Your correspondent has been happily using Gutsy Gibbon on a ten-year-old desktop with only 128 megabytes of RAM and a tiny 10 gigabyte hard-drive. When Michael Dell, the boss of Dell Computers, runs Ubuntu on one of his home systems, Linux is clearly doing many things right.
And because it is free, Linux become the operating system of choice for low-end PCs. It started with Nicholas Negroponte, the brains behind the One Laptop Per Child project that aims to deliver computerised education to children in the developing world. His clever XO laptop, costing less than $200, would never have seen the light of day without its clever Linux operating system.
But Mr Negroponte has done more than create one of the world's most ingenious computers. With a potential market measured in the hundreds of millions, he has frightened a lot of big-time computer makers into seeing how good a laptop they can build for less than $500.
All start with a desktop version of Linux. Recent arrivals include the Asus Eee from Taiwan, which lists for $400. The company expects to sell close on four million Eees this financial year. Another Taiwanese maker, Everex, is selling its gPC desktop through Walmart for $199.
When firms are used to buying $1,000 office PCs running Vista Business Edition and loading each with a $200 copy of Microsoft Office, the attractions of a sub-$500 computer using a free operating system like Linux and a free productivity suite like OpenOffice suddenly become very compelling.
And that's not counting the $20,000 or more needed for Microsoft's Exchange and SharePoint server software. Again, Linux provides such server software for free.
Pundits agree: neither Microsoft nor Apple can compete at the new price points being plumbed by companies looking to cut costs. With open-source software maturing fast, Linux, OpenOffice, Firefox, MySQL, Evolution, Pidgin and some 23,000 other Linux applications available for free seem more than ready to fill that gap. By some reckonings, Linux fans will soon outnumber Macintosh addicts. Linus Torvalds should be rightly proud.