Turbo Pascal 5.5
Borland's Antique Software: Turbo Pascal v5.5-- circa 1989. What a great year. My junior year of high school. Using a Compaq 386/20MHz PC. Coding in QuickBASIC, dBASE III+, Clipper Summer '87, C, Assembler and Turbo Pascal.
I think TP introduced me to OOP which may be why I'm still partial to Delphi (the visual successor to Turbo Pascal legacy). Remember the Borland Graphics Interface (BGI)? The TurboCalc demo? Win.pas was a unit for creating frames in DOS using line-drawing characters-- had nothing to do with MS Windows of course.
Don't mind me... I'm just wallowing in nostalgia. Do you have any memories to share?