Like Dwight suggests, HD is a pretty wide concept. Since this is posted under vintage perhaps they are MFM, in which case you need to sort out the matching card if you want to read them. That could be troublesome, but as Chuck(G) points out, it could be even worse.
For looking at old disks I personally prefer dm.com (8Kb) from Michael Mefford (via PC-mag). I've explored hundreds of unknown hdds and thousands of "thrift store floppies" with that. I type pretty fast and it's the only program I know which can keep up with me on an explore. I move around by cding and hit dm to view when I see an interesting directory. Just put it on a bootable DOS floppy. Although those are the only 4 files you need (DOS and DM), throwing in cat, whereis, and particularly attrib could be handy. Attrib is a great substitute for the dir command. I particularly like the one by Charles Dye which comes from FreeDOS. A similar program to dm (dirmagic) which is a little slower to use, but much more sophisticated, is Verne Beug's list.com (27Kb).