After my sophomore year in high school, I had a summer job doing some IT work for a very small company that organized medical research. I was very familiar with

After my sophomore year in high school, I had a summer job doing some IT work for a very small company that organized medical research. I was very familiar with Excel, which was a huge strength, but also my weakness. I hadn't truly programmed before, but was an expert at throwing together absurdly long, chained together formulas in Excel that could sanitize some data - After a few weeks of work, I ended up making a really poor Excel VBA code that had a time complexity of O(n!). It would take a few hours to churn through the dataset. I went back this year to visit some of my old coworkers - some of whom I'm still good friends with - and saw they were using the same macro from years ago. I sat down, wrote a small Python CSV script in about 5 minutes that did what I was trying to do back then which ran in about a minute or so. I was incredibly surprised that they were still using that from so long ago, but they explained that they just hadn't had anyone bother to fix it because they didn't know it could be done better. I'm sure your DOS program was the same, and that they didn't know any better. I wouldn't be surprised if that system was in use for another 10 years or so.