books

M a n a g e r ' s SAA o v e r v i e w

Systems Applicatmn

Architecture by L R Libutti

TAB Books (1990), $24.95, 204pp

This book gives a basic overview of IBM's Systems Application Architecture (SAA), their strategic approach to tie heteroge- neous IBM systems together. It provides both technical and business-related infor- mation about SAA, and is intended for managers with a basic technical background who wish to acquire knowl- edge about IBM's SAA strat- egy, solutions and products.

The material is not techni- cal enough to serve as a guideline for those who want to do detailed design or implementation work based on SAA concepts or products. The book does not require any profound knowledge of computer hardware or com- munication architectures, but familiarity with major IBM systems is helpful.

Written in an easy to read style, the book has numerous figures to illustrate the con- cepts (although some figures carry little technical informa- tion and are rather redun- dant). It is well structured, starting with a historical SAA background and an overview of its components, then focusing on more detailed aspects and future evolution.

Clearly the author has profound experience with IBM products from his 30 years with the company. However, technical concepts are often intermingled with business-related considera- tions, making it difficult to acquire the essential techni- cal information itself. Perhaps it would have been appropri- ate to separate technical and business considerations.

A clear motivation of the requirements which have lead to the SAA effort is first given. It then establishes a

uniform operating systems model as the base of SAA (being realized for the MVS and VM operating systems on the System/370, OS/400 on the mid-range system AS/400, and OS/2 on the personal workstation PS/2). Based on this model, the author introduces and explains the SAA compo- nents (common user access, defining uniform user inter- action rules; common com- munication support, enabling heterogeneous communica- tion based on IBM-SNA/OSI; and the common application programming interface, defining uniform language and service interfaces). However, details are only given for the CPI -- for tech- nical details on the CUA and CCS further sources will be required.

The major influences of SAA on enabling applications are then outlined. These are roughly divided into technical issues and business support, the former being concerned with cooperative and dis- tributed processing and appli- cation development. While the problems become clear, description of the technical achievements to solve these problems is quite general, and does not provide much detail. In particular, no dis- tinction between cooperative and distributed processing is made. The scope of dis- tributed processing seems limited, focusing on remote data access, print and display and execution. More advanced problems of heavily distributed programs with direct interprocess communi- cation, data and service repli- cation and fault-tolerance or real-time requirements are not addressed.

On a more positive note, the description of SAA appli- cation development support outlines promising directions. The author focuses on impor- tant CASE requirements like covering the whole software lifecycle, a uniform design data representation and seamless tool support.

A brief overview of the roles of some major IBM locations in the process of SAA development is then given, and proves useful to obtain a first impression of SAA activities and contribu- tors. It would have been appropriate to collect other business-related observations spread throughout the book in this chapter as well. The cooperation of SAA-based systems and Unix/AIX is also covered. Both systems, says the author, can interoperate in a relatively seamless way, but only a few technical details confirming this postu- lation are actually given.

The rest of the book out- lines the future direction of SAA, such as the seamless integration of the different operating systems and full coverage of the software development cycle by tools.

The most positive aspects of the work are its clear structure, its easy readability and its focus on actual SAA products. One criticism is its inappropriate mix of techni- cal and business material. It can, however, be recom- mended for managers who wish to gain an insight into IBM's SAA approach, but it is not a technical guide for system designers. Consider- ing that this is one of the few sources of information on SAA, it is worth its price if a basic SAA overview is what is required by the reader.

Dr Alexander Schill University of Kaflsruhe,

Germany

vol 14 no 9 november 1991 ,573