Block Diagram - Overview

A Block diagram describes the compositional structure of a system as a composition of collaborating system components. A Block diagram consist of active components, called Agents, that perform operations visible on passive components, called Locations, which save the information processed by the agents. Locations are divided into two categories namely Storages and Channels. Agents may store information to Storages and transmit information to other agents via Channels.

Agents

An Agent represents an active component of a system. It can read from or write to a Storage and exchange information with other Agents using a Channel or shared Storage. Only passive components may be connected to Agents.
Agent
L-Agent
U-Agent
Human Agent

Storage

A Storage represents a passive component of a system. Agents can read from it or write to it. Storage that is accessed by at least two Agents is called shared storage.
Storage
L-Storage
U-Storage

Accessors

Agents use accessors to read or write information from / to a channel or storage.
Read / Write Access direct, horizontal and vertical (Note: the horizontal and vertical shapes are both of the same auto-layout type, only having a different initial state)
Read/Write L,S Access horizontal, vertical
Modifying Access direct, horizontal and vertical (Note: the horizontal and vertical shapes are both of the same auto-layout type, only having a different initial state)

Channels and Connections

Agents use Channels to exchange, transmit or broadcast information to other Agents. Channels do not store the information persitently.
Channel
Bidirectional Connection direct, horizontal and vertical (Note: the horizontal and vertical shapes are both of the same auto-layout type, only having a different initial state)
Communication Channel direct, horizontal and vertical (Note: the horizontal and vertical shapes are both of the same auto-layout type, only having a different initial state)
Universal Communication Channel horizontal, vertical

Misc

Structure Variance
Request / Response
Protocol Boundary

Shared

These masters are part of all stencil sets, not only Block Diagram
Dots
Brace
Annotation
Title Block
Frame & Title Block