Although Torvalds has never made any secret of the fact that he drew inspiration from Minix, a 92-page report due to be published on Thursday by the 14-person Alexis de Tocqueville Institution suggests that Minix did not receive the credit it was due.
The study comes not long after several attacks on Linux -- many of them spurred by Microsoft, whose Windows OS competes with Linux. More significantly, it arrives in the midst of a legal attack on Linux by the SCO Group, which argues that Linux violates its Unix copyrights. If proof was shown that Torvalds improperly relied on Tanenbaum's intellectual property, it would only add fuel to SCO's case, but both men emphatically say that this is not the case.
According to the study, it is "highly questionable that Linus, still just a student, with virtually no operating systems development experience," could create an operating system in a matter of months.
"Why are the most brilliant business minds in the history of PC technology, with hundreds of millions of dollars in capital, licensing Unix source code, if it is as simple as writing it from scratch with little help or experience? Is it possible that building a Unix operating system really only takes a few months -- and, oh by the way, you don't even need the source code to do it?" the study asks.
In an email interview, Torvalds disputed the study's conclusions. "Linux never used Minix code... We never credited anybody else's code, because we never used anybody else's code," Torvalds said. But Unix, he said, did provide ideas: "Linux has always credited Unix. There has never been any question about the fact that Linux was very open about taking a lot of good ideas from Unix."
Minix, he said, was simply a platform on top of which Torvalds did his programming work.
The study suggested that Torvalds might have gradually replaced Minix code with Linux but Torvalds denied it. "I didn't 'write the Minix code out of Linux'," Torvalds said. "I was using Minix when I wrote Linux, but that's in the same sense that you are using Windows when you write your columns. Do your articles contain Windows source code because you use Windows to write them?"
On Wednesday, Andrew Tanenbaum waded in in Torvald's defence with a scathing account of his meeting with the author of the report, Ken Brown, who is president of the Alexis de Tocqueville Institution.
Nobody stole anything from anyone, said Tanenbaum. "Brown's remark that people have tried and failed for 30 years to build UNIX-like systems is patent nonsense. Six different people did it independently of one another. In science it is considered important to credit people for their ideas, and I think Linus has done this far less than he should have, but that is quite different from asserting that Linus didn't write Linux. He didn't write CTSS and he didn't write MULTICS and didn't write UNIX and he didn't write MINIX, but he did write Linux. I think Brown owes a number of us an apology."
When the institute announced the pending publication of the report earlier this week -- saying it "directly challenges Linus Torvalds' claim to be the inventor of Linux" -- it immediately drew criticism from open-source advocates who suggested Linux foe Microsoft was behind the report.
Microsoft indeed has provided funding to the Alexis de Tocqueville Institution for five years, a Microsoft representative said, without disclosing how much has been granted. Microsoft funds several public policy institutes, including the American Enterprise Institute, the Center for Strategic and International Studies, the Heritage Foundation, and the Cato Institute, the representative said.
Brown declined to discuss his organisation's funding sources but said there are several and that its research is independent. "I publish what I think and that's it. I don't work for anybody's PR machine," he said.