4 ms·

I am 100% on the side of Linus Torvalds when it comes to microkernels.[0] I will concede that in some instances a microkernel may outperform a monolithic kerne

I am 100% on the side of Linus Torvalds when it comes to microkernels.[0] I will concede that in some instances a microkernel may outperform a monolithic kernel in stability or performance or both. I am not the least bit excited about any progress made in microkernels, I feel that it can only result in much more closed systems that are easier to implement in ways that make them harder to modify. This is why I wish for Hurd to continue to fail. [0]: http://www.oreilly.com/openbook/opensources/book/appa.html http://www.oreilly.com/openbook/opensources/book/appa.html

PuercoPop 11y ago
I'm confused, I understand you think the Hurd is making a technical mistake but why do you want to fail? Is it because you know that usage decisions of software are not based on technical merits? Or do you not want to be proved wrong? Or something else?
- nickysielicki 11y ago
  Let's go to an alternative universe where Hurd was successful in the 90's and it reached common usage to the extent that Linux has today. You're Western Digital in 2008 and you're making a TV set-top box called the WDTV-Live. I own one of these in real life universe. It runs linux, which is awesome, because that means that I can SSH into it. It runs an apache server in my home. It can download from usenet or torrents. I can control it via SSH instead of using the remote control.[0] In this alternative universe, WDLX going to use Hurd instead of linux, because for this small device it will certainly have better performance on their underpowered MIPS chip. And they're not going to ship anything besides what they have to, becasue this is a small embedded computer. What happens to that homebrew community when they ship a microkernel with proprietary servers for everything, and nothing else? It's going to be profoundly difficult to develop on this. You might already see this if you own a chromebook or a WDTV-- missing kernel modules means that you simply can't do anything without compiling your kernel. Couple this with secureboot and you're locked in. I'm no expert on these things, most of this is based on brief research from years ago. If you think that I'm wrong, please tell me why, I'd love to be proven wrong. But for the time being, I believe widespread implementations of microkernels would be very anti-general-purpose computing. [0]: http://wdlxtv.com/ http://wdlxtv.com/
  - vezzy-fnord 11y ago
    Your example doesn't make much sense because Hurd is the servers. The microkernel component itself is GNU Mach. Shipping an embedded appliance with a microkernel and proprietary servers again makes no sense, because it's akin to rewriting userspace from scratch on top of the base VMM, schedulers and disk I/O. Just for a TV set top?
  - minthd 11y ago
    But isn't basically always the tradeoff - if you want security ,you play by the rules of the company who built it ? is there even a theoretical way out of this ?
  - carussell 11y ago
    Where/how do the proprietary servers come in for a kernel that doesn't want to allow them (and therefore would go through no special effort to make them possible)? Remember that the reason you can link against glibc is because it's LGPL and not GPL. The LGPL was created for a reason. There's also a reason why when the decision was made to release Java under the GPL, Sun explicitly added a linking exception. It's because that isn't something you just automatically get for free.
  - isr 11y ago
    Isn't this dependent upon the microkernel's license? Wouldn't it be possible to use an open-source license which also explicitly forces servers which use it to also be covered under the same license? Something akin to to affero gpl?
  - caf 11y ago
    The idea of the Hurd is that any user is able to run whatever server they want - GNU has been concentrating on microkernels not because it's the new hotness but because they believe it's good architecture for more openness. So presumably in this hypothetical case you'd be able to upload and run whatever additional servers you needed on the WDTV. You might say "but they might make it impossible to login and do that", but they could have done the same under Linux just by not running sshd - however they didn't.
  - bitwize 11y ago
vezzy-fnord 11y ago
Microkernels have been running the world behind the scenes for a while now, but most people don't seem to have gotten the memo and are still stuck with associating the Mach server as representative of u-kernels in general.
- pjmlp 11y ago
  Yeah, for example each Symbian phone has one. Also Mach OS X and Windows are hybrid in design and not the monolithic traditional UNIX way.
- JoshTriplett 11y ago
  There have been wildly successful microkernels. One of Xen's greatest successes was demonstrating that to encourage widespread adoption of a microkernel, you rebrand it as a hypervisor. More recently, some people have started running software directly under Xen without a full OS, including language runtimes, all without ever calling it a microkernel.
  - cbd1984 11y ago
    Microkernels and hypervisors are not the same thing.
    - JoshTriplett 11y ago
      What's the difference between Xen and a microkernel? They both manage memory, do CPU scheduling, provide efficient message-passing, protect "processes" running underneath them from each other, and leave almost everything else to the "processes" running underneath them.
      - cbd1984 11y ago
        > What's the difference between Xen and a microkernel? Xen allows full OSes to be guests and run on top of it. Microkernels only allow servers to run on top of it, and those servers have to be purpose-written and cannot meaningfully be ported. Xen doesn't provide hardware abstraction and is fully invisible (except to the extent it advertises itself); microkernels are neither. Paravirtualization (what you did before VT-x and similar) was an oddity, and blurs these lines a tiny bit, but the distinction is fairly clear otherwise.
cbd1984 11y ago
Microkernels are the wave of the future and always will be.
- rodgerd 11y ago
  L4 is used in the secure element of every modern iPhone. OS X/XNU is based on microkernel designs. Windows is a hybrid.
  - bch 11y ago
    Are you asserting MacOS X is "based on microkernel designs" just because some versions[0] of Mach are a microkernel, or something else? [0] https://en.wikipedia.org/wiki/Mach_%28kernel%29 https://en.wikipedia.org/wiki/Mach_%28kernel%29
    - bch 11y ago
      Hrmmm. Digging deeper (and trawling my memory), I'm getting conflicting information: * https://en.wikipedia.org/wiki/XNU https://en.wikipedia.org/wiki/XNU * https://youtu.be/8RwlEZ88rKM https://youtu.be/8RwlEZ88rKM

