Full form of $$S is OS/2 Spreadsheet

The term OS/2 Spreadsheet refers to spreadsheet software designed for the OS/2 operating system. OS/2, developed by IBM and Microsoft, was a robust operating system intended for both personal and professional computing. In this context, the OS/2 Spreadsheet played a significant role in business environments where data organization, calculation, and analysis were essential. These spreadsheets offered users a powerful tool for handling complex data sets with features like formulas, charts, and data management capabilities, supporting various financial and analytical tasks. Though OS/2 eventually gave way to other operating systems, the legacy of its spreadsheet applications remains a notable part of computing history, highlighting the evolution of digital productivity tools.

The symbol $$S is the reserved file extension (. $$S) for legacy OS/2 Spreadsheet files.