Hybrid (micro)kernels

By: Bill Todd (billtodd.delete@this.metrocast.net), May 8, 2006 6:16 pm
Room: Moderated Discussions
Tzvetan Mikov (tmikov@gmail.com) on 5/8/06 wrote:


the article describes NT's kernel as a "hybrid kernel" sharing architectural
>concepts or mechanisms with microkernel designs such as "message passing" and "migration
>of "non-essential" code into user space". This strikes me as rubbish for two reasons:
>- In NT messages (IRPs) are used for implementing asynchronous execution, which
>is essentially an implementation detail and has nothing to do with microkernels.
>As a matter of fact IRPs are so fragile, that in a sense they achieve an effect opposite to a microkernel.
>- All essential subsystems in NT are implemented in the kernel - filesystems, usb,
>networking, etc. Of course there are components in user space which are considered
>part of the OS (what isn't in Windows?), but such components are implented in user space in all OS-es.

Just dropped by to see what the reaction to SGI's unfortunate predicament was, and happened upon your post.

Understanding NT's characterization as micro-kernel-related probably requires knowing something about how it evolved. In the beginning, it had (at least) three distinct personalities: Windows, POSIX, and OS/2 (IIRC). Each personality (and much of the graphics system as well) was implemented as a user-space service which applications needing it accessed via message passing (IRPs are kernel constructs which have nothing to do with the message-passing facilities being referred to).

Graphics support got inhaled into the kernel proper after performance became an issue. POSIX and OS/2 support withered and the Windows 'personality' became little more than a set of user-mode library stub interfaces rather than a separate protected user-mode server.

Even in the beginning NT's kernel contained considerably more than a classic micro kernel, but it at least had *some* resemblance to one.

