Greg A. Woods says:
> I agree, if it works, having separate dial-in/dial-out devices, with all
> the access control in the driver, is handy.
> 
> However most every implementation I've used has some problems with
> permitting multiple open()s on such devices, since the driver writer
> often gets the semantics wrong.

The Sun implementation seems worked just fine, and handles the
semantics very well. I've used this for at least six years without any
trouble.

> And finally, as I've said all along, the lock state is maintained in the
> kernel, and the user has little option but a re-boot if anything goes
> wrong.

Many buggy things have that property -- the solution is just to make
the implementation non-buggy.

> BTW, I think having multiple tape/floppy devices for different densities
> is an icky hack too

Perry