Software Rejuvenation in Embedded Systems

Mobile communication devices have multitasking embedded software running in their operating systems (OS) as well as applications. Both the OS modules and the application components are assigned predetermined memory in those devices due to near-realtime performance requirements and lack of virtual memory. Memory (stack and heap) overflow problems occur in such software components because of programmer's inability to accurately estimate the size of the needed memory and also because of Mandelbugs due to their complexity. A new software rejuvenation variation called Opportunistic Micro Rejuvenation (OMR) is proposed where a task that "misbehaves" is identified and rejuvenated at an opportune instant. Following the traditional model for software rejuvenation, a Stochastic Area Network model is used to simulate and study the availability of such embedded systems with OMR. It is shown that OMR alone will increase the availability only slightly but when combined with other memory management techniques, such as shared supplementary memory, OMR wilt increase the availability significantly.