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Andy Tanenbaum on 'Who Wrote Linux'
Andy Tanenbaum writes "Ken Brown has just released a book on open source code. In it, he claims (1) to have interviewed me, and (2) that Linus Torvalds didn't write Linux. I think Brown is batting .500, which is not bad for an amateur (for people other than Americans, Japanese, and Cubans, this is an obscure reference to baseball). Since I am one of the principals in this matter, I thought it might be useful for me to put my 2 eurocents' worth into the hopper. If you were weren't hacking much code in the 1980s, you might learn something." Tanenbaum's description of the interview process with Brown is classic. See also Slashdot's original story and Linus' reply.
Some Notes on the "Who wrote Linux" Kerfuffle, Release 1.1
Background
The history of UNIX and its various children and grandchildren has been in the news recently as a result of a book from the Alexis de Tocqueville Institution. Since I was involved in part of this history, I feel I have an obligation to set the record straight and correct some extremely serious errors. But first some background information.
Ken Brown, President of the Alexis de Tocqueville Institution, contacted me in early March. He said he was writing a book on the history of UNIX and would like to interview me. Since I have written 15 books and have been involved in the history of UNIX in several ways, I said I was willing to help out. I have been interviewed by many people for many reasons over the years, and have been on Dutch and US TV and radio and in various newspapers and magazines, so I didn't think too much about it.
Brown flew over to Amsterdam to interview me on 23 March 2004. Apparently I was the only reason for his coming to Europe. The interview got off to a shaky start, roughly paraphrased as follows:
AST: "What's the Alexis de Tocqueville Institution?"
KB: We do public policy work
AST: A think tank, like the Rand Corporation?
KB: Sort of
AST: What does it do?
KB: Issue reports and books
AST: Who funds it?
KB: We have multiple funding sources
AST: Is SCO one of them? Is this about the SCO lawsuit?
KB: We have multiple funding sources
AST: Is Microsoft one of them?
KB: We have multiple funding sources
He was extremely evasive about why he was there and who was funding him. He just kept saying he was just writing a book about the history of UNIX. I asked him what he thought of Peter Salus' book, A Quarter Century of UNIX. He'd never heard of it! I mean, if you are writing a book on the history of UNIX and flying 3000 miles to interview some guy about the subject, wouldn't it make sense to at least go to amazon.com and type "history unix" in the search box, in which case Salus' book is the first hit? For $28 (and free shipping if you play your cards right) you could learn an awful lot about the material and not get any jet lag. As I sooned learned, Brown is not the sharpest knife in the drawer, but I was already suspicious. As a long-time author, I know it makes sense to at least be aware of what the competition is. He didn't bother.
UNIX and Me
I didn't think it odd that Brown would want to interview me about the history of UNIX. There are worse people to ask. In the late 1970s and early 1980s, I spent several summers in the UNIX group (Dept. 1127) at Bell Labs. I knew Ken Thompson, Dennis Ritchie, and the rest of the people involved in the development of UNIX. I have stayed at Rob Pike's house and Al Aho's house for extended periods of time. Dennis Ritchie, Steve Johnson, and Peter Weinberger, among others have stayed at my house in Amsterdam. Three of my Ph.D. students have worked in the UNIX group at Bell Labs and one of them is a permanent staff member now.
Oddly enough, when I was at Bell Labs, my interest was not operating systems, although I had written one and published a paper about it (see "Software - Practice & Experience," vol. 2, pp. 109-119, 1973). My interest then was compilers, since I was the chief designer of the the Amsterdam Compiler Kit (see Commun. of the ACM, vol. 26, pp. 654-660, Sept. 1983.). I spent some time there discussing compilers with Steve Johnson, networking with Greg Chesson, writing tools with Lorinda Cherry, and book authoring with Brian Kernighan, among many others. I also became friends with the other "foreigner," there, Bjarne Stroustrup, who would later go on to design and implement C++.
In short, although I had nothing to do with the development of the original UNIX, I knew all the people involved and much of the history quite well. Furthermore, my contact with the UNIX group at Bell Labs was not a secret; I even thanked them all for having me as a summer visitor in the preface to the first editio
Some Notes on the "Who wrote Linux" Kerfuffle, Release 1.1
Background
The history of UNIX and its various children and grandchildren has been in the news recently as a result of a book from the Alexis de Tocqueville Institution. Since I was involved in part of this history, I feel I have an obligation to set the record straight and correct some extremely serious errors. But first some background information.
Ken Brown, President of the Alexis de Tocqueville Institution, contacted me in early March. He said he was writing a book on the history of UNIX and would like to interview me. Since I have written 15 books and have been involved in the history of UNIX in several ways, I said I was willing to help out. I have been interviewed by many people for many reasons over the years, and have been on Dutch and US TV and radio and in various newspapers and magazines, so I didn't think too much about it.
Brown flew over to Amsterdam to interview me on 23 March 2004. Apparently I was the only reason for his coming to Europe. The interview got off to a shaky start, roughly paraphrased as follows:
AST: "What's the Alexis de Tocqueville Institution?"
KB: We do public policy work
AST: A think tank, like the Rand Corporation?
KB: Sort of
AST: What does it do?
KB: Issue reports and books
AST: Who funds it?
KB: We have multiple funding sources
AST: Is SCO one of them? Is this about the SCO lawsuit?
KB: We have multiple funding sources
AST: Is Microsoft one of them?
