ERD (entity relationship diagram) is a graphical representation of database components. That is, it’s the blueprint of the database, and its purpose is to show rules about the meaning and interrelationships among data. A conceptual representation is derived from the ERD to create an abstract DB structure that represents real-world objects in the most realistic way possible.

Logical representation (model), which is software-dependent, is the translation of the conceptual database presentation into the internal model for the selected DBMS (such as Access, Oracle, DB2 etc). Here specifications such as tables, views, indexes, transactions, user access authorizations etc are declared.
Some of the Activities involved:
·    Derive relations for logical representation (data model)
·    Validate relations using data normalization
·    Validate relations against user transactions
·    Check integrity constraints
·    Review logical data model (ERD) with the users

Then the logical data model will be transformed into a physical data model, which reflects the technical capabilities and limitations of the selected hardware environment.
Some of the Activities involved at this level:
·    Translate the logical data model for the target DBMS
·    Design files organizations and indexes, disk space requirements
·    Design and implement user views and security mechanisms
·    Consider the introduction of controlled redundancy
·    Monitor and tune the operational system

Then during the implementation process, special storage-related constructs to house the end-user tables are created. Which might includes storage group, table space, and the tables.

References:

Logical Versus Physical Database Modeling
http://www.developer.com/tech/article.php/641521

B a r b a r a A . C a r k e n o r d, Why Build A Logical Data Model:  “T h e K n o w l e d g e E x c h a n g e C o m p a n y 770-612-0020”
http://www.embarcadero.com/resources/tech_papers/datamodel.pdf

Greenwald, R., Stackowiak, R., & Stern, J. (2004). Oracle essentials 3rd. Oracle 10
Sebastropol, CA: O'Reilly.

Rob, P. & Coronel, C. M. (2004). "Database Systems: Design, Implementation, & Management, 6th Ed." Massachusetts: Thomson Technology