5 ms·

The NT kernel is surprisingly small and well-factored to begin with - it is a lot closer to a 'pure' philosophy (e.g. Microkernel) than something like Linux to

by nxc18 9y ago

The NT kernel is surprisingly small and well-factored to begin with - it is a lot closer to a 'pure' philosophy (e.g. Microkernel) than something like Linux to begin with. If you have a problem with Windows being overcomplicated or in need of refactor it is almost certainly something to do with not-the-kernel. If you look at something like the Linux kernel its actually much larger than Windows. It needs to have every device driver known to man (except that one WiFi/GPU/Ethernet/Bluetooth driver you need) because internally the architecture is not cleanly defined and kernel changes also involve fixing all the broken drivers.

GlobalServices 9y ago
Yes! Windows Kernel is a much more "modern" microkernel architecture than any of the circa-1969 Unix-like architectures popular today. We use Windows 10 / Windows Serve for everything at our company, and we have millions of simultaneously connected users on single boxes. No problems and easy to manage.
andrey_utkin 9y ago
Could you please share a link to NT kernel sources so that I take a look? It is not true that internal architecture of Linux drivers is not clearly defined. It is just a practical approach to maintenance of drivers (as an author of one Linux hardware driver I'm pretty sure the best possible). Reasoning is outlined in famous "Stable API nonsense" document http://elixir.free-electrons.com/linux/latest/source/Documentation/process/stable-api-nonsense.rst http://elixir.free-electrons.com/linux/latest/source/Documen... I don't think Windows approach is worth praising here. It results in a lot of drivers stopping working after few major Windows release upgrades. In Linux, available drivers can be maintained forever.
- nxc18 9y ago
  If you are sufficiently motivated, NT 4 leaked many years ago and you could find it; it even has interesting things like DEC Alpha support & various subsystems still included IIRC. Perhaps you could find a newer version like 5.2 on GitHub or another site, but beware, as a Linux dev/contributor, you probably don't want to have access to that. FWIW, I've stumbled upon both of those things in my personal research while I had legitimate access to the 5.2 sources as a student. It turns out Bing will link you directly to the Windows source code if you search for <arcane MASM directive here>. Yes, I'm in the process of reporting this to Microsoft and cleansing myself of that poison apple.
caf 9y ago
Small and well-factored the core kernel may be, but if you're parsing fonts in kernel mode, you ain't a microkernel. ( https://googleprojectzero.blogspot.com.au/2015/07/one-font-vulnerability-to-rule-them-all.html https://googleprojectzero.blogspot.com.au/2015/07/one-font-v... )
- nxc18 9y ago
  For sure, and Windows is not a microkernel, but it does have separated kernel-in-kernel and executive layers; it would approach being a microkernel architecture if the executive was moved into userland. This is similar to how macOS would be a microkernel, if everything wasn't run in kernel mode (mach, on which it is partially based, is a microkernel). Of course the issue here is that after NT 4, GDI has been in kernel mode; this is necessary for performance reasons. Prior to that it was a part of the user mode Windows subsystem. I'd be curious to see if GDI moved back to userland would be acceptable with modern hardware, but I suspect MS is not interested in that level of churn for minimal gain.

by nxc18 9y ago

GlobalServices 9y ago

Yes! Windows Kernel is a much more "modern" microkernel architecture than any of the circa-1969 Unix-like architectures popular today. We use Windows 10 / Windows Serve for everything at our company, and we have millions of simultaneously connected users on single boxes. No problems and easy to manage.

andrey_utkin 9y ago

Could you please share a link to NT kernel sources so that I take a look? It is not true that internal architecture of Linux drivers is not clearly defined. It is just a practical approach to maintenance of drivers (as an author of one Linux hardware driver I'm pretty sure the best possible). Reasoning is outlined in famous "Stable API nonsense" document http://elixir.free-electrons.com/linux/latest/source/Documentation/process/stable-api-nonsense.rst http://elixir.free-electrons.com/linux/latest/source/Documen... I don't think Windows approach is worth praising here. It results in a lot of drivers stopping working after few major Windows release upgrades. In Linux, available drivers can be maintained forever.

nxc18 9y ago
If you are sufficiently motivated, NT 4 leaked many years ago and you could find it; it even has interesting things like DEC Alpha support & various subsystems still included IIRC. Perhaps you could find a newer version like 5.2 on GitHub or another site, but beware, as a Linux dev/contributor, you probably don't want to have access to that. FWIW, I've stumbled upon both of those things in my personal research while I had legitimate access to the 5.2 sources as a student. It turns out Bing will link you directly to the Windows source code if you search for <arcane MASM directive here>. Yes, I'm in the process of reporting this to Microsoft and cleansing myself of that poison apple.

caf 9y ago

Small and well-factored the core kernel may be, but if you're parsing fonts in kernel mode, you ain't a microkernel. ( https://googleprojectzero.blogspot.com.au/2015/07/one-font-vulnerability-to-rule-them-all.html https://googleprojectzero.blogspot.com.au/2015/07/one-font-v... )

nxc18 9y ago
For sure, and Windows is not a microkernel, but it does have separated kernel-in-kernel and executive layers; it would approach being a microkernel architecture if the executive was moved into userland. This is similar to how macOS would be a microkernel, if everything wasn't run in kernel mode (mach, on which it is partially based, is a microkernel). Of course the issue here is that after NT 4, GDI has been in kernel mode; this is necessary for performance reasons. Prior to that it was a part of the user mode Windows subsystem. I'd be curious to see if GDI moved back to userland would be acceptable with modern hardware, but I suspect MS is not interested in that level of churn for minimal gain.