It was the first killer app, the spark for Apple's early success and a trigger for the broader PC boom that vaulted Microsoft to its central position in business computing. And within a few years, it was tech-industry roadkill. From a report: The story of VisiCalc, a humble spreadsheet program that set the tech world ablaze 40 years ago, has reverberated through the industry and still influences the decisions of executives, engineers and investors. Its lessons include the power of simplicity and the difficulty of building a hypergrowth company in a hypergrowth industry. Indeed, its lessons have been so internalized by today's tech titans that they have significantly inoculated themselves against that sort of tumultuous, competitive dynamism -- aka disruption. VisiCalc was unveiled on June 4, 1979, and shipped that October. Dan Bricklin first dreamed it up in a classroom at Harvard Business School -- the room now bears a plaque commemorating his idea -- and partnered with Bob Frankston, who coded VisiCalc and collaborated in its design. When users opened VisiCalc, they would see a character-based grid where numbers or text could be manipulated. It was handy for budgeting, financial projections, bookkeeping and making lists. Today it's instantly recognizable as a spreadsheet, as familiar to us as a blinking cursor, but at the time it was a novel idea that had to be experienced to be understood. Initially VisiCalc ran only on the Apple II, a then-revolutionary new personal computer and Apple's first major consumer product. While some Apple II models had just 4 kilobytes of RAM, VisiCalc demanded a whopping 32KB. (Even the cheapest of today's iPhones have tens of thousands of times as much RAM.) Further reading: VisiCalc Turns 25, Creators Interviewed (June, 2004).Read more of this story at Slashdot. Click here to read full news..