Hybrid (micro)kernels

By: Tzvetan Mikov (tmikov.delete@this.gmail.com), May 8, 2006 3:41 pm
Room: Moderated Discussions
After todays mention of microkernels on Slashdot, I came across this explanation of "hybrid kernels" in Wikipedia: http://en.wikipedia.org/wiki/Hybrid_kernel

This is the first time I see something on Wikipedia, which I think is blatantly wrong. (You can see my comments in the "talk" page associated with the article).

Anyway, 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.

The article goes to say that a hybrid kernel like NT's is not to be confused with a with monolithic kernels that can load modules like Linux. Again, this seems like nonsense to me - the stable driver ABI (and the closed source) has facilitated creating of many drivers outside of the NT kernel tree, but this is not a conceptual difference. The precise technique of loading a driver/module into the kernel doesn't really matter, if the driver shares the same address space and can have access to kernel structures.

To me the difference between a microkernel and NT (or Linux) is much greater than the differences between NT and Linux, for example.

So, I am not brave enough to edit a page no Wikipedia, but what do you guys thinks ? Am I confused, or is wikipedia wrong ? If it is the latter, should we consider edting it ? (BTW, I am staying away of subjects like which is better, etc - I just want to clarify the definitions)
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TopicPosted ByDate
Hybrid (micro)kernelsTzvetan Mikov2006/05/08 03:41 PM
  Hybrid (micro)kernelsS. Rao2006/05/08 05:14 PM
  Hybrid (micro)kernelsBill Todd2006/05/08 05:16 PM
    Hybrid (micro)kernelsTzvetan Mikov2006/05/08 06:21 PM
      Hybrid (micro)kernelsnick2006/05/08 06:50 PM
      Hybrid (micro)kernelsBill Todd2006/05/09 12:26 AM
        There aren't enough words...Rob Thorpe2006/05/09 01:39 AM
          There aren't enough words...Tzvetan Mikov2006/05/09 02:10 PM
            There aren't enough words...Rob Thorpe2006/05/14 11:25 PM
        Hybrid (micro)kernelsTzvetan Mikov2006/05/09 10:17 AM
          Hybrid (micro)kernelsBill Todd2006/05/09 03:05 PM
  Hybrid (micro)kernelsrwessel2006/05/08 10:23 PM
    Hybrid kernel, not NTRichard Urich2006/05/09 05:03 AM
      Hybrid kernel, not NT_Arthur2006/05/09 06:06 AM
        Hybrid kernel, not NTRob Thorpe2006/05/09 06:40 AM
          Hybrid kernel, not NT_Arthur2006/05/09 07:30 AM
            Hybrid kernel, not NTRob Thorpe2006/05/09 08:07 AM
              Hybrid kernel, not NT_Arthur2006/05/09 08:36 AM
                Linux vs MacOSX peformance, debunked_Arthur2006/05/18 06:30 AM
                  Linux vs MacOSX peformance, debunkedRob Thorpe2006/05/18 07:19 AM
                    Linux vs MacOSX peformance, debunkedAnonymous2006/05/18 11:31 AM
        Hybrid kernel, not NTLinus Torvalds2006/05/09 07:16 AM
          Hybrid kernel, not NTAndi Kleen2006/05/09 01:32 PM
            Hybrid kernel, not NTmyself2006/05/09 02:24 PM
              Hybrid kernel, not NTmyself2006/05/09 02:41 PM
              Hybrid kernel, not NTBrendan2006/05/09 04:26 PM
                Hybrid kernel, not NTLinus Torvalds2006/05/09 07:06 PM
                  Hybrid kernel, not NTBrendan2006/05/13 12:35 AM
                    Hybrid kernel, not NTnick2006/05/13 03:40 AM
                      Hybrid kernel, not NTBrendan2006/05/13 08:48 AM
                        Hybrid kernel, not NTnick2006/05/13 06:41 PM
                          Hybrid kernel, not NTBrendan2006/05/13 08:51 PM
                            Hybrid kernel, not NTnick2006/05/14 04:57 PM
                              Hybrid kernel, not NTBrendan2006/05/14 09:40 PM
                                Hybrid kernel, not NTnick2006/05/14 10:46 PM
                                  Hybrid kernel, not NTBrendan2006/05/15 03:00 AM
                                    Hybrid kernel, not NTrwessel2006/05/15 06:21 AM
                                      Hybrid kernel, not NTBrendan2006/05/15 07:55 AM
                                        Hybrid kernel, not NTLinus Torvalds2006/05/15 08:49 AM
                                          Hybrid kernel, not NTnick2006/05/15 03:41 PM
