The MARUTI operating system is designed to support real-time applications on a variety of hardware systems. The kernel supports objects as primitive entities, and provides a communication mechanism that allows transparent distribution in networked systems. Fault tolerance is provided through replication and consistency-control mechanisms. Most importantly, MARUTI supports guaranteed-service scheduling, in which jobs that are accepted by the system are verified to satisfy general time constraints.Guaranteed-service scheduling means that, given a job with a set of service requirements and time constraints, the system automatically verifies the schedulability of each component of the job with respect to the job's constraints and those of other jobs in the system. These time constraints include those that govern interrupt processing, which allows the MARUTI approach to succeed where tess rigorous approaches do not. The result is that MARUTI applications can be executed in a predictable, deterministic fashion.

Allocation of resources in ''next-generation" real-time operating systems requires some important features in addition to those demonstrated by current systems, resulting in an increased complexity of each system. The allocation is closely related to the scheduling, and the two are based on time considerations, rather then on a static priority scheme. The allocation is fault tolerance motivated, to cope with the application's reliability goals. Distributed system issues and adaptive behavior requirements increase the complexity and significance of the allocation approach.The allocation scheme we propose here accomplishes the hard real-time goal of guaranteeing a deadline satisfaction in case the job is accepted. In addition, this allocation scheme supports fault tolerance objectives in both damage containment and resiliency requirements. It does this in cooperation with a schedulability verification mechanism, and with an object architecture in which for each object there exists a calendar that maintains the time of its execution. A nice feature of this scheme is the way in which it can be used for reallocation while increasing the resiliency.

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