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One of those things is not like the others. BeOS did not have a microkernel.

by zokula 8y ago

nickpsecurity 8y ago
All the reporting I've seen on it said it had a microkernel. I've included both the first thing from Google and my UNIX Alternatives List that has an in-depth link on BeOS. https://arstechnica.com/information-technology/2008/02/first-look-haiku-poetically-resurrects-beos/ https://arstechnica.com/information-technology/2008/02/first... https://news.ycombinator.com/item?id=10957020 https://news.ycombinator.com/item?id=10957020 It also had the kind of compile-time slowdowns one expects with a lot of context switches on older CPU's. So, what's your source that there's not a microkernel at the center?
- waddlesplash 8y ago
  BeOS absolutely did not have a microkernel; all the hardware drivers, filesystem interfaces, and lowest-level network protocols ran in ring 0.
  - nickpsecurity 8y ago
    I appreciate you replying. Since it's you saying it, I'll stop saying it's a microkernel for now. I am curious why people said it so much. Maybe you could help there in even there was a sensible reason for the misinformation. Did it have nothing of the sort? A microkernel-like component in center of monolith like NT? Microkernel architecture with key stuff in kernel mode for performance like hybrids do? Did you see anything fitting the term in any BeOS release? And how would you classify its architecture?
    - waddlesplash 8y ago
      I'd classify the BeOS kernel as a modular-ish monolithic kernel. I'm a bit fuzzy on some of the more precise details, like the network stack (which they rewrote 3 or 4 times...) but I know that all drivers, at least, ran in ring 0. Haiku's kernel is also monolithic, although we have a few hybrid tendencies (FUSE, but it's not widely used) and even more modularity than BeOS had, but we are still mostly source-compatible with the BeOS kernel. I don't know why people say it's a microkernel; people say the same of Haiku, but it's just not the case. Perhaps it's because the dynamic kernel module system is built-in and virtually all kernel modules are stored as shared objects and loaded on startup, vs. Linux's more static approach, at least historically? That's not at all what's meant by the term "monolithic", but popular perception is often wrong...
      - nickpsecurity 8y ago
        Alright, that makes sense. I even suspected key drivers were in kernel mode given the performance on its kind of hardware. They might be saying it just because they don't know what a microkernel is. It might also be some new usage based on smaller, more-efficient kernels like used in containers. Who knows.

One of those things is not like the others. BeOS did not have a microkernel.

by zokula 8y ago

One of those things is not like the others. BeOS did not have a microkernel.

All the reporting I've seen on it said it had a microkernel. I've included both the first thing from Google and my UNIX Alternatives List that has an in-depth link on BeOS. https://arstechnica.com/information-technology/2008/02/first-look-haiku-poetically-resurrects-beos/ https://arstechnica.com/information-technology/2008/02/first... https://news.ycombinator.com/item?id=10957020 https://news.ycombinator.com/item?id=10957020 It also had the kind of compile-time slowdowns one expects with a lot of context switches on older CPU's. So, what's your source that there's not a microkernel at the center?

waddlesplash 8y ago
BeOS absolutely did not have a microkernel; all the hardware drivers, filesystem interfaces, and lowest-level network protocols ran in ring 0.
- nickpsecurity 8y ago
  I appreciate you replying. Since it's you saying it, I'll stop saying it's a microkernel for now. I am curious why people said it so much. Maybe you could help there in even there was a sensible reason for the misinformation. Did it have nothing of the sort? A microkernel-like component in center of monolith like NT? Microkernel architecture with key stuff in kernel mode for performance like hybrids do? Did you see anything fitting the term in any BeOS release? And how would you classify its architecture?
  - waddlesplash 8y ago
    I'd classify the BeOS kernel as a modular-ish monolithic kernel. I'm a bit fuzzy on some of the more precise details, like the network stack (which they rewrote 3 or 4 times...) but I know that all drivers, at least, ran in ring 0. Haiku's kernel is also monolithic, although we have a few hybrid tendencies (FUSE, but it's not widely used) and even more modularity than BeOS had, but we are still mostly source-compatible with the BeOS kernel. I don't know why people say it's a microkernel; people say the same of Haiku, but it's just not the case. Perhaps it's because the dynamic kernel module system is built-in and virtually all kernel modules are stored as shared objects and loaded on startup, vs. Linux's more static approach, at least historically? That's not at all what's meant by the term "monolithic", but popular perception is often wrong...
    - nickpsecurity 8y ago
      Alright, that makes sense. I even suspected key drivers were in kernel mode given the performance on its kind of hardware. They might be saying it just because they don't know what a microkernel is. It might also be some new usage based on smaller, more-efficient kernels like used in containers. Who knows.