LIMOS: A Tiny Real-Time Micro-Kernel for Wireless Objects

TinyOS is a natural event-driven single-task system. It fits for the single-task specific-application but not for the real-time multi-task application; while, SDREAM is a typical distributed real-time micro-kernel. It supports real-time multi-task applications but normally consumes more resources. This paper presents a novel hybrid real-time micro-kernel: LIMOS (lightweight multi-threading operating system), which combines the features of TinyOS and SDREAM. LIMOS adopts the event & thread two-level architecture and correspondingly has a two-level scheduling policy: ´event-driven´ (high level scheduling for events) and ´priority-based preemptive´ (low level scheduling for threads). LIMOS adopts the LINDA concept: tuple space and in & out primitive-pair for system synchronization & communication. At present, LIMOS has been applied into a wireless application with the integration of multi-wireless techniques (RFID, ZigBee, and WiFi)