Wheeler's contributions to the field included work on the
Electronic Delay Storage Automatic Calculator (EDSAC) in the 1950s and the
Burrows–Wheeler transform (published 1994). Along with
Maurice Wilkes and
Stanley Gill, he is credited with the invention around 1951 of the
subroutine (which they referred to as the
closed subroutine), and gave the first explanation of how to design software libraries; (However,
Turing had discussed subroutines in a paper of 1945 on design proposals for the NPL
ACE, going so far as to invent the concept of a return address stack.) He was responsible for the implementation of the
CAP computer, the first to be based on security capabilities. In
cryptography, he was the designer of
WAKE and the co-designer of the
TEA and
XTEA encryption algorithms together with
Roger Needham. In 1950, with Maurice Wilkes, he used EDSAC to solve a
differential equation relating to
gene frequencies in a paper by
Ronald Fisher. This represents the first use of a computer for a problem in the field of
biology. He became a
Fellow of
Darwin College, Cambridge in 1964 and formally retired in 1994, although he continued to be an active member of the
University of Cambridge Computer Laboratory until his death. == Personal life ==