Traditional locking mechanism is fit for the concurrency controlling and data consistency maintenance undercentralized architecture, but its response is slow, so it can not be used as concurrency controlling strategy ...Traditional locking mechanism is fit for the concurrency controlling and data consistency maintenance undercentralized architecture, but its response is slow, so it can not be used as concurrency controlling strategy for real-time distributed cooperative editing system. Moreover, operation transformation and data consistency maintenancetechnology are able to assure of quick response and unconstraint, but can't solve the context-specific inconsistencyproblems. Enlightened by the idea of operation transformation and optimistic locking mechanism, we bring forwardthe concurrency control algorithm of optimistic locking based on relative position. In this algorithm, the start positionof locking region and the position of operation are relative, and they are not transformed into absolute position untiloperations are sent to cooperative sites. Furthermore, any coeditor can edit in advance before his/her locking is con-firmed. If his/her locking is successful, the previous operations go into effect, or else undo these previous operations.We have analyzed the actual applications and can find that the possibility of undoing the previous editing operationsbecause of locking conflict is very little. So this concurrency controlling algorithm has virtues of quick response, nicedata consistency maintenance etc.展开更多
文摘Traditional locking mechanism is fit for the concurrency controlling and data consistency maintenance undercentralized architecture, but its response is slow, so it can not be used as concurrency controlling strategy for real-time distributed cooperative editing system. Moreover, operation transformation and data consistency maintenancetechnology are able to assure of quick response and unconstraint, but can't solve the context-specific inconsistencyproblems. Enlightened by the idea of operation transformation and optimistic locking mechanism, we bring forwardthe concurrency control algorithm of optimistic locking based on relative position. In this algorithm, the start positionof locking region and the position of operation are relative, and they are not transformed into absolute position untiloperations are sent to cooperative sites. Furthermore, any coeditor can edit in advance before his/her locking is con-firmed. If his/her locking is successful, the previous operations go into effect, or else undo these previous operations.We have analyzed the actual applications and can find that the possibility of undoing the previous editing operationsbecause of locking conflict is very little. So this concurrency controlling algorithm has virtues of quick response, nicedata consistency maintenance etc.
文摘协同系统越来越多的在各部门、企业中使用,基于智能客户端(Smart Client)的协同系统是现在协同系统发展的新趋势。它支持多用户的离线和在线的操作,将具体计算工作在客户端完成,减轻了服务器的负载,同时降低了对网络的传输要求,系统的适用范围也更广泛。通过对RBAC(Role Base Access Control)模型的改进,有效的增强了基于智能客户端环境下的RBAC访问控制,提高了系统的访问效能。
