E=mc2 is a milestone in the progress of science. And for those who think ground breaking inventions end there, think again. There is one more without which you have to re-start your computer, give the password, log in and log off....Phew! This is what we would be doing without the three-point mantra of "ctrl alt del".

No apple fell on him that day. He did not shout "Eureka Eureka". It was an instant brainwave. All he took was five long minutes to sit in front of his computers like hundreds of engineers do and that's it, he relieved PC users from loads of stress.

One of David Bradley's tasks as an IBM PC engineer was to engineer the keyboard and he got tired of the resetting the computer for the self-test procedure. And he wanted an easy way to reboot the computer. The result is the famous trio.

It is a lot more complicated than it looks like. But Bradley is a PhD in electrical engineering from Purdue University. He joined IBM in June 1975 as an engineer in Boca Raton, Florida. He was one of the "dirty dozen" who are credited with the creation of IBM PC.

Even though "ctrl alt del" is most noted of his achievements, he is credited for a lot more than that. He holds seven US patents and is also accredited for developing the all-famous ROM BIOS. He is an adjunct professor at Florida Atlantic and North Carolina State Universities. His academic career is equally bright. He is also the author of 'Assembly Language Programming for the IBM Personal Computer'.

And at the 20-year celebration of IBM PC, when Bradley said, "I might have invented it (ctrl alt del) but Bill made it famous"; everyone laughed but Bill Gates did not even try to. He kept a grim face as he knows that this man gains every time the "undisputed king of Computers" Mr Gates' Windows don't work!