However the notion of operating the inside of a computer with outside tool was way ahead of its time and failed to get an instant popularity. But today we know how basic competent it is for our PCs.

The fact is that neither Engelbart’s nor his colleagues got much profit from the invention. SRI later licensed the technology for $40,000 to Apple, which released its first commercial mouse with the Lisa computer in 1983.The mouse patent had a 17-year life span, and in 1987 the technology fell into the public domain meaning Engelbart couldn't collect royalties on the mouse when it was in its widest use.

Engelbart's has also contributed in the development of ARPANet, the government research network that led to the Internet.  

He had won prestigious accolades that include National Medal of Technology and the Turing Award.

Engelbart is survived by Karen O'Leary, his second wife, and his children Gerda, Diana, Christina and Norman. His first wife, Ballard, died in 1997.

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