PuercoPop 11y ago

I'm confused, I understand you think the Hurd is making a technical mistake but why do you want to fail? Is it because you know that usage decisions of software are not based on technical merits? Or do you not want to be proved wrong? Or something else?

nickysielicki 11y ago
Let's go to an alternative universe where Hurd was successful in the 90's and it reached common usage to the extent that Linux has today. You're Western Digital in 2008 and you're making a TV set-top box called the WDTV-Live. I own one of these in real life universe. It runs linux, which is awesome, because that means that I can SSH into it. It runs an apache server in my home. It can download from usenet or torrents. I can control it via SSH instead of using the remote control.[0] In this alternative universe, WDLX going to use Hurd instead of linux, because for this small device it will certainly have better performance on their underpowered MIPS chip. And they're not going to ship anything besides what they have to, becasue this is a small embedded computer. What happens to that homebrew community when they ship a microkernel with proprietary servers for everything, and nothing else? It's going to be profoundly difficult to develop on this. You might already see this if you own a chromebook or a WDTV-- missing kernel modules means that you simply can't do anything without compiling your kernel. Couple this with secureboot and you're locked in. I'm no expert on these things, most of this is based on brief research from years ago. If you think that I'm wrong, please tell me why, I'd love to be proven wrong. But for the time being, I believe widespread implementations of microkernels would be very anti-general-purpose computing. [0]: http://wdlxtv.com/ http://wdlxtv.com/
- vezzy-fnord 11y ago
  Your example doesn't make much sense because Hurd is the servers. The microkernel component itself is GNU Mach. Shipping an embedded appliance with a microkernel and proprietary servers again makes no sense, because it's akin to rewriting userspace from scratch on top of the base VMM, schedulers and disk I/O. Just for a TV set top?
- minthd 11y ago
  But isn't basically always the tradeoff - if you want security ,you play by the rules of the company who built it ? is there even a theoretical way out of this ?
- carussell 11y ago
  Where/how do the proprietary servers come in for a kernel that doesn't want to allow them (and therefore would go through no special effort to make them possible)? Remember that the reason you can link against glibc is because it's LGPL and not GPL. The LGPL was created for a reason. There's also a reason why when the decision was made to release Java under the GPL, Sun explicitly added a linking exception. It's because that isn't something you just automatically get for free.
- isr 11y ago
  Isn't this dependent upon the microkernel's license? Wouldn't it be possible to use an open-source license which also explicitly forces servers which use it to also be covered under the same license? Something akin to to affero gpl?
- caf 11y ago
  The idea of the Hurd is that any user is able to run whatever server they want - GNU has been concentrating on microkernels not because it's the new hotness but because they believe it's good architecture for more openness. So presumably in this hypothetical case you'd be able to upload and run whatever additional servers you needed on the WDTV. You might say "but they might make it impossible to login and do that", but they could have done the same under Linux just by not running sshd - however they didn't.
- bitwize 11y ago

vezzy-fnord 11y ago

Microkernels have been running the world behind the scenes for a while now, but most people don't seem to have gotten the memo and are still stuck with associating the Mach server as representative of u-kernels in general.

pjmlp 11y ago
Yeah, for example each Symbian phone has one. Also Mach OS X and Windows are hybrid in design and not the monolithic traditional UNIX way.
JoshTriplett 11y ago
There have been wildly successful microkernels. One of Xen's greatest successes was demonstrating that to encourage widespread adoption of a microkernel, you rebrand it as a hypervisor. More recently, some people have started running software directly under Xen without a full OS, including language runtimes, all without ever calling it a microkernel.
- cbd1984 11y ago
  Microkernels and hypervisors are not the same thing.
  - JoshTriplett 11y ago
    What's the difference between Xen and a microkernel? They both manage memory, do CPU scheduling, provide efficient message-passing, protect "processes" running underneath them from each other, and leave almost everything else to the "processes" running underneath them.
    - cbd1984 11y ago
      > What's the difference between Xen and a microkernel? Xen allows full OSes to be guests and run on top of it. Microkernels only allow servers to run on top of it, and those servers have to be purpose-written and cannot meaningfully be ported. Xen doesn't provide hardware abstraction and is fully invisible (except to the extent it advertises itself); microkernels are neither. Paravirtualization (what you did before VT-x and similar) was an oddity, and blurs these lines a tiny bit, but the distinction is fairly clear otherwise.

cbd1984 11y ago

Microkernels are the wave of the future and always will be.

rodgerd 11y ago
L4 is used in the secure element of every modern iPhone. OS X/XNU is based on microkernel designs. Windows is a hybrid.
- bch 11y ago
  Are you asserting MacOS X is "based on microkernel designs" just because some versions[0] of Mach are a microkernel, or something else? [0] https://en.wikipedia.org/wiki/Mach_%28kernel%29 https://en.wikipedia.org/wiki/Mach_%28kernel%29
  - bch 11y ago
    Hrmmm. Digging deeper (and trawling my memory), I'm getting conflicting information: * https://en.wikipedia.org/wiki/XNU https://en.wikipedia.org/wiki/XNU * https://youtu.be/8RwlEZ88rKM https://youtu.be/8RwlEZ88rKM