Hi Neal, Many thanks for your information!
Could you write a counter-story/public reply for the Hurd-Wiki? It needn't be long, but it should be available online. Best wishes, Arne Am Mittwoch 13 August 2008 10:04:29 schrieb Neal H. Walfield: > Gernot Heiser recently wrote an article, "Microkernels rule!" for > Embedded.com about microkernels' bad reputation. I fully agree with > the message of his article: operating systems based on microkernel > technology don't necessarily have to be slow and can be made more > robust than their monolithic counterparts. However, Gernot mentions > the Hurd and incorrectly describes its position in history: > > Mach, an OS that was widely used as the basis of systems, ran into > serious performance problems... There were spectacular failures, > none more so than IBM's Workplace OS, which cost the company a cool > two gigabucks... > > Needless to say, the experience with Mach and others created a bit > of an image problem for microkernels (which didn't stop the GNU Hurd > from repeating the mistakes of the past). However, back in 1993, > Jochen Liedtke demonstrated that these performance problems weren't > inherent in the microkernel concept. > > The Hurd did not repeat the errors of past. Work on the Hurd started > in 1990. In GNU's Bulletin January, 1994 [1], you'll find an article > detailing the Hurd's architecture. Workplace OS was conceived in > 1991; it was deemed a failure around 1995. Jochen's article > "Improving IPC by Kernel Design" was published in December 1993. > > Regarding, Workplace OS, its main goals were: machine independence, > multiple personalities, and concurrent operation of personalities [3]. > The last two goals, as far as I am aware, were never a priority in the > development of the Hurd. Further, Workplace OS had already adopted > many second generation microkernel features, for instance, L3's > synchronous IPC. In the major "Observations and Lessons" section of > [3], this is not even mentioned; management, coordination, and focus > are cited as the major problems. > > Finally, the architectural problems that we have identified with Mach > [4] are not related to IPC. The most important are the lack of > resource accounting, and the bad resource management (paging > decisions). Regarding the implementation that we use, the major > problems are unoptimized code (e.g., when evicting a bunch of pages, > Mach always sends them one at a time to the manager), and the decades > old code base which was designed for machines with tens of megabytes > of RAM. > > Neal > > > [0] http://www.embedded.com/columns/guest/208800243 > > [1] http://www.gnu.org/bulletins/bull16.html#SEC13 > > [2] Improving IPC by kernel design > Jochen Liedtke > SOSP December 1993 > http://portal.acm.org/citation.cfm?id=173668.168633 > > [3] Workplace Microkernel and OS: A Case Study > Brett D. Fleisch and Mark Allan A. Co > Software--Practice and Experience > May 1998 > http://portal.acm.org/citation.cfm?id=279869.279875 > > [4] A Critique of the GNU Hurd Multi-server Operating System > Neal H. Walfield and Marcus Brinkmann > ACM SIGOPS Operating Systems Review > July 2007 > http://portal.acm.org/citation.cfm?id=1278901.1278907 -- -- My stuff: http://draketo.de - stories, songs, poems, programs and stuff :) -- Infinite Hands: http://infinite-hands.draketo.de - singing a part of the history of free software. -- Ein Würfel System: http://1w6.org - einfach saubere (Rollenspiel-) Regeln. -- PGP/GnuPG: http://draketo.de/inhalt/ich/pubkey.txt
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