Dan Bricklin came up with the idea for an “electronic spreadsheet” while still a graduate student at Harvard Business School. He and Bob Frankston founded Software Arts, Inc. in 1979 to explore the idea and VisiCalc was the result.

First demonstrated at the National Computer Conference in June 1979, the Apple II version of VisiCalc was shipped on October 17, 1979. Although developed by Software Arts, VisiCalc was sold by Personal Software (later VisiCorp), a company founded in 1976 by Dan Fylstra and Peter Jennings.

VisiCalc for the Apple II was so successful that versions for other computers were inevitable. The initial targets were the Commodore PET, the Atari 800, and the TRS-80 Model I. The Commodore PET and the Atari 800 shared the same 6502 processor as the Apple II and could use the same VisiCalc code. But the TRS-80 version required converting the VisiCalc code to use the Z80 processor, a project undertaken by Seth Steinberg. Despite this, both the Atari 800 and TRS-80 versions were released in late 1980, almost a year after the release of the Apple II version.]]> http://www.trs-80.org/visicalc/feed/ 0