Rational Software

Rational Software was an independent software development company until 2003, when it was bought by IBM. It sought to advance its customers' practice of Modern Software Engineering through process, tools, and service.

Rational Machines was founded by Paul Levy and Mike Devlin in 1981 to provide tools to expand the use of modern software engineering practices, particularly explicit modular architecture and iterative development. Its initial product -- the Rational Environment -- was an integrated development environment for the Ada programming language, which provided good support for abstraction through strong typing. The Rational Environment was organized around a persistent intermediate representation (DIANA), providing users with syntactic and semantic completion, incremental compilation, and integrated configuration management and version control. The Rational Environment ran on custom hardware, the Rational R1000, which implemented a high-level architecture optimized for execution of Ada programs in general and the Rational Environment in particular. Rational later added code generators targeted to then-popular instruction set architectures such as the VAX, 68K, and X86; much of this was accomplished through a partnership with Tartan Labs, founded by Bill Wulf to commercialize his work (PQCC) on optimizing code generators semi-automatically produced from architecture descriptions. The company's name was changed from "Rational Machines" to "Rational" to avoid emphasizing its proprietary hardware.

Rational's field organization was noteworthy for its team-based approach to customer success. Sales teams were led by an account representative, and included 3 to 5 software engineers referred to as technical representatives - "TechReps". Sales teams engaged with their customers both pre-sales and post-sales, and were held accountable for customer success as well as for revenue targets. This approach encouraged deep engagement between TechReps s and customers, which in turn helped Rational develop a significant experience base in the successful development of complex long-lived software. The Best Practices that underlie the later Rational Unified Process (RUP) - iterative development, component-based architecture, modelling, quality by design, requirements management, and automated testing -- are all traceable to this experience base.

In 1990, Rational launched three parallel development efforts: re-implementation of the Rational Environment (for Ada) to run on Unix-based workstations from Sun and IBM, development of a comparable Rational Environment for C++ to run on Unix-based workstations from Sun and IBM, and development of a workstation-hosted modeling tool based on a graphical notation developed by Grady Booch. The modeling tool, Rose 1.0, was introduced at OOPSLA in 1992, but performed poorly in multiple dimensions and was withdrawn from the market. Apex, the Rational Environment for Ada for standard platforms, was launched on the Sun and IBM platforms in 1993, and the Rational Environment for C++ followed a year later. A version of Apex that ran on Microsoft Windows NT was successfully developed and released by Rational's Bangalore team.

In 1994, Rational acquired Verdix, a public company that produced a wide array of Ada compilers targeted to many architecture/OS combinations. The resulting entity was named "Rational Software", and promptly integrated the Rational Ada and C++ environments with the code generators and runtimes developed by Verdix.

The development of Rose 2.0 combined a Windows-based Booch notation editor called Object System Designer (acquired from Wisconsin-based Palladio) with a new intermediate representation, and with new semantic analysis, code generation, and reverse engineering capabilities. The latter, which allowed prospective customers to analyze existing C++ code to produce "as-built" navigable class diagrams, helped overcome Rational's late re-entry into the market for object-oriented modeling tools. Rose 2.0 ran on Windows PCs and on several Unix-based workstations.

In October James Rumbaugh joined the company and in the fall of Rational acquired Ivar Jacobson's firm Objectory AB This brought within one company all three leading software methodologists Grady Booch, James Rumbaugh and Ivar Jacobson. These "three Amigos" were immediately tasked with the unification of their work. To eliminate the method fragmentation that was impeding commercial adoption of modeling tools, their Unified Modeling Language (UML) was developed openly, providing a level playing field for all tool vendors. At its 1.0 release, the Unified Modeling Language was handed over to the Object Management Group, which has managed its subsequent development.

Philippe Kruchten, a Rational TechRep, was tasked with the assembly of an explicit process framework for modern software engineering. This effort applied the HTML-based process delivery mechanism employed by Objectory with Rational's 15-year experience base in working with customers developing significant software systems. The resulting "Rational Unified Process" (RUP) completed a strategic tripod: a process that guided development, tools that automated the application of that process, and services that accelerated adoption of both the process and the tools.

The momentum established by Rose and the UML enabled Rational to establish a partnership with Microsoft, which then saw model-based development as a means of attracting enterprise-scale developers to the Windows platform; Rational's aim was to secure Microsoft's public support for modelling in the software development process. This engagement with Microsoft stimulated Rational to consider the broader Windows-based IT market. With only one Windows-based tool (Rose) supporting RUP, Rational chose to acquire tool companies with Windows-based products that could be integrated to provide comprehensive RUP support. Beginning in 1996, Rational acquired Requisite, SQA, Performance Awareness, and Pure-Atria (Purify, ClearCase); these joined the previously-acquired Verdix, Objectory, and Palladio teams to create a set of business units whose mission was to create individually best-of-breed products that could be combined in interoperating Suites. The Rational Suite for Windows was introduced in 1999, and drove the company's transition to the Windows platform as its primary source of revenue.

In 2001, Rational founders Levy and Devlin founded Catapulse -- an independent company aimed at providing hosted software development services using products from Rational and elsewhere. Catapulse was later acquired by Rational.

Rational peaked at $850M in revenues and ~4000 employees. After the .com crash, its revenues declined to $650M, but it was dominant, profitable, and cash-rich (~$600M) when its founders chose in 2003 to sell the company to IBM for $2B. It is now a division of the IBM Software Group.