David Howarth's started as a research student at Imperial College, University of London, using the Ferranti Mark 1 at Manchester to handle band structure calculations in solid state physics. He then spent a year at MIT using the Whirlwind system for similar calculations, followed by a period at the Royal Radar Establishment (Malvern), using the TREAC machine for problems in mathematical physics.
In 1960 he became a systems engineer at Ferranti in London, which led to his involvement in the Atlas project and was the leader of the team that produced the Atlas Supervisor, probably the world's first operating systems.
In 1970 he moved into academia taking up a Chair at the Institute of Computer Science at the University of London before moving to become a professor in the Department of Computing at Imperial College.
At the Chilton Atlas Closure, Dave Howarth ran the last program before its closure. Before the final button pushing, Dave Howarth gave an amusing talk concluding by saying that he was about to run the last program on Atlas which was also the very first ever run. The only difference was that he had removed one adjective. He then proceeded to load the paper tape. The final program (without adjective) was - It works - and about time too.