Can you explain the difference between kernel space and user space in an operating system?

In operating systems, kernel space and user space are two different privilege levels and memory regions.

• Kernel space is where the OS kernel code executes. It has full access to hardware resources, memory, and devices. Code in kernel space operates with high privileges and is responsible for managing processes, memory, drivers, etc.

• User space is where user applications run. Programs here operate with limited rights to prevent accidental or malicious damage to the system.

Differences:

• Security: User processes are isolated from each other and from the kernel.
• Resource access: To interact with hardware, applications make system calls, transitioning into kernel space.
• Stability: A failure in user space usually does not cause the entire system to crash, whereas a failure in the kernel is critical.

For example, when you open a file in a program, it makes a system call that switches execution to kernel space to access the file system.