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A System Metaphor can
Simplify the Design

Lessons Learned

 When we rewrote the VCAPS system at Ford we wanted to choose a system metaphor but found that it was difficult. We had data from a variety of sources that had no commonality it seemed.
 A breakthrough was when we discovered that all the data could be uniformly represented as if it were a bill of material. So we chose bill of material as our system metaphor. In the old system it was often very difficult to find the right data. In the new system it was obvious where it would be.
 From top to bottom our new model has the same metaphor. After we had gotten down
the road with this new metaphor we measured that this uniformity was going to save us 95% in database size. Also, we now had one and only one way of accessing data no mater where it came from or what it represented.
 This uniformity also simplified our algorithms and reduced processing time. We went from processing times averaging about 15 minutes to coming back immediately.

Don Wells
eXPerience Software

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Copyright 1999 J. Donovan Wells all rights reserved.