One major exception to the requirement that the software run on the mainframe is software that interfaces to the mainframe, such as 3270 mainframe terminal emulation software that runs on Windows- or Unix-based workstations but is used to connect to the mainframe.

For software companies that sell predominantly non-mainframe software, it is preferable to list a Web page other than the home page, if one exists that links to all mainframe software products.

If in doubt as to which source of software should be listed here, select the site where support is provided for the software worldwide. Not resellers or local distributors. Generally, the manufacturer.

Offerings of free software, not demos or time-limited copies, should be listed in Computers: Software: Operating Systems: Mainframe: IBM: Freeware.