A follow up post.
I found out that all IDE drives that implement locking must also implement a security erase option/command which will overwrite the contents of the drive with zeroes and unlock the drive, so it can be used again. This is exactly what I want.

I haven't found any utilities around that will let me do this - must be some for Linux somewhere, most of the DOS/PC ones I find are part of forensics type data recovery programs thatcost $$ and I don't need that sort of tool. That will cost more than the drive.

I would gather it must be a real simple utility - all it does is send a "seceurity erase" command to the IDE drive and sit back and wait.

Any IDE kernel hackers out there? Mark any comments?