                                          Hybrid kernel, not NTtony roth2008/01/31 01:20 PM
                                    Hybrid kernel, not NTnick2006/05/15 05:33 PM
                                      Hybrid kernel, not NTBrendan2006/05/16 12:39 AM
                                        Hybrid kernel, not NTnick2006/05/16 01:53 AM
                                          Hybrid kernel, not NTBrendan2006/05/16 04:37 AM
                  Hybrid kernel, not NTAnonymous2008/05/01 09:31 PM
                    Following the structure of the treeMichael S2008/05/02 03:19 AM
                      Following the structure of the treeDean Kent2008/05/02 04:31 AM
                        Following the structure of the treeMichael S2008/05/02 05:02 AM
                        Following the structure of the treeDavid W. Hess2008/05/02 05:48 AM
                          Following the structure of the treeDean Kent2008/05/02 08:14 AM
                            Following the structure of the treeDavid W. Hess2008/05/02 09:05 AM
                              LOL!Dean Kent2008/05/02 09:33 AM
                              Following the structure of the treeanonymous2008/05/02 02:04 PM
                                Following the structure of the treeDean Kent2008/05/02 06:52 PM
                                Following the structure of the treeFoo_2008/05/03 01:01 AM
                                  Following the structure of the treeDavid W. Hess2008/05/03 05:54 AM
                                    Following the structure of the treeDean Kent2008/05/03 09:06 AM
                                      Following the structure of the treeFoo_2008/05/04 12:06 AM
                                        Following the structure of the treeMichael S2008/05/04 12:22 AM
            Hybrid kernel, not NTLinus Torvalds2006/05/09 04:19 PM
              Microkernel Vs Monolithic KernelKernel_Protector2006/05/09 08:41 PM
                Microkernel Vs Monolithic KernelDavid Kanter2006/05/09 09:30 PM
                  Sigh, Stand back, its slashdotting time. (NT)Anonymous2006/05/09 09:44 PM
                  Microkernel Vs Monolithic Kernelblah2006/05/12 07:58 PM
                  Microkernel Vs Monolithic KernelRob Thorpe2006/05/15 12:41 AM
          Hybrid kernel, not NTAnalGuy2006/05/16 02:10 AM
            Theory versus practiceDavid Kanter2006/05/16 11:55 AM
              Distributed algorithmsRob Thorpe2006/05/16 11:53 PM
              Theory versus practiceHoward Chu2006/05/17 01:54 AM
                Theory versus practiceJS2006/05/17 03:29 AM
          Play online poker, blackjack !!! Gamezonex2007/08/16 12:49 PM
  Hybrid (micro)kernelsphilt2006/05/14 08:15 PM
    Hybrid (micro)kernelsLinus Torvalds2006/05/15 07:20 AM
      Hybrid (micro)kernelsLinus Torvalds2006/05/15 10:56 AM
        Hybrid (micro)kernelsRob Thorpe2006/05/16 12:22 AM
          Hybrid (micro)kernelsrwessel2006/05/16 10:23 AM
            Hybrid (micro)kernelsRob Thorpe2006/05/16 11:43 PM
              Hybrid (micro)kernelsrwessel2006/05/17 12:33 AM
                Hybrid (micro)kernelsRob Thorpe2006/05/19 06:51 AM
                  Hybrid (micro)kernelsrwessel2006/05/19 11:27 AM
      Hybrid (micro)kernelstechIperson2006/05/15 12:25 PM
      Hybrid (micro)kernelsmas2006/05/15 04:17 PM
        Hybrid (micro)kernelsLinus Torvalds2006/05/15 04:39 PM
          Hybrid (micro)kernelsColonel Kernel2006/05/15 08:17 PM
            Hybrid (micro)kernelsWink Saville2006/05/15 09:31 PM
              Hybrid (micro)kernelsLinus Torvalds2006/05/16 09:08 AM
                Hybrid (micro)kernelsWink Saville2006/05/16 08:55 PM
          Hybrid (micro)kernelsrwessel2006/05/16 10:31 AM
            Hybrid (micro)kernelsLinus Torvalds2006/05/16 11:00 AM
        Hybrid (micro)kernelsBrendan2006/05/16 12:36 AM
        Hybrid (micro)kernelsPaul Elliott2006/09/03 07:44 AM
          Hybrid (micro)kernelsRob Thorpe2006/09/04 08:25 AM
      Hybrid (micro)kernelsphilt2006/05/15 11:55 PM
        Hybrid (micro)kernelspgerassi2007/08/16 06:41 PM
  Another questionable entry on Wikipedia?Chung Leong2006/05/18 09:33 AM
  Hybrid (micro)kernelsisrael2006/05/20 03:25 AM
    Hybrid (micro)kernelsRob Thorpe2006/05/22 07:35 AM
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