Ubuntu founder Mark Shuttleworth has admitted that he spends a significant sum of his own money developing the Linux distribution.
"Ubuntu is expensive," he said, in an interview with German news site Heise, published on Monday. "The distribution costs me a few million dollars a year."
Shuttleworth added that he is unconcerned about the cost, as Linux helped him make his money.
"I can pay, however, because ten years ago when I was still studying at the University of Cape Town in South Africa... Linux allowed me to compete with the best companies in the world, without any obstacles between me and success. That made me a billionaire; so I could fly into space and do many other wonderful things," Shuttleworth said.
Shuttleworth made much of his money from Thawte Consulting, a company that he founded in 1995 during his final year at university. The company, which specialised in digital certificates and Internet security, was bought by VeriSign in December 1999 for 3.5bn rand (£310m).
The main reasons for creating Ubuntu was to help other people and to improve the quality of desktop operating systems, Shuttleworth claimed in the interview.
"I would like to give something back — I would like to help level the playing field for other people as well. And I believe that in the field of desktop operating systems the bar should be set somewhat higher," he said.
Although the Ubuntu distribution is less than two years old, it has risen in popularity among the Linux community and has won a number of awards from technology magazines and conferences, including a ZDNet UK Editor's choice award, and an accolade as the best Linux distribution for small business.