The diagram in **Fig 1.
8: Microkernel** illustrates the architecture of a
microkernel-based operating system. It highlights the separation of core
kernel functions and user-space services.
### **Key Points from the Diagram:**
1. **Separation of User and Kernel Mode:**
- The microkernel architecture moves most OS services (like memory
management, process management, and file systems) into **user space**
instead of keeping them in the kernel.
- Only essential functions (like inter-process communication and hardware
communication) remain in the **kernel mode** for security and stability.
2. **Message Passing for Communication:**
- Unlike monolithic kernels where modules interact directly, microkernels
use **message passing** to exchange information between modules (e.g.,
memory module, process module, file module).
- This reduces the risk of system crashes because each module runs
independently in user mode.
3. **OS Interface and System Calls:**
- The **OS interface** at the top allows user applications to interact with
the system.
- **System calls** are used to request services from the microkernel, which
then communicates with the appropriate module in user space.
### **Benefits of this Design (as shown in the diagram):**
- **Modular & Extensible:** Easier to modify or add new OS components
without affecting the kernel.
- **More Secure:** Limited kernel functions reduce the risk of crashes and
vulnerabilities.
- **More Reliable:** Faults in user-space services (like file management) do
not crash the entire system.
This diagram visually explains how a **microkernel OS isolates critical kernel
functions while shifting non-essential services to user space** to improve
security and stability.
