Bill Gates has revealed how he used to keep tabs on his employees by memorising all of their number plates to see when they were arriving and leaving the office.
The Microsoft co-founder gave an insight into his early years as a boss when the company was in its infancy during the late 70s, employing only handful of people compared to thousands today.
The billionaire, known today for his mild manner and philanthropy, was a much harder figure in the early years of his career, where he was regarded as a hard negotiator and demanding boss.
In an interview for the BBC's Desert Island Discs broadcast on Monday, Gates admitted being "fanatical about work" in Microsoft's early days, sometimes to the misfortune of coworkers.
"I had to be a little careful not to try and apply my standards to how hard they worked," he said.
"You know, I knew everyone's licence plates so I could look out in the parking lot and see when people coming in, when people were leaving.
Eventually I had to loosen up as the company got to a reasonable size."
He spoke of his relationship with Apple founder Steve Jobs. He said: "For some periods we were complete allies working together. Sometimes he would be tough on you, sometimes he would be very encouraging. And he got really great work out of people."