Imagine seamlessly accessing data from IBM AS/400, HP 9000 and PC servers, regardless of the type of client platform. Better still, imagine developing an application that runs on multiple clients and integrates with these servers without prior knowledge of what those platforms are.
Creating such a truly distributed computing environment is the goal of a growing class of software called “middleware,” which provides a common interface for diverse front ends and servers. With so many approaches to client/server computing and a diverse installed base, the demand for middleware is increasing. By definition, client/server applications demand the seamless integration of software across computer platforms, operating systems and networks.
One new middleware product slated to ship next month is Oracle Corp.’s Oracle Glue for Windows, which provides access from Microsoft Corp.’s Visual Basic and Excel, Dynamic Data Exchange-enabled applications and programs that support dynamic link libraries to Oracle and IBM DB2 servers, Borland International Inc.’s dBASE and Paradox files, and Sharp Electronics Corp.’s Wizard 7000 and 8000 series electronic organizers.
“There’s an overwhelming need for middleware,” said Tucker McDonagh, managing director of Tucker Network Technologies Inc. in South Norwalk, Conn. Standards emerging in the market, such as the Vendor-Independent Messaging API (application programming interface), will “relieve some of the complexity [of disparate environments], but middleware will always be a requirement,” he said.
Middleware provides an API for exchanging messages between pieces of distributed applications, McDonagh said. Some programs also can work with multiple protocol stacks, so separate applications can interoperate across unique LANs and WANs.
McDonagh divides middleware into five groups: messaging products with an API and communications services for distributed applications; remote procedure calls, with an API that works over multiple protocol stacks; database/data-access packages, which link to various databases; on-line transaction-processing programs, which add error-control, security and recovery aspects; and traditional middleware, or file-transfer software.
Developers of client/server software are providing links to multiple clients and back ends. Trifox Inc.’s Vortex, for example, includes software that allows users to access a variety of database servers, such as Ingres, Sybase, Informix, Oracle and Ultrix/SQL.
Oracle Corp. also offers a software suite that eases accessing multiple clients and back ends. With Oracle Card, a front-end development tool, both PCs and Apple Computer Inc. PowerBooks can access an Oracle database, according to Frank Naeymi-Rad, MIS director for the University of Health Science at the Chicago Medical School.
“Oracle Card provides us with one platform for running both PCs and Macintosh computers,” he said. The application allows medical students and doctors at Cook County Hospital to use PowerBook notebook computers to enter data while at a patient’s bedside and transfer it over a network that is also accessed by DOS PCs.
In other cases, middleware serves as the catalyst for creating a distributed network. The state of Alabama, for example, is developing a system that uses Information Builders Inc.’s (IBI’s) EDA/SQL to link OS/2-based clients at 43 prospective counties with an IBM DB2 mainframe server.
“We run multiuser EDA/SQL at the gateway to ship requests to the host for updates to the DB2 server,” said David Murrell, information-systems manager for the state’s advanced technology group in Montgomery. “We really use EDA/SQL to accomplish a distributed-database environment.”
EDA/SQL stands out among database tools because it can be used with more than 100 front-end tools to access more than 50 types of databases on 35 different platforms.
While most middleware currently supports specific protocol stacks and applications, industry giants intend to establish all-encompassing standards. Digital Equipment Corp. (DEC), for example, engineered Network Application Support (NAS), an architecture and products designed to provide the ultimate level of open systems.
DEC has more than 90 NAS products for nine hardware platforms. Examples include its Compound Document Architecture for documents with graphics and text and Application Control Architecture Services, which provide object-oriented tools for communicating between applications.
Third-party developers have also embraced the NAS architecture. More than 3,000 NAS applications are available from such firms as Computer Associates International Inc., IBI and Microsoft.
Digital Communications Associates Inc. (DCA) also plans to unveil its own platform this spring. The firm recently announced a universal communications architecture to provide consistent access, features and APIs. DCA’s first product based on this architecture will be QuickApp, an application-development tool that shields programmers from communications-transport protocols, including LU 2, LU 6.2 and LU 0.
Users of tools such as Visual Basic and Mozart Systems Corp.’s Application Renovation development software will be able to create end-user applications without knowledge of communications software, according to DCA officials in Alpharetta, Ga.