Difference Between User Mode And Kernel Mode – Learn Loner

User Mode	Kernel Mode
User mode is the mode in which user-level applications and processes run.	Kernel mode is the mode in which the OS kernel runs.
In user mode, programs can only access a limited set of resources defined by the OS.	In kernel mode, the kernel has access to all the resources of the system, including privileged resources.
User mode is considered a non-privileged mode of operation because it has limited access to system resources.	Kernel mode is considered a privileged mode of operation because it has access to all system resources.
Programs running in user mode cannot execute privileged instructions or access privileged memory addresses.	In kernel mode, the kernel can execute privileged instructions and access privileged memory addresses.
User mode programs cannot modify system resources or interfere with other programs without going through the OS.	Kernel mode programs have full control over the system and can modify system resources and interfere with other programs.
User mode programs cannot modify the behavior of the OS or install new device drivers or system services.	Kernel mode programs can modify the behavior of the OS, install new device drivers or system services.
User mode programs can be terminated by the OS if they attempt to perform an illegal operation or consume too many resources.	The kernel cannot be terminated by user mode programs.
User mode programs rely on the OS for accessing system resources and performing privileged operations.	The kernel provides the services and functions required by user mode programs.
User mode programs run in a protected environment provided by the OS, which prevents them from crashing the entire system.	Kernel mode programs have direct access to system resources, which makes them more powerful but also more dangerous.
User mode is the default mode of operation for most programs in an OS.	Kernel mode is reserved for the OS kernel and critical system services.

Kernel mode and User mode by Learn Loner

User Mode	Kernel Mode
Limited access to system resources and hardware	Full access to system resources and hardware
Runs applications and programs that are not part of the operating system	Runs the core of the operating system, including device drivers and the scheduler
Programs cannot execute privileged instructions or access kernel memory directly	Programs can execute privileged instructions and access kernel memory directly
Less secure as programs can only access their own memory space	More secure as programs are prevented from accessing memory space that belongs to other programs
Programs are isolated from other programs, providing protection against crashes and errors	Programs can communicate and share memory with other programs, allowing for efficient data transfer
Lower-level programming languages like Assembly cannot be used in this mode	Lower-level programming languages like Assembly can be used in this mode
System calls must be used to access kernel resources and services	No need for system calls to access kernel resources and services
Interrupts are handled by the operating system	Interrupts can be handled by device drivers in the kernel
Generally faster and more efficient than kernel mode	Generally slower and less efficient than user mode
Cannot modify kernel data or code	Can modify kernel data or code

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