I did figure out a little of the SDA offsets a long while back , see https://github.com/dosemu2/dosemu2/blob/a3d2ce995f240f3c5c7fa5e130244c7e771befdb/src/dosext/mfs/mfs.c#L1391. You can see that there are even differences between the DOS v3 variants that I tested, though I'm not sure that I nailed everything, just enough for the Dosemu redirector to work with old DOSes.
Originally posted by @andrewbird in #103 (comment)
Originally posted by @andrewbird in #103 (comment)