Turbodos on a Horizon 8/16 system

This email is short on questions; just a vintage computer putzing report. I do have one question of opinion at the end. I've had a northstar horizon 8/16 system for a year and a half now, but I was able to finally get everything together and a bit of time to get it running. The 8/16 is a normal horizon (in the aluminum cabinet, not wooden), with a beefier power supply. There may be some other mechanical differences, such as many more punchouts in the back. The purpose of the system is to host multiple CPUs running in a S-100 backplane, each with its own local memory, using the Z80 down on the motherboard to act as a server for the shared resources. As the 8/16 name implies, you can have 8b (z80) or 16b (8086) CPUs, or a mix of them. Mine has two Z80 cards, each with 64KB DRAM, in addition to the Z80 on the motherboard and 64KB DRAM that is uses on the S-100 BUS. The box has a single 5.25" floppy and a 30 MB Rodime hard drive (ST506 type interface). The way things are set up in the horizon, you can't boot directly off the hard drive; the usual procedure is to boot the floppy, and the floppy contains a bootstrap to load the OS from the hard disk. I first booted into HDOS from floppy, the hard disk version of NSDOS. It has both non-destructive and destructive disk tests. "LI" shows that there is no meaningful HDOS file system on the drive. Next, I ran only the non-destructive test since one goal is to see what is on the hard disk. HDOS, like NSDOS, has a command for reading arbitrary absolute sectors from the floppy, but it isn't supported on the hard drive -- instead you can load sectors relative to a named file, which doesn't help me here. Next I booted turbodos from floppy. "DIR" shows no meaningful file system on either of the two partitions on the drive. Finally, I'm at an impasse. I assume that this system had *something* on the drive, although I suppose a previous owner did a FORMAT on the drive before passing the system on. It would be easiest for me to just format the drive and install either HDOS, or more likely, TurboDos and get on with it. If I had more time I'd look into finding a mechanism to read the hard drive sector by sector and make a copy, but the reality is I have more projects than I have time for, so this seems unlikely. Does anybody who has read this far have an idea what to do next? Format and reinstall? Write my own driver to dump the disk first? Find an old PC with a controller card that could interface to the drive?