At my first job, our entire order-entry and inventory management system was written in QBASIC. I wish I had the source to try it out with this.
I know someone who might, if we could figure out how to get it off a DOS 5.25" floppy!
The good news is that 5.25" floppies have tended to be more resilient to time than the 3.5" discs. Turns out just having less data spread over a larger space helped them in this regard.
Hardest part is usually trying to find working drives and a means of getting the data off the system.
That’s awesome. If you ever end up getting a copy of it, I’d love to stress-test QBasic-Core against it since I built in a virtual hard drive to allow File I/O (PUT for random access, PRINT to file number, etc.)
I’ve got a fairly large collection of several hundred programs from the early to late ’90s that I’ve been carefully testing A/B testing against period accurate hardware and my simulator but actual professionally used QBASIC-based applications from back with the source intact are hard to come by.