KB: We have multiple funding sources
He was extremely evasive about why he was there and who was funding him. He just kept saying he was just writing a book about the history of UNIX. I asked him what he thought of Peter Salus' book, A Quarter Century of UNIX. He'd never heard of it! I mean, if you are writing a book on the history of UNIX and flying 3000 miles to interview some guy about the subject, wouldn't it make sense to at least go to amazon.com and type "history unix" in the search box, in which case Salus' book is the first hit? For $28 (and free shipping if you play your cards right) you could learn an awful lot about the material and not get any jet lag. As I sooned learned, Brown is not the sharpest knife in the drawer, but I was already suspicious. As a long-time author, I know it makes sense to at least be aware of what the competition is. He didn't bother.
UNIX and Me
I didn't think it odd that Brown would want to interview me about the history of UNIX. There are worse people to ask. In the late 1970s and early 1980s, I spent several summers in the UNIX group (Dept. 1127) at Bell Labs. I knew Ken Thompson, Dennis Ritchie, and the rest of the people involved in the development of UNIX. I have stayed at Rob Pike's house and Al Aho's house for extended periods of time. Dennis Ritchie, Steve Johnson, and Peter Weinberger, among others have stayed at my house in Amsterdam. Three of my Ph.D. students have worked in the UNIX group at Bell Labs and one of them is a permanent staff member now.
Oddly enough, when I was at Bell Labs, my interest was not operating systems, although I had written one and published a paper about it (see "Software - Practice & Experience," vol. 2, pp. 109-119, 1973). My interest then was compilers, since I was the chief designer of the the Amsterdam Compiler Kit (see Commun. of the ACM, vol. 26, pp. 654-660, Sept. 1983.). I spent some time there disc
...and to make them perform reasonably well, both of these have hacks (server collocation, etc.) that remove the whole reason for microkernels in the first place.
Don't fall for the hype.
On the other hand, QNX is actually pretty true to the concept.
In a kernel there is a lot of interaction between the various parts. In a monolithic kernel these interactions are performed by simple subroutine calls and manipulation of shared data. In a microkernel these interactions require a more complex switch between tasks, and message passing. In exchange, you get better protection of one part from the others, which makes tracking down bugs quicker.
John Sauter (J_Sauter@Empire.Net)
AST lists several independently developed systems of equivalent complexity to Mixix 1.0 / System 7. Here are a couple more I found:
OMU (6809 processor, ported to 68000) roughly system 7 but only single user, integrated shell.
http://tallyho.bc.nu/~steve/omu.html
UZI (Z80 processor, ported to 180, 280) roughly system 7: multitasking
http://www.dougbraun.com/uzi.html
my first reaction to this attack was, 'who the f### is Ken Brown? as they taught me back in school, 'always consider the source' --if this guy's attacking Linux, he'd better have some solid credentials in the computer industry, right? well, all it took was a Google search, and the first link I hit told me all i need to know: Anti-Open Source lobbyists need love, too Friday October 25, 2002 - [ 03:00 PM GMT ] Topics: Migration - By Robin "Roblimo" Miller - I felt bad for Ken Brown of the Alexis De Toqueville Institution (AdTI) last week... http://www.newsforge.com/business/02/10/25/056218. shtml?tid=19
thanks to Roblimo, we have a first-hand account of Ken Brown's shameless FUD-ing, back in 2002--read this link for a cuttingly funny look at Mr. Browns earlier efforts;>
you gotta love the 'thousands of eyeballs' that are working on our side--it more than offsets what M$ gets from spreading it's dirty money around...
-DWitt
ps. methinks Brown's IP has just gone down the tubes--thank you very much Andy Tanenbaum!
I read the article from the Groklaw link before it showed up on /. Tanenbaum says that at least five different people single handedly wrote a UNIX-like kernel and that Linus clearly wrote Linux. He also says that Brown, the person who interviewed him, was completely clueless and obviously pushing an agenda.
The bitter part comes in the last couple of paragraphs, where he takes the opportunity to say that Linus was a misguided kid who should have paid more attention in class such that he would have seen the obvious superiority of a microkernel over a macrokernel. But he's quick to point out that he and Linus are not enemies.
"The legitimate powers of government extend only to such acts as are injurious to others." Thomas Jefferson.
Windoz had a microkernel in the NT 3.51 days. It is way far from a microkernel today. There are some info about this on the NT 4 resource kit documentation.
cheers.
``If a program can't rewrite its own code, what good is it?'' - Mel
To summarize, let me call the part that securely multiplexes hardware the "kernel".
- Monolithic makes drivers share address space with the "kernel".
- With Microkernel, "kernel", drivers, filesystems, applications, etc each get their own address spaces.
- Exokernel makes drivers share address space with applications. (Hopefully, filesystems get their own process and address space.)
As you can see, as soon as you start partitioning applications into separate processes for security and robustness, the distinction between Exokernel and Microkernel becomes rather vague. The advantage of the Exokernel or VM approach is that you get the flexibility of keeping things like filesystems in a separate process for security and robustness, and things like video drivers in the same address space for performance. You might even have an X server as a separate process, but still allow full screen mode games that directly call the driver libraries for performance.IBM's VM was never that popular in its raw "Exokernel" mode with drivers in application space. However, it is still hugely popular as a way to run multiple Operating Systems as the "applications". Your mainframe can securely run multiple instances of S/390 Linux and traditional mainframe systems together.
Matt Loney of ZDNet UK is covering the story, including Andy Tanenbaum's two Euro-cents here. I don't think anyone at AdTI, least of all Ken Brown, is going to be living off royalties any time soon - "falls at the starting gate" indeed. ZD even mention AdTI's ties to Microsoft least there be any doubt, which is nice of them. :)
UNIX? They're not even circumcised! Savages!
After seeing all the responses yesterday, I think I have a better idea of Ken Brown's motivation in coming to see me and also his motivation in writing the book. If you are curious, take a look at
www.cs.vu.nl/~ast/brown/followup
Andy Tanenbaum