Recovering an elderly OnTrack Disk Manager DM6 drive in Linux

Among my delayed little tasks from cleaning out my grandparents'/uncle's house was seeing what I could recover from old hard drives. While there, I stripped 8 drives from 5 desktops (the historical progression of PCs since 1994), recycled the machines, and brought the drives home for possible data retrieval.

Was this necessary? Of course not. It's data-hoarding. I probably won't really go through this data in any meaningful way. Certainly not all the old copies of Win 3.1, Netscape, and Paint Shop Pro. But, hey, data's so cheap...