Error Detection and Recovery Issues in Real-Time Computer Systems

本课题对回滚恢复技术的硬件问题--错误检测和恢复进行了研究。本研究的主要目的是(1)设计一种并发错误检测方案，以促进多任务和多处理器系统中的恢复；(2)开发一种恢复数据保护方案，并研究其对回滚策略的影响。具有低错误延迟的错误检测对于实时系统中的成功恢复至关重要。然而，在大多数系统中，检测错误的硬件是包含在内的。看门狗处理器用于检测错误并启动恢复。控制流检查技术用于错误的在线检测。为了获得可控的错误延迟，使用圈复杂度的概念。为了在回滚时保护恢复数据，使用了恢复缓存。提出了一种新的回滚模型，将恢复缓存用于恢复数据保护。通过建立优化模型，研究了缓存对回滚的影响。将通过实际程序进行分析和实验研究，以验证模型和回滚所用的方法。

In this project, the hardware issues - error detection and recovery - of rollback recovery technique are studied. The main objectives of this research are (1) to design a concurrent error detection scheme to facilitate recovery in multitasking and multiprocessor systems, and (2) to develop a scheme for recovery data protection and study its impact on the rollback strategy. Detection of errors with low error latency is vital for successful recovery in real-time systems. In most systems, however, the hardware to detect errors is subsumed. A watchdog processor is used to detect errors and initiate recovery. The technique of control flow checking is used for the on-line detection of errors. The concept of cyclomatic complexity is used in order to obtain a controllable error latency. In order to protect the recovery data in rollback, a recovery cache is employed. A new model for rollback is formulated to take into effect the use of a recovery cache for recovery data protection. The impact of the cache on rollback is investigated by deriving an optimization model. Analysis and experimental studies with real programs will be conducted to validate the model and the methods used for rollback.