Unlike modern gigabyte-sized piano VSTs, the Z-Doc soundfont is highly optimized and efficient, running well on older hardware or for live performances where low latency is critical.
While many stock general MIDI (GM) pianos sounded thin and synthetic, independent developers began sampling real acoustic instruments. A developer known in internet communities as "Z-Doc" created and distributed this custom piano SoundFont. It quickly circulated through classic file-sharing hubs, forums like Doomworld and Hydrogenaudio, and early sampling repositories. Technical Design and Efficiency z-doc piano soundfont