Book excerpt: Annotation A hands-on approach to learning library-object structure, utilities and database management capabilities, application development tools, and OS/400 Control Language (CL), for the AS/400 computer. Twelve lessons, based largely on lab exercises, teach students how to communicate with the system, and use its many features, including CL, Query/400, logical files, DFU, SQL, and SDA. Annotation copyrighted by Book News, Inc., Portland, OR.