Daniel Singer "Dan" Bricklin (born 16 July 1951, Philadelphia, PA), is referred to as “The Father of the Spreadsheet”, is the American co-creator, with Bob Frankston of the VisiCalc spreadsheet program. He earned undergraduate technical degrees from MIT in 1973. In 1977 he went to Harvard for an MBA. In 1979, he created VisiCalc, making it the first electronic spreadsheet commercially available for home and office use. It ran on an Apple II computer. VisiCalc is widely credited for fueling the rapid growth of the personal computer industry (the first killer app). Instead of doing financial modelling with manually calculated spreadsheets, and having to recalculate many cells in the sheet by hand, VisiCalc allowed the user to change any cell, and have the entire sheet automatically recalculated. This could turn 20 hours of work into 15 minutes.

Bricklin was inspired by noticing his professor constantly entering data manually on a chalkboard, then laboriously making erasures and recalculating the rows and columns by hand. Visicalc sold more than 700,000 units in its first six years and 1+ million throughout its product life. Lotus Development purchased VisiCalc in 1985 and terminated the product in favor of its own, more popular Lotus 1-2-3.

Bricklin continues to serve as president of two small software companies.

Ozzie created Lotus Notes (later IBM Notes)

Allen is a Microsoft Co-Founder

Ritchie and Thompson created the C programming language

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