Improving Data Consistency in Mobile Computing Using Isolation-Only Transactions

Qi Lu and M. Satyanarayanan


Disconnected operation is an important technique for providing mobile access to shared data in distributed file systems. However, data inconsistency resulting from partitioned sharing remains a serious concern. This paper presents a new mechanism called isolation-only transaction(IOT) that uses serializability constraints to automatically detect read/write conflicts. The IOT consistency model provides a set of options for automatic and manual conflict resolution. In addition, application specific knowledge can be incorporated to detect and resolve conflicts. To preserve upward Unix compatibility, the IOT mechanism is provided as an optional file system facility and its flexible interfaces allow any existing Unix application to be executed as an IOT. This paper describes high level system design and implementation and concludes with related work and current status.