Software Engineer

• Employed on a casual basis in July 1985 as a Software Engineer. Rational Research was the research and development subsidiary of Thomas Clark & Sons, and built security access and environmental control systems.
• Each motherboard in the system ran a proprietary, in-house real time multi-tasking operating system written in C and 8088 assembler, plus a control program written in C, with the motherboards connected to one another over a proprietary network.

What I built

• The door access control program, which validates access when a magnetic key is inserted into a key reader, against an access control list held in memory.
• The lift security control program.
• Components of the proprietary operating system itself: the diagnostic interface, which lets an RS-232 terminal connected to a motherboard change system parameters and monitor system status, and a machine language monitor for interactive real time debugging of the operating system and the control programs.