If we can agree on this: User Interfaces -----------------> Front-endware _______________ Definitions | Brokers |------> Middleware Processors _______________| Objects and Applications --------> Back-endware then DL, BL and PL are all 'layers' of the 'middleware' that you are writing the IDL for. And we can probably continue to say 'front' and 'back' as we did with Loci. Jeff -- +----------------------------------+ | J.W. Bizzaro | | | | http://bioinformatics.org/~jeff/ | | | | BIOINFORMATICS.ORG | | The Open Lab | | | | http://bioinformatics.org/ | +----------------------------------+