Dhara: A Service Abstraction-Based OS Kernel Design Model

Traditional procedural operating system (OS) kernels sacrifice maintainability and understandability for optimum performance. Though object oriented (OO) kernels can address these problems up to a certain extent, they lack the layered approach of services and service compositions. We present a new kernel design model Dhara, that raises the level of abstraction from objects and procedures to services. The service model of Dhara is richer in abstractions than current web service model and paves the way for building a new distributed OS kernel. Dhara conceives an OS as being constructed by multiple stacks of services containing several layers of abstracted services. A key research challenge we envisage in building such model is automatic service compositions of kernel services which can provide desired QoS. A kernel built using Dhara can easily be customized using composed services to derive optimal performance for different applications such as databases. A prototype is developed using Linux kernel as a case study by applying the design concepts of Dhara. We show that overhead of implementation of Dhara is 5% to 15%, which is reasonable, considering the advantages of new design and increased capacity of the hardware in recent times.