According to "Charles M. Hannum" <mycroft@mit.edu> :
> 
> Effectively what you're doing here is using the presence or absence of
> O_NONBLOCK to distinguish between dialin and dialout use (as opposed
> to a bit in the minor number, in SunOS and some other systems).  The
> two methods are more or less isomorphic, except that the actual
> implementation of the O_NONBLOCK method in 4.4 was completely broken
> and didn't actually work.

In which case (a) the O_NONBLOCK method should be fixed (is that too 
tall a request?) and (b) if then it does the job, there might no longer 
be any need to use a a minor-number bit to achieve the same result.

I'll side with Paul, here: polluting the /dev namespace isn't a 
pleasant thought.
-- 
Lucio de Re (lucio@proxima.alt.za)
Disclaimer: I'm working at getting my opinions to agree with me.