The system/38 differs from conventional machines in a number of ways. The most important differences are o A database management system is integrated with the operating system. All data files are data base files. o Main memory and auxiliary storage (disk) are treated as one unit. Inter alia, this means that not only programs but also data files are paged into and out of main me mory. o All objects must be addressed via a library and by name; also the libraries themselves (namely via QSYS). The user has no way of reaching physical addresses (which he can't find out anyway). o Large parts of the operating systems are in microcode. o There is no assembler language. The unique features of the S/38 make it necessary for the auditor to put in some effort to learn how the system works. Otherwise he is likely to misunderstand important aspects of the data processing performed on the system. Some knowledge is also required to use the system's fea tures effectively for obtaining an understanding of the system and performing compliance and substantive tests on it. 2. Hardware Characteristics 2.1. General Information The IBM S/38 is a general purpose data processing system designed to provide ease of use, reliability, and an inte grated database. The system has a unique architecture with an integrated relational data base design that supports interactive workstation applications as well as traditional batch applications."