| 摘要 |
A point-of-sale transaction processing system (1, 10, 30) may be used in a versatile manner either directly at points-of-sale or at a retailing back-office. The system has a controller (34) which has initialisation, processing, external communications, and reply modules which operate autonomously. Control is passed between the modules in a cyclic manner by a scheduler, however, each module controls the length of time during which it operates in each cycle. Messages are passed between the modules to progress a transaction through the controller. The messages are written to dedicated queues in memory for the reply modules. |
