On 15 Jan 1998, Charles M. Hannum wrote:

: > - ls(1) prints devices in major-`unit'-`subunit' format (12/12/8 bits).  In
: >   this arrangement, 16-bit device nodes show up as `0,major,minor'.
: 
: Of course, with my proposal, the old device numbers split correctly,
: and this isn't a problem.  No need to teach ls(1) anything new.

No need to teach ls(1) anything if it just pulls major() and minor() from
<sys/types.h>.  You have breakage in any case if you have ls(1) using old
major and minor formats and new nodes... you may get correct major numbers
with a split format, but you have wrong minor numbers anyway.

I still have yet to see what splitting the minor number *gains us*.  We can
go without, and still be just as transparent in compatibility.  And we don't
lose N major numbers; just one.

: > - mknod(8) will make 16-bit device nodes (or N bit device nodes, depending
: >   on command line switches) if passed two numerical arguments.  It will make
: >   32 bit device nodes if passed three numerical arguments in
: >   `major unit subunit' format.
: 
: And no need to do this.  I especially wonder how many standards this
: violates.

I don't know; you're the standards guru and I'd love to know.  BSDI does a
variation of this, according to Chris Torek....

: Again, you're making this more complicated than it needs to be.

How?

Adding stuff to ls(1) and mknod(8) is just one of many ways of implementing
larger devices in user tools.  I proposed one way, and I've already proposed
(in the past) the "more standard" way that just accepted a major and minor
numbers that are bigger--that's more or less just a transparent upgrade.

The alternatives of splitting up the minor is, in my opinion, just an easier
mnemonic for end-users.  Remember, I still don't advocate forcing the minor
number split on any of kernel--just for mknod and ls.  I'm still using
major() and minor() in my test code. 

Would you rather remember the node numbers in:

brw-r-----  1 root  operator    17,0,0 May 26  1997 /dev/sd0a
brw-r-----  1 root  operator    17,0,1 May 26  1997 /dev/sd0b
brw-r-----  1 root  operator    17,1,0 May 26  1997 /dev/sd1a
brw-r-----  1 root  operator    17,1,7 May 26  1997 /dev/sd1h
brw-r-----  1 root  operator    17,4,2 May 26  1997 /dev/sd4c

or:

brw-r-----  1 root  operator   17,   0 May 26  1997 /dev/sd0a
brw-r-----  1 root  operator   17,   1 May 26  1997 /dev/sd0b
brw-r-----  1 root  operator   17, 256 May 26  1997 /dev/sd1a
brw-r-----  1 root  operator   17, 263 May 26  1997 /dev/sd1h
brw-r-----  1 root  operator   17,1026 May 26  1997 /dev/sd4c

?  That's the reason for the ls/mknod split.

=====
===== Todd Vierling (Personal tv@pobox.com) =====
== "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