E: a visual language for virtual instruments system

摘要

Visual development environments such as Lab View and Agilent VEE allow users to develop their virtual instruments (VIs) quickly and intuitively. Both the software development tools are based on dynamic homogeneous dataflow (DHDF) visual language. But the pure data-driven DHDF model has two demerits when working on a single processor system: one is that it needs a dynamic scheduler to schedule the nodes continually and circularly, which consumed almost all the CPU resource; the other is it can't react to interrupt (or event) in an event-driven operating systems that are ubiquitous. A visual language E based on an event-triggered concurrent dataflow (ECDF) model is presented in this paper. The dataflow scheduler in E stops when there is no node ready for execution and can be activated by a data-ready event. This operating mechanism leads to two advantages: the efficiency using of CPU and high responding speed to external events.