4 ms·

I haven't profiled our Windows kernel driver across different kernel versions (maybe I should!) but I'd like to offer this perspective: the kernel is incredibly

by greenn 3y ago

I haven't profiled our Windows kernel driver across different kernel versions (maybe I should!) but I'd like to offer this perspective: the kernel is incredibly stable from my driver development point of view. The biggest reason we ship different drivers for Windows 7/8/10 is just that newer WDKs don't support anything older than 10. The kernel has remained remarkably consistent while still offering new features we can take advantage of on non-legacy systems.

fulladder 3y ago
I think the reason you're finding it to be so stable is because nothing in that kernel has changed since Windows XP.
- greenn 3y ago
  A fair amount has been changed or added, I'd say. I recommend the Windows Internals book if you're interested in learning about the Windows kernel. The 7th edition just came out.
  - fulladder 3y ago
    That's fair. My comment is not well-informed with regard to whatever has happened in the last 10 years. The impression I formed back in the late-2000s and early 2010s when I was doing this type of development was that there was very little change in the low-level NT kernel. I actually don't think this is a bad thing; going from XP to Vista was a breeze because nothing about the driver APIs changed in the slightest, and Microsoft even provided a bunch of new filesystem examples with the Vista DDK.
    - greenn 3y ago
      Oh you're totally right about the driver APIs. A fair amount has been added, but that stuff gets a new export to avoid breaking anything. For example, there's a dozen different `ExAllocate`s now. I wouldn't call myself a driver-writing expert but I'm sure that same driver for Vista could be made to target Windows 10 with little effort.
- FirmwareBurner 3y ago
  That's just plain wrong.
RedShift1 3y ago
I don't know why "incredibly stable" is such a remarkable thing, the whole point of an operating system and a kernel is to offer a stable API to write your applications against.
- greenn 3y ago
  I'm talking about the kernel space itself, not the APIs exposed to userland to interface with the kernel from your application. Internal APIs and behaviors are mostly identical over the past ~20 years, and any changes are usually moved to a new export. I don't think this should be taken for granted.
- FirmwareBurner 3y ago
  >I don't know why "incredibly stable" is such a remarkable thing It's remarkable when you look at the landscape of Linux and Mac device drivers. Can you run non-kernel drivers for Linux 2.6 on 6.6? Can you install a device driver from 2007 on a modern MacOS? Well, many Windows 7 drivers also work on 11. That's stability.
  - RedShift1 3y ago
    That's kind of the point I'm trying to make here, an operating system and kernel is supposed to provide you with something stable to build on. It's its raison d'être. Should the stability of a bridge be considered remarkable? No, it's an entire engineering discipline to making stable bridges, because an unstable bridge is useless. The same goes for an operating system and kernel.
    - tentacleuno 3y ago
      > Should the stability of a bridge be considered remarkable? From a purely engineering perspective, most certainly.
    - FirmwareBurner 3y ago
      If it isn't so remarkable why doesn't every OS do it?

by greenn 3y ago

fulladder 3y ago

I think the reason you're finding it to be so stable is because nothing in that kernel has changed since Windows XP.

greenn 3y ago
A fair amount has been changed or added, I'd say. I recommend the Windows Internals book if you're interested in learning about the Windows kernel. The 7th edition just came out.
- fulladder 3y ago
  That's fair. My comment is not well-informed with regard to whatever has happened in the last 10 years. The impression I formed back in the late-2000s and early 2010s when I was doing this type of development was that there was very little change in the low-level NT kernel. I actually don't think this is a bad thing; going from XP to Vista was a breeze because nothing about the driver APIs changed in the slightest, and Microsoft even provided a bunch of new filesystem examples with the Vista DDK.
  - greenn 3y ago
    Oh you're totally right about the driver APIs. A fair amount has been added, but that stuff gets a new export to avoid breaking anything. For example, there's a dozen different `ExAllocate`s now. I wouldn't call myself a driver-writing expert but I'm sure that same driver for Vista could be made to target Windows 10 with little effort.
FirmwareBurner 3y ago
That's just plain wrong.

RedShift1 3y ago

I don't know why "incredibly stable" is such a remarkable thing, the whole point of an operating system and a kernel is to offer a stable API to write your applications against.

greenn 3y ago
I'm talking about the kernel space itself, not the APIs exposed to userland to interface with the kernel from your application. Internal APIs and behaviors are mostly identical over the past ~20 years, and any changes are usually moved to a new export. I don't think this should be taken for granted.
FirmwareBurner 3y ago
>I don't know why "incredibly stable" is such a remarkable thing It's remarkable when you look at the landscape of Linux and Mac device drivers. Can you run non-kernel drivers for Linux 2.6 on 6.6? Can you install a device driver from 2007 on a modern MacOS? Well, many Windows 7 drivers also work on 11. That's stability.
- RedShift1 3y ago
  That's kind of the point I'm trying to make here, an operating system and kernel is supposed to provide you with something stable to build on. It's its raison d'être. Should the stability of a bridge be considered remarkable? No, it's an entire engineering discipline to making stable bridges, because an unstable bridge is useless. The same goes for an operating system and kernel.
  - tentacleuno 3y ago
    > Should the stability of a bridge be considered remarkable? From a purely engineering perspective, most certainly.
  - FirmwareBurner 3y ago
    If it isn't so remarkable why doesn't every OS do it?