Differences between User Mode and Kernel mode -
The difference between user and kernel modes are as follows:
1. Processes in user mode can access their own instructions and data but not kernel instructions and data. How ever, processes in kernel mode can access kernel and user addresses. For example, The virtual address space of a process may be divided between addresses that are accessible only in kernel mode and address that are accessible in either mode.
2. A process in user mode does not have the capability to execute all the machine instructions. Some machine instructions are given special advantage and result in an error when executed in user mode. While kernel has no such limitation, it can execute all machine instructions.