Turbo Pascal Compiler (2013)
The first ever computer program I wrote for $$$ was a retail point of sale system for a local pharmacy.  I used Turbo Pascal for it, complete with my own proprietary database files etc.!<p>Later on, I wrote a front end menu system (which simply gave a customisable easy to select option of applications to run in DOS) that ended up being used on thousands of PC's throughout businesses and almost every government department in my town.<p>Good Days.  I downloaded the original Turbo Pascal v 1.x a couple of years back, and intended to try re-writing that point of sale system again to see how much I still remembered > 30 years later.  Never got around to it, but I will make a concerted effort this year to try it out.  I may just try it on this web emulator, seeing as I am now on a Mac!<p>Thank you Anders Heljsberg!  And to these guys for building a web emulator of the original compiler.