Subject: Re: 32 bit dev_t
To: Darren Reed <>
From: Chris G. Demetriou <>
List: tech-kern
Date: 01/15/1998 16:32:55
> In some mail I received from Chris G. Demetriou, sie wrote
> > 
> > My suggestion here is "do it the way BSDI did'.
> > 
> > Like I said, I'm just not particularly concerned about MAKEDEV/mknod
> > compatibility.
> > 
> > Having 'dv_unit()' and 'dv_subunit()' in the kernel would be a good
> > idea. Also a good idea might be to rename 'minor()' in the kernel to
> > 'dv_minor()', so that no devices will ever try to use the old
> > semantics of minor numbers again w/o being inspected.
> we really need to do that ?

No, but on the other hand as long as 'minor' is used, there could be
problems with the device trying to interpret the minor numbers the
wrong way.

> > There's only so much in the way of semantic freedom a given device
> > should have in interpreting its device nodes.  'real' devices should
> > use 'dv_unit()' to figure out which device unit is being accessed.
> > dv_subunit() usage should be device dependent, but should be
> > as consistent as possible within classes of devices.
> > 
> > I'm not even so convinced that things like BPF, which BSDI allowed to slide
> > by using the old minor() should be allowed to do so.
> And what would you have had them do in this case instead of that ?

I think i'd say "use dv_unit() for that."