The AS/400, now known as IBM iSeries, is a midrange computer system introduced by IBM in 1988. It is designed for small to medium-sized businesses and is known for its reliability, scalability, and integrated database capabilities. The system runs on the IBM i operating system, which supports various programming languages and applications. The AS/400 features a unique architecture that combines hardware and software, allowing for efficient processing and data management. It is widely used for business applications, including accounting, inventory management, and customer relationship management, making it a popular choice for enterprises looking for robust computing solutions.