Tim Bass
07-20-2008 06:57 AM
A blackboard architectureis a distributed computing architecture wheredistributed applications, modelled as intelligent agents,share acommon data structure calledthe �blackboard�* and a scheduling/control process.* The blackboard can be either centeralized or distrbuted, depending on the requirements and constraints of the application(s).
To solve a complex problemin the blackboard-style, the intelligent agents cooperate as functional specialists, observing updates to the blackboard and self-actualizing in an event driven process)when there is new information to process. Agents continuallyupdate the blackboard with partial solutions when the agents capabilities for processingmatch the state of the blackboard.
The blackboard architecture is a distributed computing model for a*metaphordescribing how people work together to collaborativelysolve a problem around a blackboard (whiteboard in todays lingo).** For example, one person is standing at the whiteboard working on a solution while three other people are sitting (or standing) around watching.** One of the observers sees new informationon the whiteboard, thinks of howhe (or she) can*contribute,and then jumps up, takes the whiteboard marker from the person working, andadds to the solution.* This process is repeated in various scenarios.**
The blackboardarchitecture can be very effective in solving complex distributed computing problems, including event processing problems; however, scheduling the self-actuating agentscan bea key challenge.** Another core challenge is how to model and manage the blackboard itself, especially in distributed blackboard architectures.** John McManus, former CTO of NASA, wrote an excellent PhD dissertation in 1992, Design and Analysis Techniques for Concurrent Blackboard Systems, at the College of*William and Mary,*these addressing challenges in BB systems.
The table below lists two books that focus on blackboard archtecture:
Date Editor\(s\) Publisher ISBN Title 1989 V. Jagannathan et al Academic Press 0123799406 Blackboard Architectures and Applications 1988 Robert Engelmore and Tony Morgan Addison-Wesley 0201174316 Blackboard Systems One of the though leaders in blackboard architecture is [Daniel D. Corkill](http://dancorkill.home.comcast.net/~dancorkill/pubs/) a professor at the [University of Massachusetts Amherst](http://www.cs.umass.edu/~cork/).*
Blackboard architecture is*relevant to the field of event processing, and in particular complex event processing.** I will go into more details in future blog posts on this topic, including how blackboard architectures relate to grid computing, distributed object caching (of the blackboard), and CEP.