Definition of monolithic operating system
The monolithic operating system is a very basic operating system in which file management, memory management, device management, and process management is directly controlled within the kernel. All these components like file management, memory management etc. are located within the kernel.
History of monolithic operating system
The monolithic operating system is also known as the monolithic kernel. This is an old type of operating system. They were used to perform small tasks like batch processing, time sharing tasks in banks. Monolithic kernel acts as a virtual machine which controls all hardware parts. It is different than microkernel which has limited tasks. A microkernel is divided into two parts i.e. kernel space and user space. Both these parts communicate with each other through IPC (Inter-process communication). Microkernel advantage is that if one server fails then other server takes control of it. Operating systems which use monolithic architecture were first time used in the 1970’s.
Features of the monolithic operating system
Simple structure:
This type of operating system has a simple structure. All the components needed for processing are embedded into the kernel.
Works for smaller tasks:
It works better for performing smaller tasks as it can handle limited resources.
Communication between components:
All the components can directly communicate with each other and also with the kernel.
Fast operating system:
The code to make monolithic kernel is very fast and robust.
Limitations of a monolithic operating system
- Code written in this operating system (OS) is difficult to port.
- Monolithic OS has more tendency to generate errors and bugs. The reason is that user processes use same address locations as the kernel.
- Adding and removing features from monolithic OS is very difficult. All the code needs to be rewritten and recompiled to add or remove any feature.
Examples of monolithic operating system
- VMS
- Linux
- OS/360
- OpenVMS
- Multics
- AIX
- BSD
