In the late 1970s, Daniel Brickline was a student at the Harvard Business School. One day he was staring at columns of numbers on a blackboard when he got the idea for computerizing the spreadsheet. The result, VisiCalc, was the first of the electronic spreadsheet software or electronic worksheets. Most spreadsheet packages enable you to link spreadsheets together-this is called dynamic file linking. If a number, such as an expense amount, is changed in one spreadsheet, the change is automatically reflected in other spreadsheet files that might be affected by the change. Thus, the amount of data being manipulated can be enormous. Spreadsheets can also display data in graphic form, such as in pie charts or bar charts, which are easier to read than columns of number. Today the principle electronic spreadsheet software are Excel, Lotus 1-2-3 and Quattro Pro.
Traditionally, it was simply a grid of rows and columns, printed on special green paper that was used by accountants and others to produce financial projections and reports. A person making up a electronic spreadsheet software offer spent long days and weekends at the office penciling tiny numbers into countless tiny rectangles. When one figure changed, all the rest of the numbers on the spreadsheet had to be recomputed- and ultimately there might be wastebaskets of jettisoned worksheets.