The licence under which it is released - the source code is available to the skilled professional who can manipulate it as he needs - makes this possible. Those changes get back into the community if the pro in question decides to sell what he has devised. And so it goes.

Despite this flexibility, it's not often that one hears of the operating system being used in secure facilities by government organisations. Hence I was pleasantly surprised to hear that a locked-down version of the Knoppix distribution is being used at a remand centre close to Melbourne.

The installation of 120 PCs running what the supplier - Melbourne FOSS company Cybersource - calls TrimClient took place about eight months ago after a trial of about six months.

Ron Fabre, product and service manager of the company, says that, given the nature of the facility, there is no internet access needed on any of the machines. The machines all boot off a server and there are different images called up depending on the nature of the user - juveniles get a different set of applications compared to adults.

The images are centrally managed and tweaked as needed, Fabre says. With something of an air of triumphalism he said that the tech support at the centre only needed to spend about 10 minutes providing desktop support for the inmates over the eight months.