This nontechnical description of IBM AS/400 architecture and applications aims at the reader who wants an overall understanding of IBM’s application systems and how to use them in the business environment of departmental computing. The AS/400 is interesting for only two reasons: 150,000 of these systems are now installed, and they represent the largest implementation of an object-oriented architecture. The AS/400 is the successor to the IBM System/38, which was the sole survivor, or rather a phoenix rising from the ashes, of IBM’s PL architecture program, which was intended to replace the System/360. Like the System /38, the AS/400 excels in online transaction-oriented processing (OLTP) applications.

Because the AS/400 is a scalable product line within a large performance range, it can be configured in both large and small business environments for OLTP applications in such a way as to be cost competitive with either central mainframe or distributed workstation environments. The system is well supported by telecommunications hardware and software. It finds broad use as networked departmental systems in multinational corporations, that is, as a universal departmental computer with shared maintenance, software, applications, site licenses, and so on.

This book is well written, but I recommend it only for the reader with a casual interest in the subject. It could also be a good place for a novice to start learning about the AS/400 before consulting the IBM technical manuals (which are not so well written).