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One pairwise test case generator is Pairwise Independent Combinatorial Testing (PICT). This product is based on a tool that Microsoft themselves use. There is a recent new tool called QICT which accomplishes the same task. The beauty of QICT is that the source code is provided free of charge.
Pairwise testing is good for many test scenarios. Some good examples are testing databases and configuration data. I know that I often have an onslaught of test cases that I think need to be executed to provide full coverage. I might just have to use a tool such as PICT to make my job easier. This can potentially reduce the test time necessary, and improve my test throughput.