The OS2KRNL modules lies at the heart of OS/2 - it is essentially operating system.
The kernel comprises an number of internal components, each responsible for a different aspect of running the system. It also has a number of interfaces that provides services to applications, device drivers and file systems.
These aspects are now considered in a little more detail and are summarised in the diagram shown under: The OS/2 Kernel's Interfaces (steady state).