He used all the time he could muster on a heavily burdened computer, and benefited from the APL\360 User's Manual (the book APL Language was not published until March 1975).

After receiving a BSc degree with first class honors in computer science in 1977, Hui worked for two years as a full-time programmer and analyst in the new Edmonton office of IPSA, where his main duty was to support clients in their use of APL time-sharing.

[citation needed] In September 1979, Hui entered the Department of Computer Science at the University of Toronto, and received his MSc in May 1981 with a thesis on "The complexity of some decompositions in matrix algebra.

"[4] After completing his master's degree, Hui worked from 1981 to 1985 as an APL systems analyst and programmer for the Alberta Energy Company in Edmonton.

Hui's work was described at the APL85 conference in a paper, "DESIGN: A Financial Modelling System", written jointly with his supervisor, Fred Appleyard.

Hui left Alberta Energy shortly after being promoted to a non-APL and non-programming position, and was out of work, and had no access to computers, from September 1985 to April 1986.