A pattern language for porting micro-kernels

Abstract

Macro-kernels are dificult t o port to a new hardware platform. Durang the znztzal phases of a port, much tame and effort as lost o n debugging critical machine-dependent subsystems. These subsystems are generally very tzghtly coupled and cannot be tested zn a n zncremental fashaon.Tzght coupling occurs because the subsystems share m a n y global varzables forczng them to be debugged wzth the complete macro-kernel's code. T h e problem of organizing and documenting new mzcro-kernel ports has so f a r receaved lattle attentaon, and the work descrabed zn thas paper as a n attempt to fill thas gap. This paper describes a set of patterns (pattern language) whzch captures the design decasions of the anztaal porting procedure of mzcro-kernels for embedded systems zn a systematac and ancremental fashaon. T h e problem, context, and solutzon behznd major desagn patterns as presented along wath a n outlane of thew consequences, constraants and applacabzlzty to the port. In the course of several zterataons, thzs pattern language has been refined through thezr use zn portzng of exasttng embedded macrokernels to dzfferent hardware platforms.