Not sure if this is fully relevant, I always pick up on any ADF diddling.
http://www.bitsavers.org/pdf/sco/system_V_2.3.4/SCO_XENIX_System_V_Operating_System_Release_Notes_2.3.4_Aug1991.pdf
page 165 physical
Although your IBM 6157 tape installs successfully, you may see
the following error message when your system boots up:
WARNING: first reset no good
ERROR: tape controller (type X) not found
To correct this error, you need to inspect the DOS reference file
@DFBF.ADF. This file is found on the IBM reference diskette, and
contains configuration details for microchannel tape controllers.
The file should read as follows:
Adapterld ODFBFh
AdapterName "Streaming Tape Adapter Card"
NumBytes 2
FixedResources
POS[O]=OOOOOlOXb
POS[l]=OOOOOOlOb
io 3120h-312fh
int 6
If your file differs in any way from the above, modify it accordingly.
We have:
https://www.ardent-tool.com/adapters/adf/@dfbf.adf
FixedResources
pos[0]=00000X0Xb
pos[1]=0000XXXXb
io 3120h-312fh
int 6
--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)