The production department uses a system that tracks work in progress to determine expected output so that production output and sales forecasts align. Its primary method of tracking work in progress is when a part hits a certain stage of production, it passes between a photo eye and the associated light source. This action causes an increment in the database.

Something is wrong, however. The plant manager told you, “We just had that expensive COBOL programmer in here to look at the system. The parts count is higher at later stages of production than in some earlier stages and that is physically impossible. The programmer says he can’t work with bad data, so you need to find any photo eye problems or network problems and fix them all.”

Assuming you do this and the problem persists, where do you look?

COBOL is very old. Though still in use, it is considered a legacy programming language. If the company still uses COBOL, that’s a good sign that legacy IT issues are causing these discrepancies. The COBOL part may be fine, but some legacy component may not be properly handling the inputs from the photo eyes via the plant’s network. The network itself could contain legacy components with both hardware and software issues.

Testing the photo eyes confirms that the input to the network is good. Next, monitor input and output from the network simultaneously to see if there is a difference. If there’s a mismatch, you have a network problem for the appropriate party to resolve. If there is not a mismatch, something in the IT system is corrupting the data. The solution probably involves a serious IT upgrade.