Monolithic kernel
From Free net encyclopedia
Image:Kernel-monolithic.png A monolithic kernel defines a high-level virtual interface over the hardware, with a set of primitives or system calls to implement operating system services such as process management, concurrency, and memory management in several modules that run in supervisor mode.
Even if every module servicing these operations is separate from the whole, the code integration is very tight and difficult to do correctly, and, since all the modules run in the same address space, a bug in one module can bring down the whole system. However, when the implementation is complete and trustworthy, the tight internal integration of components allows the low-level features of the underlying system to be effectively utilized, making a good monolithic kernel highly efficient. In a monolithic kernel, all the processes such as the filesystem management run in an area called the kernel mode.
More modern monolithic kernels such as Linux, FreeBSD and Solaris can load executable modules at runtime, allowing easy extension of the kernel's capabilities as required, while helping to keep the amount of code running in kernelspace to a minimum. Nevertheless, this feature must not be confused with the hybrid kernel architecture.
Monolithic kernel examples
- Traditional Unix kernels, such as the kernels of the BSDs and Solaris
- Linux kernel
- Some educational kernels, such as Agnix
- MS-DOS, Microsoft Windows 9x series (Windows 95, Windows 98 and Windows 98SE) and Windows Me.