A native data set in PL/I terms defines conventional text files and devices associated with the platform you are using.
A conventional text file has logical records delimited by the CR - LF (carriage return and line feed) character sequence. Most text editor programs create, and allow you to alter, conventional text files. Your PL/I programs can create conventional text files, or they can access text files that were created by other programs.
Devices for workstation products are the keyboard, screen, and printer. The names you use to refer to them in PL/I are:
In a non-interactive environment, SYSIN and SYSPRINT can be pipes or files.