Now we understand that one can invoke kernel services by issuing a system call. When this occurs, the calling process runs the kernel code of the system call in kernel mode. This is termed process context – kernel code is now running in the context of the process that invoked the system call.

Process context code has the following attributes:

• Always triggered by a process (or thread) issuing a system call
• Top-down approach
• Synchronous execution of kernel code by a process