Subject: Re: dev_t changes & partitions
To: Henry W Miller <>
From: Todd Vierling <tv@NetBSD.ORG>
List: tech-kern
Date: 01/15/1998 12:46:28
On Thu, 15 Jan 1998, Henry W Miller wrote:

: If we deprecate old major nmbers, can we have the kernel look for the new
: major number for a device, and if there is a new style major pointing to
: the device then ignore any old style major numbers that might exists on
: the disk?  As others have pointed out, it is sometimes nessicary to move
: back to an old kernel when serious bugs show up.  (don't they always wait
: until after beta finishes?)  

Why should the old nodes be ignored?  16 bit devices will be converted to 32
bit devices in the faith that the same name node (say /dev/rsd1h) will
function identically as its 32 bit counterpart.  The extra bits, which would
otherwise be 0 by default, would obviously need different names anyway.

The quick summary/fix:  just use 16 bit nodes for any device name that
already exists, and only add 32 bit nodes where you don't have some already.
You can then fall back any time you want to.

: I guess one potential problem with this would be if the old kernels seee
: the new_style major (perhaps in corrupted form) and either trys to fix
: them, or barfs on them.

The old kernels will barf on new nodes, but then, if they represent devices
taking advantage of new bits it should barf on them anyway, right?  :)  Yes,
there will be care required on your part if you start using real 32 bit
nodes and plan on having fallback ability.

===== Todd Vierling (Personal =====
== "There's a myth that there is a scarcity of justice to go around, so
== that if we extend justice to 'those people,' it will somehow erode the
== quality of justice everyone else receives."  -- Maria Price