ma on PRENE NINO VEN Pace 70 This is the fourth in a se- ries of articles on rapid appli- cation develop- ment (RAD), a than traditional methods. Improved ap- plications-devel- opment life cy- cles are urgently needed to devel- op strategic applications more guickly, as well as to deal with the growing IM | PG WEEKNAPPLICATION DEVELOPMENT. — — APPLIED INTELLIGENCE [ type was successively refined. CASE | |. tools provided graphically oriented ways of expressing models and designs. Code generators, which could generate COBOL or other languages from high-level con: structs, were also created. ] Recently, these tools have been com: bined into powerful, integrated facilities. CASE tools for planning, data modeling, analysis and design were integrated with code generators. Prototyping capa- bility was linked into the design tools. And non-procedural languages, including SOL and report generators, were inte- grated into the CASE environment. | 'The most important feature of I-CASE is the ability to generate code directly tory typically stores enterprise models, data models and process models that are to be standard desigri components ; across tle organization. ' ' 'The developers, who can be miles . from the mainframe, connected to it by telephone lines, download a subset of the central repository design informa- tion into their local project-level reposi- tory, where it is accessible via the LAN file server to all members of'the design team. Individual members of the team can then transfer this information to their desktop machine and work with it local- ly. A desktop design analyzer checks the integrity of what is built. JANUARY 15, 1990 Use of Automated Tools Crucial to RAD Life-Cyele Success do uncoupled tools. The integrated tool set is the basis for RAD. In advanced I-CASE tools, all of the functions associated with planning, anal- ysis, design, consolidation of specification, analysis of specifications, code genera- tion, database generation, documentation generation and project management can be performed within a LAN using a net- work of desktop computers. No longer is there any need to inter- act with a remote mainframe computer, except to access shared, corporate-level design specifications. Formerly, code generators for ICASE tools were located on a mainframe; now they are rapidly moving to PCs. Today's PCs are powerful enough for complete development, code generation backlog of applications waiting to be de- veloped. Information systems need to be , retogled with technigues that can devel- op applications in months rather than years, days rather than weeks. The RAD life cycle addresses these concerns through a combination of high- ly focused management technigues and advanced applications-development technology. Unlike more conventional development life cycles, RAD empha- sizes the use of small, highly motivated teams of users and information-systems (IS) professionals, as well as extensive use of interactive, joint application-de- sign technigues. Applications develop- ment is performed in an iterative man- ner using integrated computer-aided sofiware engineering (CASE) tools capa- ble of generating code for complete ap- plications, The success of the RAD life cycle de- pends greatly on the use of automated tools. Organizations that have achieved high productivity with RAD typically use tool sets, such as integrated CASE ((-CASE) tools, to rapidly build applica- tions within an automated life cycle. These integrated tools, developed in the late 1980s, permit entire applica- o to be specified on the desktop. y integrated CASE products provide i i nalyze: a complete software-development envi- DENI mne ronment that supports the entire life-cy: j The key to building complex systems ne ie, Hi t Jo Avakan.— is to have small, autonomous teams AE Šeil s nei ža me so working simultaneously with powerful l- lake D de elp CASE tools, their work coordinated with zj GI reče faster, cheaper a model that is in the common I-CASE a ž k repository. ene Ge should pe o build People who have learned to manase Pom odkes ne (PO ELE may the RAD life cycles with I-CASE tools a report generator or a spread zaj ima look back on the earlier methodologies li i ] ij and compiling of programs that eventu- Distributed Development Environrnent a o Pe UČ 1 host computer. Using CASE tools with desktop code generators is generally faster than accessing a mainframe for code genera- tion and corhpiling. A developer should be able to design a system (or subsystem), generate code for it, test it, modify it and regenerate it as guickly as possible. In addition, he or she should be able to do this on a desk- top machine, completely debugging the logic on that machine and generatiny the linkages to the mainframe databases, the network and the operat- ing system. | Once fully tested on the PC, the code is handed over for execution and testing on the host machine on which it will eventually run. Complexity Calls for ICASE 'The more complex the project, the greater the need for I-CASE tools. As the complexity of a project increases, the gain in productivity, relative to the traditional COBOL life cycle, also in- creases. Complex projects have many | components that need to be integrated; thus, the integrating capability of the re- CASE Toči $ate š Porsonal Hakosltorj eslgn Aridl$žai Corporate Roposllory » Enterprise Modelg » Data Models — | « Process Models | Project-Level Repository Simple tools should be used to build simple systems. Most systems developed wilh RAD technigues, however, are likeljy to be complex and will reguire sophisticated tools. is sufficient.) Most, systems developed ly to be complex and will reguire phisticated tools. je š - In the early 19805, fourth-generation reguired result, rather than simply the with RAD technigues, however, are like- were invented. Nonprocedural languages made it possible to express the iterative development in which a proto- from the CASE design tool, 'The figure shows a typical distributed ECASE erivironment. Members ofa' | project design team usually work within a LAN. Each member has on his or her desk an CASE tool set with its owh re- pository and design analyzer. With the desktop tools, they can do planning, analysis, design and code generation. di Consolidation and : user. kole Auery languages and report« . cations across the pojo prelet nes ža opo emi lai odanse using a projectlevel repository that tp sna became important, leally resides on a file server within the auickly and see ho poka reacted oza me ai ad w to In oddltion, da may be | hem. typlng languages gave rise to ospinij E Periodically, the changes made to the subset are sent back to the project-evel repository, where they are consolidated with specifications from other members Jof the design tedm, under project-man- agement control/ A design analyzer then goes to work on the consolidated specifi- cations, detecting any discrepancies among the different analysts' work., A critical characteristic of an ICASE tool (as opposed to a CASE tool) is its ability to generdtč executable programs. A code generator is driven by the design '. workbench. The tight integration of the analysis and design tools with the code generator | results in much higher productivity than with horror. Guality systems simply cannot be built guiekly with the tradi- tional methods. 'The components of integrated CASE tools used with the RAD life-cyele pro- cess will be discussed in more detail in next week's column.a . : The concepts embodied in RAD are de- - seribed in a new volume in the James Martin Report Series. For more infor- mation on this volume, call (800) 242: 1240. For information on seminars, contact (in the United States and Can- ada) Technology 741 10th St, Santa Monica, Calif. 90402 (213) 394-8305. In Europe, con: tact Savant, 2 New St, Carnforth, la LA5 9BX United Kingdom (0524) 734 505.