Data set and file are comparable terms. If you are familiar with MVS™, you probably use the term Data set to describe a unit of data storage. If you are familiar with AIX® or UNIX, you probably use the term file to describe a named set of records stored or processed as a unit. In the TCP/IP environment, in addition to the traditional MVS data set organizations (such as sequential and partitioned), UNIX files are arranged in a hierarchical directory structure.
Some MVS data sets and UNIX files have special importance because of their function. For example, certain data sets and files are used when configuring the TCP/IP environment. Other data sets are used by the Telnet server when performing specific communication functions. For descriptions of the MVS data sets and UNIX files necessary for configuring the TCP/IP environment and the search orders used to find them, see Table 1. A search order can include both MVS data sets and UNIX files, and these MVS data sets and UNIX files are collectively referred to as the configuration files in this information.