- bill
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TopicPosted ByDate
Hybrid (micro)kernelsTzvetan Mikov2006/05/08 04:41 PM
  Hybrid (micro)kernelsS. Rao2006/05/08 06:14 PM
  Hybrid (micro)kernelsBill Todd2006/05/08 06:16 PM
    Hybrid (micro)kernelsTzvetan Mikov2006/05/08 07:21 PM
      Hybrid (micro)kernelsnick2006/05/08 07:50 PM
      Hybrid (micro)kernelsBill Todd2006/05/09 01:26 AM
        There aren't enough words...Rob Thorpe2006/05/09 02:39 AM
          There aren't enough words...Tzvetan Mikov2006/05/09 03:10 PM
            There aren't enough words...Rob Thorpe2006/05/15 12:25 AM
        Hybrid (micro)kernelsTzvetan Mikov2006/05/09 11:17 AM
          Hybrid (micro)kernelsBill Todd2006/05/09 04:05 PM
  Hybrid (micro)kernelsrwessel2006/05/08 11:23 PM
    Hybrid kernel, not NTRichard Urich2006/05/09 06:03 AM
      Hybrid kernel, not NT_Arthur2006/05/09 07:06 AM
        Hybrid kernel, not NTRob Thorpe2006/05/09 07:40 AM
          Hybrid kernel, not NT_Arthur2006/05/09 08:30 AM
            Hybrid kernel, not NTRob Thorpe2006/05/09 09:07 AM
              Hybrid kernel, not NT_Arthur2006/05/09 09:36 AM
                Linux vs MacOSX peformance, debunked_Arthur2006/05/18 07:30 AM
                  Linux vs MacOSX peformance, debunkedRob Thorpe2006/05/18 08:19 AM
                    Linux vs MacOSX peformance, debunkedAnonymous2006/05/18 12:31 PM
        Hybrid kernel, not NTLinus Torvalds2006/05/09 08:16 AM
          Hybrid kernel, not NTAndi Kleen2006/05/09 02:32 PM
            Hybrid kernel, not NTmyself2006/05/09 03:24 PM
              Hybrid kernel, not NTmyself2006/05/09 03:41 PM
              Hybrid kernel, not NTBrendan2006/05/09 05:26 PM
                Hybrid kernel, not NTLinus Torvalds2006/05/09 08:06 PM
                  Hybrid kernel, not NTBrendan2006/05/13 01:35 AM
                    Hybrid kernel, not NTnick2006/05/13 04:40 AM
                      Hybrid kernel, not NTBrendan2006/05/13 09:48 AM
                        Hybrid kernel, not NTnick2006/05/13 07:41 PM
                          Hybrid kernel, not NTBrendan2006/05/13 09:51 PM
                            Hybrid kernel, not NTnick2006/05/14 05:57 PM
                              Hybrid kernel, not NTBrendan2006/05/14 10:40 PM
                                Hybrid kernel, not NTnick2006/05/14 11:46 PM
                                  Hybrid kernel, not NTBrendan2006/05/15 04:00 AM
                                    Hybrid kernel, not NTrwessel2006/05/15 07:21 AM
                                      Hybrid kernel, not NTBrendan2006/05/15 08:55 AM
                                        Hybrid kernel, not NTLinus Torvalds2006/05/15 09:49 AM
                                          Hybrid kernel, not NTnick2006/05/15 04:41 PM
                                          Hybrid kernel, not NTtony roth2008/01/31 02:20 PM
                                    Hybrid kernel, not NTnick2006/05/15 06:33 PM
                                      Hybrid kernel, not NTBrendan2006/05/16 01:39 AM
                                        Hybrid kernel, not NTnick2006/05/16 02:53 AM
                                          Hybrid kernel, not NTBrendan2006/05/16 05:37 AM
                  Hybrid kernel, not NTAnonymous2008/05/01 10:31 PM
                    Following the structure of the treeMichael S2008/05/02 04:19 AM
                      Following the structure of the treeDean Kent2008/05/02 05:31 AM
                        Following the structure of the treeMichael S2008/05/02 06:02 AM
                        Following the structure of the treeDavid W. Hess2008/05/02 06:48 AM
                          Following the structure of the treeDean Kent2008/05/02 09:14 AM
                            Following the structure of the treeDavid W. Hess2008/05/02 10:05 AM
                              LOL!Dean Kent2008/05/02 10:33 AM
                              Following the structure of the treeanonymous2008/05/02 03:04 PM
                                Following the structure of the treeDean Kent2008/05/02 07:52 PM
                                Following the structure of the treeFoo_2008/05/03 02:01 AM
                                  Following the structure of the treeDavid W. Hess2008/05/03 06:54 AM
                                    Following the structure of the treeDean Kent2008/05/03 10:06 AM
                                      Following the structure of the treeFoo_2008/05/04 01:06 AM
                                        Following the structure of the treeMichael S2008/05/04 01:22 AM
            Hybrid kernel, not NTLinus Torvalds2006/05/09 05:19 PM
              Microkernel Vs Monolithic KernelKernel_Protector2006/05/09 09:41 PM
                Microkernel Vs Monolithic KernelDavid Kanter2006/05/09 10:30 PM
                  Sigh, Stand back, its slashdotting time. (NT)Anonymous2006/05/09 10:44 PM
                  Microkernel Vs Monolithic Kernelblah2006/05/12 08:58 PM
                  Microkernel Vs Monolithic KernelRob Thorpe2006/05/15 01:41 AM
          Hybrid kernel, not NTAnalGuy2006/05/16 03:10 AM
            Theory versus practiceDavid Kanter2006/05/16 12:55 PM
              Distributed algorithmsRob Thorpe2006/05/17 12:53 AM
              Theory versus practiceHoward Chu2006/05/17 02:54 AM
                Theory versus practiceJS2006/05/17 04:29 AM
          Play online poker, blackjack !!! Gamezonex2007/08/16 01:49 PM
  Hybrid (micro)kernelsphilt2006/05/14 09:15 PM
    Hybrid (micro)kernelsLinus Torvalds2006/05/15 08:20 AM
      Hybrid (micro)kernelsLinus Torvalds2006/05/15 11:56 AM
        Hybrid (micro)kernelsRob Thorpe2006/05/16 01:22 AM
          Hybrid (micro)kernelsrwessel2006/05/16 11:23 AM
            Hybrid (micro)kernelsRob Thorpe2006/05/17 12:43 AM
              Hybrid (micro)kernelsrwessel2006/05/17 01:33 AM
                Hybrid (micro)kernelsRob Thorpe2006/05/19 07:51 AM
                  Hybrid (micro)kernelsrwessel2006/05/19 12:27 PM
      Hybrid (micro)kernelstechIperson2006/05/15 01:25 PM
      Hybrid (micro)kernelsmas2006/05/15 05:17 PM
        Hybrid (micro)kernelsLinus Torvalds2006/05/15 05:39 PM
          Hybrid (micro)kernelsColonel Kernel2006/05/15 09:17 PM
            Hybrid (micro)kernelsWink Saville2006/05/15 10:31 PM
              Hybrid (micro)kernelsLinus Torvalds2006/05/16 10:08 AM
                Hybrid (micro)kernelsWink Saville2006/05/16 09:55 PM
          Hybrid (micro)kernelsrwessel2006/05/16 11:31 AM
            Hybrid (micro)kernelsLinus Torvalds2006/05/16 12:00 PM
        Hybrid (micro)kernelsBrendan2006/05/16 01:36 AM
        Hybrid (micro)kernelsPaul Elliott2006/09/03 08:44 AM
          Hybrid (micro)kernelsRob Thorpe2006/09/04 09:25 AM
      Hybrid (micro)kernelsphilt2006/05/16 12:55 AM
        Hybrid (micro)kernelspgerassi2007/08/16 07:41 PM
  Another questionable entry on Wikipedia?Chung Leong2006/05/18 10:33 AM
  Hybrid (micro)kernelsisrael2006/05/20 04:25 AM
    Hybrid (micro)kernelsRob Thorpe2006/05/22 08:35 AM
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