The software basically prompted the operator and patient on performing Pulmonary Function Exams. The HP85 connected to the Pulmonary Function Machine and collated data, generated reports, etc.
It was only a few hundred lines of code – probably the best (most profitable) lines of code I have ever written. I sold the software to a third party company that provided support to hospitals for the Pulmonary Function machine. I didn’t make a ton off of it, but dollar per lines of code I did fairly well. Especially since I also was hired by the company to do “from home” tier three tech support. For about 8 months I would get an occasional phone call and talk a user, or a representative of the company through some task, or troubleshooting.
Sometimes these calls resulted in some new code needing to be written – either to address a new feature request, fix a bug, or just modify the behavior of the application based on how it was used. I got paid for each of those lines of code. Paid a lot considering the time (early 80’s).
After 8 months the company I sold the software to was purchased (I think by HP, but I can’t recall for certain) and my deal with them ended. But as best I can tell those ~300 lines of code were worth close to $300 a line by the time the arrangement ended.
The latest application I am writing is well over 1300 lines of code (so far), it doesn’t do anywhere near as much as this previous application did (in terms of relevance), and I won’t make a dime off it.
Moral of the story? I dunno – “Simple Sells”?