混合核心

混合核心（英语：Hybrid kernel），又译为混合式核心、混合内核，一种操作系统内核架构。传统上的操作系统内核可以分为宏内核（Monolithic kernel）与微核心（Micro kernel）两大基本架构，混合核心结合了这两种核心架构。

混合核心的基本设计理念，是以微核心架构来设计操作系统核心，但在实现上则采用宏内核的作法。混合核心实质上是微核心，只不过它让一些微核结构执行在用户空间的代码执行在核心空间，这样让核心的执行效率更高些。这是一种妥协做法，设计者参考了微核心结构的系统执行速度不佳的理论。

大多数现代操作系统遵循这种设计范畴，是用微核心的概念来设计，但是实现上则采用宏内核的作法，结合宏内核（Monolithic kernel）与微核心（Micro kernel）两种设计方法，形成第三种分类。但是这种分类法受到一些批评，如林纳斯·托瓦兹认为这种分类只是一种市场营销手法，因为它的架构实现方式接近于宏内核^[1]。

最有名的混合核心为Windows NT核心与XNU。

概论

这个设计方式是一种妥协下的设计。在设计理念上，采用微核心架构来设计，但因为微核心结构一直被批评为性能不佳，因此在实现上，则采用宏内核的作法。微核心架构将操作系统服务（task server）运行在用户空间，以保证系统的稳定可靠。与典型的微核心设计相较，在混合核心中，多数的操作系统服务（task server）仍然运行在核心空间中，与宏内核相同。因为让操作系统服务运行在核心空间，减少了消息传递及环境切换（content switch）带来的系统负担，这可以避免微核心架构常被批评的性能不佳问题；但也因此，这种设计无法提供微核心系统架构下的稳定性保证。

批评

林纳斯·托瓦兹认为，采用可加载核心模块不代表这个操作系统就是一种混合核心，如果模块跟内核使用同样的寻址空间，能够存取内核的资料结果，这种实现方式就是宏内核^[2]。以这种定义来看，混合核心实际上是宏内核的变种。

例子

NT内核

Windows NT、Windows 2000、Windows XP、Windows Server 2003以及Windows Vista和Windows 7等基于NT技术的微软视窗操作系统

XNU内核

macOS（前称Mac OS X及OS X，使用FreeBSD原始码和Mach内核来实现）
XNU（使用Mach内核）

其他

BeOS内核
DragonFly BSD
ReactOS内核

参见

注释

^ Linus Torvalds. [2018-06-13]. （原始内容存档于2021-01-09）. As to the whole "hybrid kernel" thing - it's just marketing. It's "Oh, those microkernels had good PR, how can we try to get good PR for our working kernel? Oh, I know, let's use a cool name and try to imply that it has all the PR advantages that that other system has.
^
The article goes to say that a hybrid kernel like NT's is not to be confused with a with monolithic kernels that can load modules like Linux. Again, this seems like nonsense to me - the stable driver ABI (and the closed source) has facilitated creating of many drivers outside of the NT kernel tree, but this is not a conceptual difference. The precise technique of loading a driver/module into the kernel doesn't really matter, if the driver shares the same address space and can have access to kernel structures.
——Linus Torvalds，http://www.realworldtech.com/forums/index.cfm?action=detail&id=66630&threadid=66595&roomid=11

[1] Linus Torvalds. [2018-06-13]. （原始内容存档于2021-01-09）. As to the whole "hybrid kernel" thing - it's just marketing. It's "Oh, those microkernels had good PR, how can we try to get good PR for our working kernel? Oh, I know, let's use a cool name and try to imply that it has all the PR advantages that that other system has.

[2] 
The article goes to say that a hybrid kernel like NT's is not to be confused with a with monolithic kernels that can load modules like Linux. Again, this seems like nonsense to me - the stable driver ABI (and the closed source) has facilitated creating of many drivers outside of the NT kernel tree, but this is not a conceptual difference. The precise technique of loading a driver/module into the kernel doesn't really matter, if the driver shares the same address space and can have access to kernel structures.
——Linus Torvalds，http://www.realworldtech.com/forums/index.cfm?action=detail&id=66630&threadid=66595&roomid=11

[1]

[2]