CompuServe Drives: Custom firmware?

[Eric Smith]

On Sat, Apr 18, 2015 at 12:42 AM, Cory Smelosky <b4 at gewt.net> wrote:
> ...or it could be that the drives are definitely HVD and none of my
> controllers actually are - even the buggy one that claims it might be!

My fuzzy recollections are that ND is 8-bit single-ended, and WD is
16-bit "ultra" (low voltage differential). LVD drives usually (perhaps
always?) can fall back to single-ended operation. Single-ended drives
won't do any form of differential under any circumstances.