Long description

The figure consists of 5 layers. The first layer is labeled Users and the second layer is labeled Standard utility programs (shell, editors, compilers, etc.). A downward arrow is pointed toward the second layer and is labeled User interface. The third layer is labeled Standard library (open, close, read, write, fork, etc.) and a downward arrow is pointed toward the third layer labeled Library interface. The fourth layer is labeled Linux operating system (process management, memory management, the file system, I slash O, etc.) and a downward arrow is pointed toward the third layer is labeled System call interface. The fifth layer is labeled Hardware (CPU, memory, disks, terminals, etc.). The second and third layer is marked User mode and the third layer is marked Kernel mode.