Don was mainly famous for writing COCOA, (word COunt and COncordance generation on the Atlas computer).
Don Russell followed Bob Hopgood and Malcolm Bird in spending a sabbatical year at Carnegie-Mellon University (previously Carnegie Tech). There he worked on the BLISS language. This was designed for writing production software systems for the PDP-10: compilers, operating systems, etc. the main design goal was to produce highly efficient object code, to allow access to all relevant hardware features of the host machine, and to provide a rational means by which to cope with the evolutionary nature of systems programs. A major feature which contributed to these goals was the representation of data structures in terms of the access algorithm for elements of the structure.
See William A, Wulf, D. B. Russel and A. Nico Habermann, Bliss: a language for systems programming, CACM, 14, (12), 780-790 (1971).