Thank you for the response, it gave me something to work with.

On Fri, May 05, 2006 at 03:20:59PM -0400, Brian A. Seklecki wrote:
> Probably because 99% of the drives out there where you'd want to do this 
> with have a Picker SCSI device you can use pkgsrc/sysutils/mtx or chio(1) 
> on.

I checked it out, and my drive is not attaching a picker device (ch*).
I tried chio -f /dev/rst0 status, and got "inappropriate ioctl".

> There is a similar function that "closes" the drive door on CDROMs, if 
> they support it.  Check eject(8).

I tried eject -l st0, and got "Operation not supported".

As Greg Troxel suggested, I guess it is time to source-dive the Linux
code and see how it's done.

Cheers,

Ben