Diagram Nessesary Conditions

[Bill Egge]

How do I diagram a nessesary condition for an event to happen?

For instance, a conversion to a new version of software is an event, but that event will not happen unless "Sally" prepares some data files the conversion depends on.

[Jan ´Bary´ Glas]

I wouldn't call that event but action, some ways:

[Bill Egge]

Thanks, that makes sense.

[Jan ´Bary´ Glas]

But if it is an event for your process, you may omit the preparation of files, your process just waits for that event to happen. (Depends on what you are modelling.)

[Bill Egge]

We cannot do the conversion without her making the datafiles.  So, it sounds like an event and a pre-condition.  An event in the sense that we are waiting on it and a pre-condition from a functional perspective.

[sargasso]

This is just the question of where the system boundary lies.  If Sally is inside the boundary e.g. she is controlled / managed by the (big s) System, then it is probablyan action/activity/process of interest to the model.  OTOH if she lies outside the boundary, i.e. the System exerts zero control over Sally then it is just an event (perhaps better modelled as "Prep'ed Data File arrives") or a pre-condition ("Prep'd Data File Available).

bruce