A Data Server/Services node is a generic data storage node that provides managed, persistent storage of any type of data and a means to directly access and manipulate that data. The data may be stored in files and accessed through file I/O routines or may be stored in a database with more structured and managed access methods.

A population node is a specialized application or data server that is optimized for record-oriented processing where the records must be gathered from one or more source data sets, processed singly and multiply and finally applied to one or more target data sets. A population node typically operates in an "off-line" mode to prepare data in advance of its business usage and based on rules that have been previously defined through a separate user interface module and stored in a metadata repository.

A population server may be further specialized for one or two of its inherent sub-functions--gather, process or apply (also known as extract, transform and load respectively). Such specialization may be for reasons of performance or physical placement.