A killer app(lication) is a computer program that meets a need and causes the machine it is written for to take off in the marketplace.

For example, iTunes was the killer app for the iPod.

This month is the 30th anniversary of what many consider the killer app for personal computers -- the electronic spreadsheet -- a program that moved the PC from a hobbyist pursuit into the mainstream.

You might have guessed the PC's killer app would have been the word processor, but the spreadsheet better fit the limits of display and memory of PCs in 1979. And the spreadsheet allowed businesses to do what they could not do easily -- "what if" projections.

With the spreadsheet, businesses could set up a financial formula and then alter any number and instantly see how that would affect the outcome.

The first commercial spreadsheet, VisiCalc, went on sale in October 1979. It ran on the Apple II, Atari, Commodore PET and TRS-80.

VisiCalc is credited with turning the perception of the Apple II computer from a toy into a machine that could be used in business.

And because it foreshadowed the tremendous potential for personal computers in business, it was one of the motivations for IBM to bring out the IBM PC in 1981.

Philadelphia native Dan Bricklin got the idea for VisiCalc while sitting in a class at Harvard Business School and watching the amount of erasing and rewriting a professor had to do on the blackboard when he wanted to change one parameter in a long formula.

He got his friend Bob Frankston to help with the coding and the two formed a company to make the program.

Soon more powerful clones appeared, including SuperCalc, Microsoft's MultiPlan, Lotus 1-2-3 and AppleWorks' spreadsheet module.

Then came Excel, released for the MacIntosh two years before it was released for Windows 2.0. It remains the dominant spreadsheet program.

The electronic spreadsheet is so powerful, that tech curmudgeon John C. Dvorak, in a column for PCMag.com, said it created a "what-if society" that led to economic meltdown.

Be that as it may, take a power lunch and toast the spreadsheet.

Reader Joe e-mailed to tell me of an omission in my Oct. 4 column on Ivan Sutherland, a CMU alumnus often called the father of computer graphics.

Joe said that Mr. Sutherland had been at the CMU Robotics Institute in the 1980s and had built a six-legged walking robot that could be ridden. The robot was featured on the cover of Scientific American magazine.

Indeed that is so, and as Joe also points out, there is a seat plaque dedicated to Ivan Sutherland in the new Rashid Auditorium of the also new Gates Center for Computer Science at CMU.

By the way, Rick Rashid, for whom the auditorium is named, is no slouch himself.

He is senior vice president of research for Microsoft Corp.

He also was a lead developer of the Mach kernel, an integral part of several operating systems, most notably Apple's OSX.

Favorite Web sites are still coming in. A reader suggested kiva.com, truly a worthy site. It allows you to make small loans to entrepreneurs around the world as a way to help alleviate poverty.

Microlending can be a powerful weapon for good.

Keep those Web sites coming. Send suggestions to techman@post-gazette.com.

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