It deals in Software Development Cycle. It processes in various types of software development cycles
This deals with backend databases to store the information.
This layer determined as the interaction b/w front end and back-end.
That Uses DNA Architecture:
It is also called Monolithic approach. It has achieved DNA but demerit is that expansion is harmful in future for mainframe.
UNIX posses 1-tier architecture.
For different type of technologies here is DCOM