’s accepting medical claims from scores of online workstations located in hospitals and doctors’ offices.

Date: 2015-04-20; view: 973