Timing

To understand MontiArc you need to know about timings and how they affect components. Multiple time abstractions are available in MontiArc. We briefly introduce the different timing concepts here. MontiArc is based on the mathematical FOCUS¹ framework, which provides clear semantics.

In MontiArc time is split into equidistant time intervals, where each interval has a finite number of messages. The granularity of time, i.e., length of intervals, is not modeled and depends on the system's context. The timing can be described by streams, which contain ordered messages. A pseudo-message called tick separates the time intervals.

During modeling, timings are specified on a per port basis.

Timed

The timed timing specification uses events over ports. It is suited for asynchronous communication.

Components can directly react to these events.

block-beta
  block:id1
    columns 1
    style id1 fill:None,Stroke:None
    blockArrowId1<["<code><0, tick, 3, tick></code>"]>(right)
    blockArrowId2<["<code><&nbsp&nbsp tick, 1, tick></code>"]>(right)
    blockArrowId3<["<code><4, tick, &nbsp&nbsp tick></code>"]>(right)
  end
  Component

Synchronous

The alternative to timed is synchronous communication. Here all messages over ports are sent and received at the same time once every time interval. Events in this time domain are tuples over all synchronous ports of a component.

A component can only react to sync messages once all sync ports have received their message. I.e., the input time frame is complete.

block-beta
  block:id1
    style id1 fill:None,Stroke:None
    block:id2
      style id2 fill:None,Stroke:None
      blockArrowId<["<code>0 &nbsp&nbsp&nbsp&nbsp&nbsp&nbsp 6 &nbsp&nbsp&nbsp&nbsp&nbsp<br/><3, tick, 2, tick><br/>4 &nbsp&nbsp&nbsp&nbsp&nbsp&nbsp 6 &nbsp&nbsp&nbsp&nbsp&nbsp</code>"]>(right)
    end
  end
  Component

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1. Manfred Broy and Ketil Stølen. Specification and Development of Interactive Systems. Focus on Streams, Interfaces and Refinement. Springer Verlag Heidelberg, 2001. ↩