Validating df0: and/or df1:

[JSS3rd]

I cranked up my trusty old Amiga 2000 the other day, after not having used it for several years, and was greeted with a screen saying "Validating DF0:".  I have tried swapping cables, jumpers, everything I can think of, and all I've accomplished is that sometimes the screen says "Validating DF1:", instead.

I've tried unplugging the floppy cable from the motherboard and unplugging the power connectors from the drives, hoping that I could boot from the hard drive, but I still get the validation screen, even though the floppy drives aren't physically connected.

Can anyone shed any light on this, or has my 2000 become just a doorstop?

[JSS3rd]

DF0: and DF1: are the floppy drives, which are, apparently,  giving me the messages.  DH0: and DH1: would be either two hard drives with a single partition each, or two partitions on a single hard drive.

[JSS3rd]

This is getting more and more weird.  I left the computer on all night, doing its validation thing, but I don't remember if it said it was validating df0: or df1: (the information disappears from the screen fairly quickly).  

This morning, with a blank DOS screen showing, I shut the computer down.  When I powered up, the computer booted normally from the hard drive.  Just out of curiosity, I inserted a disk into df0: and, working in a CLI window, typed "cd df0:".  The response was "Can't find df0:".  Just to check, I inserted the same disk into df1:, repeated the command, and the drive read the disk.

So, now I seem to have df1: working properly.  Any thoughts on how to accomplish the same thing with df0: ("validate" isn't an AmigaDOS command)?

[JSS3rd]

Validate lies in any Amiga ROM (after 1.3, if I remember right).

And what, exactly, does that mean?  That if the system senses an abnormality it will attempt to correct it, but I can't do it myself?