Peter Donnelly was hired as an APL programmer by Dyadic Systems in 1980, and in 1990 was one of the three employees who bought the company from its owner at the time, Hunting plc. With co-owners John Scholes and Pauline Brand, he helped to manage the company and develop and sell Dyalog APL, and he also originated the Dyalog duck. In 2005, as Gitte Christensen and Morten Kromberg took over executive management, Donnelly went into partial retirement. Now living in Alonissos, he continues part-time work writing Dyalog APL's documentation. In 1995 he and John Scholes received the Iverson Award for their role in creating and promoting Dyalog APL.
I spent most of the time at APL83 behind a curtain coding, because we had problems with the compactor. It’s surprising Pete still has any hair left, with the organising and borrowing of machines, making sure it all arrived and had Unix on it. It was horrific.
With a degree in engineering, Donnelly was hired for his first job at the aero-engine division of Rolls-Royce, where he worked in various departments before learning to program (in FORTRAN, and later PL/I, assembly language, and even self-designed languages) and taking a position in operations research. He left for a similar position in financial modeling at W. H. Smith. Donnelly learned Xerox APL there around 1974, in a one-day course by John Scholes, and immediately began working with the language, even though he had to use the substitute character system as no APL input was available. In 1980, his APL experience led him to join Dyadic Systems as an APL consultant. After John Scholes and Geoff Streeter developed the first version of Dyalog APL from 1981 to 1983, it was Donnelly who promoted it at conferences, visited potential clients, and later worked with APL distributors abroad to market Dyalog. In 1990, he, Scholes, and hardware division director Pauline Brand, fearing for Dyadic's future as an unprofitable subsidiary of Hunting plc, took a loan with their houses as collateral to buy the company. Donnelly managed the business and marketing side of the company as its initially uncertain future gave way to profitability with interest from financial companies and the very successful Windows version of Dyalog.