Continued to work for two ICL departments. The first was Point-of-sale related, and the second more general 1500 assembler work.
I spent a good deal of 1980 doing unpaid mathematics, although I did contract work in two ICL departments as in 1979. This work was all 1500 based, working in assembler.
Mathematically the J4 construction was completed. Jon Thackray's work on the 2-modular Characters of the McLaughlin group was also of great interest at this time, as he and I had many discussions as to how larger and larger matrices could be handled, or - better - their handling could be avoided altogether. The early concept of "condensation" was discovered at this time, and was used by Jon.