Gerald Ratzer was born in England in 1942. He graduated from Glasgow University in 1963 and went on to do a Post Graduate diploma in Numerical Analysis and Computing at Cambridge University. He came to Canada in 1964 as McGill University's first graduate student in computer science and graduated with a M.Sc. in Computer Science in 1966. He was appointed as an assistant professor in 1966 at McGill and became a founding member of the School of Computer Science in 1970. He became an associate professor in 1973 and a full professor in 1998. He served as Faculty representative to the Senate in 1995 and was the chair or member of various committees in Senate, the Faculty of Engineering and Graduate faculty related to computers. He was the chief executive officer of McGill Systems Inc. (MSI). MSI sought software projects from the University that could be commercially developed.

He won several awards including NSERC and Conference Board of Canada Synergy Award and the Royal Bank Teaching Innovation Award. In 1987 he received a CIDA Grant for a Computer Assisted Learning program at the University of Zimbabwe and in 1993 a $1.2 million Precarn PERK team grant on the Parallel Procession of Spatial Data involving ATS, DREV and CRIM. He consulted in air traffic control simulation, computer assisted learning software, and systems analysis. His chief projects were air traffic control models for ATS Aerospace of St. Bruno, Quebec (1980-1998), and NAV Canada of Ottawa (1998) as well as software development for Hydro Quebec (Symbl project) to locate telecommunication facilities using the production of software named RadioCAD.

He produced more than 20 papers and the following books, A FORTRAN Course, 1975; FORTRAN 77 Course, 1979, 1986; Micros to SuperMicros: An Overview, 1986; FORTRAN 90 and Algorithms, 1995; and FORTRAN 90, C and Algorithms, 1996, 2002.

Ratzer taught courses on computer languages and operating systems, computers in engineering and microcomputers.