Subject: Re: 32 bit dev_t, Revision 2
To: Manuel Bouyer <>
From: Chris G. Demetriou <>
List: tech-kern
Date: 01/12/1998 09:13:39
> On Jan 11, Chris G. Demetriou wrote
> > This is fine by me.  If people want more major bits, that'd be fine by
> > me, too, but most of the systems I use use 12/20.
> > 
> > I like 20; i can easily imagine using 20 minor bits.
> > 
> > 8 bits to select a SCSI bus, 4 to select a target, 3 to select at LUN,
> > 5 to select a parptition.  8-)
> > 
> > 
> Is 16 targets/bus enougth for future SCSI and SCSI-like standarts ?

Maybe not, but i'm not trying to wire that down that way, anyway.  (In
particular, i like the way device unit allocation is done now -- if
people want to wire things down, they can, but there's no fixed
partitioning of the device minor numbers based on attributes of the
SCSI bus.)

I can easily imagine having Lots of fully populated SCSI busses on a
large machine.  Granted, they're probably not be so populated as to
need _all_ of those units, but hey, if you've got a lot of raid
controllers...  8-)

My point was that 20 bits was something which i could imagine a system
using without _too_ much difficulty.