Cooperative Data Management and its Application to Mobile Computing

Abstract

Mobile computing and workgroup computing are emerging technologies which have so far been treated independently. Current approaches to support cooperative work neglect the special characteristics of mobile environments like limited bandwidth or temporary disconnection. On the other hand, approaches to support disconnected operation rely on the assumption that the degree of data-sharing is low which is obviously not appropriate for cooperative work. In this paper, we utilize the COACT cooperative transaction model to provide support for parallel activities in mobile environments. We present a system architecture that is able to cope with the special characteristics of mobile environments and a formal framework for the consistent information exchange between mobile users. The paper shows how the COACT history merge algorithm reduces conflicts by exploiting operation semantics and offering consistent sequences of operations. We believe that our new approach is a viable solution to the growing demand for cooperation in mobile environments.

Transactional Support for Cooperative Applications

“…Execution order rules have to be enforced for each private workspace and the common workspace separately [RKT + 95a, KTW + 96d, FEdB96]. This allows the enforcement of execution order rules even for those applications, where the workspaces are not permanently connected, e.g., in mobile environments [KTW97b,KTW97a]. For more details on execution order rules, see [FEdB96,FEdBA97,FEdB98, KTW + 96d].…”

“…In this chapter, we show how the COACT model can be utilized to support cooperation among users in mobile computing systems [KTW97a,KTW97b,KTW97c,Wäs96]. We extend CO-ACT' s system architecture (cf.…”

“…Especially asynchronous cooperative applications are suitable for being used in mobile environments [KTW97a,KTW97b]. This kind of applications already have to deal with part-time disconnection, one of the central issue in mobile computing.…”

“…In the following, we extend our work on COACT to support disconnected operation mode in mobile environments [KTW97a,KTW97b]. To enable cooperation among mobile users and among stationary and mobile users, we instantiate the COACT system architecture (cf.…”

“…However, for different application domains like mobile environments, which are outside the scope of the prototype implementation, other realizations are more appropriate. For example, local storage of workspace histories would increase the independence of the central storage system [KTW97b,KTW97a]. In the implementation of the cooperative calendar manager [Kar98] based on the COACT model the histories are stored locally at each workspace.…”