Wrote a program to manage the sale and rental of video tapes for an small business. I wrote it in 1984, using Turbo Pascal. The last time I checked the store was still running the same software in 2005.

The application was table driven, all important configuration items were stored in a text file as a key-value pair. It had a bar-code scanner and was tied into a cash drawer. Receipts were printed on small dot matrix printer.

It took about 4 weeks to write.

The best programming environment ever.