PO WEEHNAP PLICATIOM DEVELOPMENT. — NPPLJED INTELLIGENCE vo oe ao vo a JJ EN NA ARA a —— JULY 10, 1989 SNA: Fulfilling the Need for an Integrated Environment This is Part 1 of a series of articles on IBM's Systems Application Ar- chitecture (SAA). Integrat- ed computing environmentS such as SAA wi have a ma- jor impact on the software technologies of the 905. Systems Appli- cation Architecture, according to IBM Chairman John Akers, is the technology that will have the largest effect on IBM customers over the next five to 10 years. In many ways, the transition to SAA represents the most, significant change in IBM software environments since the introduction of the System/360 in 1964. As the name implies, SAA is an archi- tecture for building enterprisewide sys- tems of applications. But what, exactly is a software architecture? According to the dictionary, an archi- tecture is "a style and method of design and construction." As it applies to soft- ware, the word has also come to mean a specification of the fundamental ele- ments of structure. Thus, we can view SAA as the specification of both the fundamental elements of the enterprise- wide application structure and the style and method by which those elements are combined to build applications. SAA isnt a product.or family.of prod: ucts for building enterprisewide applica- tions. Its a consistent, open set of speci- fications for how these applications will be built. Many vendors, including IBM, have recognized the need for integrated com- puting environments. Today, organiza- Uons often mix many types of comput- ers. All the machines serve different, but sometimes overlapping, functions. They are programmed differently, have differ- ent user interfaces, and there's little communication between them. It's not easy to build applications that make the prm ge of differing machine capabil- environments is to provide ZELENEM a £onnections between all the machines, | so information and processes can be dis- tributed (reely among them. Additional objectives include the provision of con. sistent user interfaces for a tions. Such an environment promidco JN] ji , n a / Gal ing appli of the 19904. 1990s an "enterprise inf EIS is typically composed of many dif. porate mainframes, midrange 9 programmable workst a em orkstation IBM calis the computing meči tem, or EIS. As shown in the graph, an [erent types of machines, including cor- and programmable workstations. The machines are seamlessly connected with applications working cooperatively across machine boundaries. Each of the machines is assigned the functions that it does best. A primary strength of the program- mable workstation is its ability to act as the user's window into the EIJS. It pro- vides a consistent, and easy-to-use inter- face for all applications. The applica- tions that, are accessed might be execut- ing locally on the programmable workstation, remotely on any other ma: chine in the EIS, or cooperatively among multiple machines. The corporate and midrange host support the user interface, database and program-to-program communication functions. Furthermore, the functional components of the application that are best suited for different machines must be isolated. For example, an application that gath- ers data and updates a corporate data: base would divide its functions between the host and the programmable work- station. Support for the user interface, as well as the editing and validating of user input, would be performed on the programmable workstation in a highly interactive input session. Once the data is gathered and edited, the data would be sent transparently to the host for ad- A JN What SAA Aims o m to Provide port EUL ETA] I Pi pli, ea, 1 k, E L dei < ze.a ii LčiH za ni, nad dina pi pe ji; i 5 h sy šu ; zani M iii, za ee: si k, li S AE ae gi DE PEU, ' A durable architecture vie. pen! j j teka! nei ti j vd) 4 Mei: nuj a PE uni: ' 4h Fa Nivea ; Li ijiš de PTUJ kA, dl; bdi ip SRE gam sd, k Nosi a ee Ma BENIe H Ni, , | ME bei ME 4 j ped: Ji a La? ga Ef it $ TRST » Flexibility for evolutiondry growth ' Ability to link disparate IBM systems ln a company ' Ability to handle varigd workloads | VA consistent system across d company |" Ability to leverage čxistirig Investments Source: IBM Systems Journal —5—565—ŽIŠŽIŽŽŠJJŽ o SAA isnt a product for applications. It's a co Computers are best at coordinating mul- lluser access to databases and transac- tlon-processing applications. This host/ | zads to what are called lice. er applications. The host provides cen- pra Pe: Mu eli ent ap- a ns on n Di pi Dgrammabilc — Workstations (or other machines Tb work effectivelv in - kai nsistent, open set o pecs for hot these applications Vl be LLAL o —TDD DE RŽ S, feel. While primarily intended for the programmable workstation, CUA con: tains a subset that. can be used or nom programmable terminals. This allows ap- plications to take full advantage of menu-driven, windowing, graphical, pro- grammable-workstation interface capa- bilities, and still maintain existing appli: catjons for non-programmable terminals. CCSris the specification for inter: program communication. It is based | heavily on IBM's System Network Archi- tecture (SNA) but also includes support for X.25 protocols and Open Systems In- terconnect. (OSI) protocols. Most of CC5, such as LAN support, is shielded from the developer and user. Only the top-lev- el program-to-program services are di- rectly accessible. GPI specifies the developer's tools, in- cluding programming languages and ser- vices. The products that implement the CPI will be used for building EIS appli- cations. Different products will exist on different platforms, but to be SA A-com- pliant the programmer s interface to the products must be consistent and must follow the CPI specifications. IBM has specified SAA for four main operating system environments: MVS and VM on the System/370, 0S/400 on the AS/400, and OS/2 on the program- mable workstation. The OSI and X.25 communication protocols allow connec- tion to other non-supported envi- ronments. What: About. Unix? While IBM would prefer that everyone use 0S/2 on PS/2s, the company is aware that many users prefer Unix on workstations. For this reason, the devel- opment directions of IBM's version of Unix, AIX, parallel those of SAA. The programming and communication interfaces will gradually become the same between SAA and AIX. This will allow Unix systems to be seamlessly in- corporated as part of the enterprise in- formation system. Organizations that prefer Unix will be able to make Unix, ate than OS/2, the window on the John Avakian The tools are not all in place yet for building enterprisewide ditional processing sc unalogice The host portion of the anplicatinr Next week, I'll describe how the archi- ič ; pplication tectur ene) z would provide the database access an tures and standards embodied in eki also include more global zala a ZALA simplify the application-develop- on of the data, such as ensuring that ment process, S database Ing entries in the The Ja »the ma and Common Programmi log isfer Institute, 741 10th St. TI 1 the same look and Ne an information terly, is avail United aka building EIS applications, but the archi- tecture is well-understood. Organizations that wish to use SAA as early as possi- ble should start designing and building new applications with the clear separa- tion of functions reguired for SAA. As tools that implement SAA become avail- able, the affected modules can be con. verted from current technologies to SAA nes Martin Productivity Series rog High rov Mass. (800) 242-1240. For infor. (0524) 734 505. PRA z samote re m. E "mni EH E am! Sji RES PR" im om . ša vami o