Tanenbaum–Torvalds debate
Tanenbaum, the creator of Minix, began the debate in 1992 on the Usenet discussion group comp.os.minix, arguing that microkernels are superior to monolithic kernels and therefore Linux was, even in 1992, obsolete.
[2] While the debate initially started out as relatively moderate, with both parties involved making only banal statements about kernel design, it grew progressively more detailed and sophisticated with every round of posts.
[1] While he initially did not go into great technical detail to explain why he felt that the microkernel design was better, he did suggest that it was mostly related to portability, arguing that the Linux kernel was too closely tied to the x86 line of processors to be of any use in the future, as this architecture would be superseded by then.
Furthermore, he mentioned how he developed Linux specifically for the Intel 80386 because it was partly intended as a learning exercise for Torvalds himself; while he conceded that this made the kernel itself less portable than MINIX, he asserted that this was an acceptable design principle, as it made the application programming interface simpler and more portable.
He noted that even though Linux was free, it wouldn't be a viable choice for his students, as they would not be able to afford the expensive hardware required to run it, and that MINIX could be used on "a regular 4.77 MHz PC with no hard disk."
To this, Kevin Brown, another user of the Usenet group, replied that Tanenbaum should not complain about Linux's ties to the 386 architecture, as it was the result of a conscious choice rather than lack of knowledge about operating system design, stating "... an explicit design goal of Linux was to take advantage of the special features of the 386 architecture.
He stated that the Linux kernel would eventually fall out of style as hardware progressed, due to it being so closely tied to the 386 architecture.
[4] Torvalds attempted to end the discussion at that point, stating that he felt he should not have overreacted to Tanenbaum's initial statements, and that he was composing a personal email to him to apologise.
Kevin Brown called it vaporware, and stated that Linux would likely benefit from the x86 architecture which would continue to be common and become more accessible to a general audience.
This was a prelude to the pending publication of a book by Brown titled Samizdat: And Other Issues Regarding the 'Source' of Open Source Code.
Tanenbaum published a strong rebuttal, defending Torvalds,[9] and in a follow-up wrote: I would like to close by clearing up a few misconceptions and also correcting a couple of errors.
After AT&T forbade teaching from John Lions' book, I decided to write a UNIX-like system for my students to play with.
[10] This subject was revisited in 2006 after Tanenbaum wrote a cover story for Computer magazine titled "Can We Make Operating Systems Reliable and Secure?".
[13] Torvalds posted a rebuttal of Tanenbaum's arguments via an online discussion forum,[14] and several technology news sites began reporting the issue.
[15] This prompted Jonathan S. Shapiro (primary developer of the EROS microkernel) to respond that most of the field-proven reliable and secure computer systems use a more microkernel-like approach.
As a response to this, Tanenbaum wrote an open letter to Intel claiming MINIX to be "the most widely used computer operating system in the world".
