Capacity · The constraint · Element
The queue
Where work is waiting.
The part
What it is
Counted rather than estimated: how many pieces are sitting at each step right now.
The step with the longest queue is the constraint, and it stays the constraint until it is relieved.
The smallest level
The attributes it carries
Each attribute is one of the framework’s shared types. What a date is, and how it is written, is defined once for the whole model — the note here says what it means in this particular place.