OVERVIEW COMPANY TD Technologies, Inc. Cleveland, Ohio BUSINESS EXPERTISE Systems engineering for design of complex electrical and mechanical systems APPLICATION System Level Automation Tool for Engineers (SLATE(tm)) PLATFORMS Sun, Hewlett-Packard BUSINESS CHALLENGE Translate customer needs into complete products VERSANT SOLUTION Created foundation of a dynamic, multi-user information system to manage the entire product life cycle EXISTING CUSTOMERS Texas Instruments, Westinghouse, Hughes, Battelle, Renault, NASA, TRW, Honeywell, Sandia National Labs

TD Technologies considered a number of different database technologies when the prototype for the SLATE environment was being developed. Object databases seemed to make the most sense, but at the time, early 1991, the ODBMS industry was just beginning to gain a significant foothold in the corporate world. They decided to use a relational database because the technology was more mature and, they thought, more commercially viable.

"It was a big mistake," Srinivasan recalls. "The performance was horrible for what we were trying to do, and we were writing a lot of code just to synchronize information between the database and the memory. It didn't take us long to read the writing on the wall: relational technology simply was not a good fit for what we were trying to do."

Three SLATE requirements, in particular, led TD Technologies to take a closer look at the potential of ODBMS technology:

• They wanted to give users the ability to save or abort design changes which have occurred during a SLATE session that might last anywhere from minutes to days.
• All users needed to be able to read all design elements at all times.
• Multi-user data access had to be fast enough to support complex, interactive design sessions.

In the meantime, the ODBMS market as a whole had matured significantly, so they felt more comfortable with the stability of the major ODBMS vendors. TD Technologies performed some performance tests to establish once and for all whether an object database could meet their requirements for SLATE.

"The closer we looked, the better object technology looked," reports Don Candy, vice president and general manager of the SLATE division. "One vendor, in particular, looked very promising: Versant Object Technology."

WHY VERSANT?

TD Technologies evaluated several ODBMS vendors to verify that an object database was indeed the best way to achieve their objectives, including Versant, Object Design, Inc. and Objectivity, Inc.

ODBMS vendors, like all database providers, employ some type of locking scheme to control shared access to the database and ensure that applications do not interfere with each other and corrupt database contents. Locks allow multiple users to access the same objects in the same database at the same time in a cooperative, controlled, and predictable manner.

"We chose Versant because it was the only database that offered object-level locking," Srinivasan says. "This is essential to the team development approach we offer with SLATE, since it allows multiple engineers to work simultaneously on a single design."

"Versant has the most complete and flexible scheme for locking database resources," Srinivasan says.

Versant also offers long transactions so developers can check out information from a project database and check it into a private database for an entire SLATE session. For example, a chip designer could use a long transaction for a series of design sessions investigating an approach to layout and routing. Long transactions in Versant can last for as long as an application requires, and may even involve several sessions interrupted by breaks.

"The locks for these long transactions are persistent," Srinivasan says, "which means they are recorded on disk so as to survive system failures. Versant offers a great deal of flexibility for granting and denying long-lock requests. These long transactions coupled with the personal database allow a designer to work uninterrupted and complete a given task. When ready, those updates are then gracefully integrated into the project whole."

But best of all was Versant's performance. "Versant ran between two and four times faster than the Ingres relational database we had been using in the first version of SLATE," Srinivasan reports. "After our evaluations, we wondered why we hadn't adopted an object database sooner. Having Versant in our SLATE environment has made the difference between a helpful systems engineering tool and a tool that is truly exceptional."

SLATE IN ACTION

Today, Versant has become the foundation of a dynamic, multi-user information system for managing the entire product life cycle, from initial definition through design, development, manufacturing, deployment, and maintenance.

Consider, for example, a design for a commuter car, Srinivasan suggests. Engineers see that car as a cohesive system that can be broken into various subsystems. Each of these subsystems contributes to the overall design, and elements within one system relate closely to elements in other systems.

SLATE makes it easy to control and organize these design activities, since its object database naturally encourages a structure in which a single, complex design can be decomposed into smaller and smaller elements, represented by parent and child objects. Objects can inherit attributes from other objects, and external rules can operate on the objects to calculate values that relate to all of them, such as to verify requirements for the car's overall weight, cost, or fuel requirements.

"The entire engine of the car could be a parent object, with various engine subsystems represented as children of that parent object, such as the drive train, the cooling system, and the exhaust system," Srinivasan explains. "All these objects are stored in the project database, and Versant allows concurrent, multi-user access by the systems engineers who are laying out the requirements and establishing the design."

SLATE enables systems engineers to evaluate design alternatives early in the manufacturing cycle, Candy adds, when changes are easy to make. This avoids costly mistakes later on. It also allows them to take quantifiable attributes, such as weight or cost, and distribute them to the various elements of the design. "If the car must be manufactured for $6,000 or less, this total cost can be allocated to the car's various subsystems: the engine must not cost more than $800, the transmission must not cost more than $300, and so forth," he says.

You can also annotate certain elements within the design, and generate design documents from these notes, Srinivasan adds. This is essential when government standards and regulations must be met, such as those pertaining to emissions control.

"These regulations translate into specific requirements for how the car's major systems are designed," Srinivasan says. "They generally originate from documents, which can be captured as objects, stored by Versant, and applied to the numerous system components. The emissions requirement becomes an object, the engine design becomes an object, the link between the design and the requirement becomes an object, and on and on. The object technology paradigm fits very well."

All of the SLATE information is stored in the object database, with Frame Technology Inc.'s FrameMaker used to organize documents. SLATE reads the FrameMaker files, then stores the information as objects in the Versant database, Srinivasan explains. SLATE then reads these documents from the database to create the requirements for the project at hand.

"Versant is the key to what we call a concurrent activity information system," Candy says. "A system that enables teams of people to work concurrently in a multi-user, real-time environment. It's an excellent way for engineers to relate complex regulations and requirements to the various elements of an evolving design, whether it is a design for a software program or a jet engine."

OBJECTS EVERYWHERE

The flexibility of the SLATE environment has made it especially popular with manufacturing companies involved in concurrent engineering and complex design work, Candy adds, as well as with environmental regulation companies. TD Technologies continues to attract larger and larger clients, and is currently targeting its efforts towards the Big Three US automobile manufacturers.

"Object technology is a requirement for information systems in the future, which means Versant has put us in a position of strength," Candy concludes. "They have an excellent product that is mature enough for intense, production-level work. Their engineers are top notch and they have been extremely supportive of our efforts. There is no doubt in my mind - with Versant, we believe we have picked the winner."