TinySol: A 3KB Klondike Solitaire That Runs on Any DOS Machine

TinySol (formerly MonoSol) is a free Klondike Solitaire game designed for vintage computers, especially those with monochrome displays. Written in x86 assembly and assembled with NASM, it fits in just 3KB and runs on any PC with an 8086 or better. The developer's goal was a game that looks sharp in 640×400×2 mode on GRiD gas-plasma displays while being small enough to include in ROMs without consequence.

The game supports keyboard and mouse input, in-game state save/restore (undo), save/load to disk, auto-finish when possible, and Microsoft-style scoring sans timer. It changes video modes on the fly via F1-F4 keys, auto-detecting the display except for the AT&T 6300 mode, which is only auto-selected on certain GRiD computers.

Compatibility and Testing

TinySol has been tested on real hardware including an IBM 5150 (8088, 640KB, CGA, MS-DOS 3.30), a GRiDCase 1520 (286, CGA/ATT), and a Pentium 233 with VGA. It also runs under emulation, including DOSBox, and even on an emulated 8086 with just 64KB RAM and MS-DOS 2.0.

Notably, CuteMouse, a popular DOS mouse driver, doesn't support the AT&T 6300 video mode—the mouse works but the cursor is invisible. The developer tested with Microsoft Mouse driver v6 instead. DOSBox doesn't require a mouse driver since it's integrated.

Version History and Community

Version 1.0 launched in March 2022. v1.1 added an ending screen and optimizations. v1.2 introduced scoring, save-to-file, and auto-finish. v1.3, released in May 2026, offers multiple builds (full, med, tiny, micro) and was first distributed as hard copies at Vintage Computer Festival Southwest 2026.

The game has a small but enthusiastic following. One user, Joseph, emailed that he'd been looking for a DOS Klondike game that works with just the keyboard and draws 3 cards at a time. The developer also received help from Óscar Toledo G. (nanochess.org), who identified a sprite rendering issue on VirtualBox for Mac that was resolved by clearing the direction flag before calling Int 10h.

TinySol is a testament to what's possible with tight assembly code and a clear focus on compatibility. It's not just a game; it's a piece of software engineering that respects the constraints of the hardware it targets.