I know this is a DOS question, which may not be suited here. If this is not welcome, just let me know.

I encountered this SWITCHES=/I line in the config.sys file in the IBM SGKT. Exact location follows:

ibm_sw_sgtk_1_3_07_anyos_anycpu.zip\sgdeploy\sgtk\DOS\cfgfiles\CONFIG.SYS

The ZIP file can be downloaded publicly from IBM official site: https://www.ibm.com/support/pages/ibm-serverguide-scripting-toolkit-dos-edition-version-1307

It contains a set of files, which are usually considered as a set of files to upgrade PC-DOS 2000 to PC-DOS 7.1.

I can not find any information regarding this line in the CONFIG.SYS. This is special to PC-DOS 7.1,I think.

Some preliminary experiments shows that this line seems to affect the 32BFA of WFWG. When this line is missing, WFWG can not enable 32BFA even on a FAT16 partition. When this line is added, the 32BFA is OK in WFWG.

Anyone here know about the function of this line SWITCHES=/I in PC-DOS 7.1 ? 

I've never tried it, but the "PC-Dos Viewer" looks like Pc-Dos' version of a help/information tool. Maybe try it out.