The maturity of schedulabilty analysis techniquesfor fired-prioritypreemptive scheduling has enabled the consideration of timing issues at design time using a specification of the tasking architecture and estimates of execution timesfor tasks. While successful, this approach has limitations since the preemptive multi-tasking model does not scale wellfor a large number of tasks, and the fired priority scheduling theory does not work well with many object-oriented design methods. In this paper we present an approach that scales well even when the design consists of a large number of concurrentjobs. The approach avoids any unnecessary preemptability in the system, thereby resulting in reduced run-time overheads frompreemptions and associated context-switches.It also allows significant memory savings by groupingjobs into non-preemptivegroups and then sharing the stack space between them. Our approach is based on our earlier work on scheduling using preemption thresholds that allowsparamet...