Evi Nemeth, whose work on Unix and Linux, helped develop the languages behind the modern data bases is missing at sea and presumed dead.

Nemeth, 73, worked with Apple co-founder Steve Wozniak to established an IT scholarship programme, but is better known for her books on Unix and Linux.

Nemeth was among seven people cruising around New Zealand on an 85-year-old schooner yacht called the Nina. After a big storm, the boat was reported missing. New Zealand authorities spent days searching and have officially have called off rescue efforts. She was a retired professor from the University of Colorado at Boulder and an experienced sailor.

Besides working with Woz and her books, she also worked on some of the first systems that measure Internet traffic, and organised an international curriculum to train future Internet engineers