There aren't enough words...

By: Tzvetan Mikov (tmikov.delete@this.gmail.com), May 9, 2006 2:10 pm
Room: Moderated Discussions
Rob Thorpe () on 5/9/06 wrote:
---------------------------
>
>The problem with this issue is that there aren't enough terms of description.
>It is most realistic to speak about OS kernel by their complexity and their level
>of coupling. Even speaking of "micro", "hybrid" and "monolithic" doesn't go far enough.
>
>Taking an OS to look like this:
>
>Hardware
>|
>Hardware interfaces (ie drivers) (layer D)
>|
>Allocation of hardware to software (layer K)
>|
>Interfaces to user software (layer I)
>|
>User software (layer S)
>
>In a classic microkernel hardware interfaces, drivers, layer D, live outside the
>kernel. Only what I have labelled layer K truely lives in kernel. And then only
>part of that, since layer K includes filesystems which live can live in userspace.
>
>This kind of perspective allows you to write down clearly how many systems work. (Using F to represent the filesystem)
>
>F.e.g.
>

>In kernel User
>Linux D, K, F, some of I S, some of I
>NT4< D, K, F S, I
>NT4> D, K, F, some of I S, some of I
>QNX K D, S, I, F
>Hurd D, K, some of I S, F, some of I
>OSX D, K, F, some of I S, some of I
>

>
>I'm not too sure I've described the more obscure system accurately. My ranking
>of OSX is probably controversial. But since the microkernel can't live without
>the BSD service there is no real sense (speaking of reliability) in saying that the BSD parts live outside the kernel.
>
>Even this ignores loads of other things, SysV Unix for example had a monolithic
>kernel like Linux. But it was only ~6000 lines long, Linux is nearly a thousand times longer.
>
>Anyway, it certainly isn't clear from the table above which deserve to be called hybrid.

I'd say that Hurd looks like a hybrid from your diagram.

About the "I" (Interfaces to user software) - I don't think the distrinction is clearcut in any OS. It doesn't matter whether the kernel's "native" semantics map better to POSIX or Win32. If I run Java or Wine, the entire "I" is in user mode, isn't it ? If not, what exactly do you mean by "I" ?

(I guess this may turn into a philosophical discussion, but so what ?)

< Previous Post in ThreadNext Post in Thread >
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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