Answer - Kernels are basically of two types: a. Monolithic Kernels - In this architecture of kernel, all the system services were packaged into a single system module which lead to poor maintainability and huge size of kernel. b. Microkernels - They follow the modular approach of architecture. Maintainability became easier with this model as only the concerned module is to be altered and loaded for every function. This model also keeps a tab on the ever growing code size of the kernel.