The importance of modifiability of complete operating system as design factor for operating system development is ever increasing. Modifiability can be achieved by modular structure, since total system can be described easily and clearly by using modular structure.
Real time system requires minimum system overhead. System overhead can be reduced by minimizing the number of processes and switches between system modules. But in order to upgrade modifiability, performance of system must be tolerated.
This thesis describes modular structure of system functions devided into dynamic structure and static structure. Dynamic structure consists of system functions which support user tasks and static structure consists of system functions which support dynamic structure, such as processor management, I/O management and file management. System designed is implemented on NOVA 840 with teletype and moving head disk.
