Why fdisk can't open root disk with MBR for writing?

[Julian H. Stacey]

This is a resend as Benjamin Kaduk <kaduk at mit.edu>
dropped the 
	Yuri <yuri at rawbw.com>
from CC line, & Yuri was the original first poster in thread who
my patch would presumably have helped.

Reference:
> From:		Benjamin Kaduk <kaduk at mit.edu> 
> Date:		Sat, 15 Sep 2012 14:49:41 -0400 (EDT) 
> Message-id:	<alpine.GSO.1.10.1209151448200.861 at multics.mit.edu> 

Benjamin Kaduk wrote:
> On Sat, 15 Sep 2012, Julian H. Stacey wrote:
> 
> > I have been applying this diff to my man fdisk:
> >
> > http://berklix.com/~jhs/src/bsd/fixes/FreeBSD/src/gen/sbin/fdisk/
> >
> > *** 8.0-RELEASE/src/sbin/fdisk/fdisk.8	Sat Mar 14 22:32:16 2009
> > --- new-generic/src/sbin/fdisk/fdisk.8	Sat Mar 14 22:35:10 2009
> > ***************
> > *** 462,464 ****
> > --- 462,468 ----
> >  The
> >  .Xr bsdlabel 8
> >  command must be used for this.
> > + .Pp
> > + When running multi user, you cannot write unless you first run this:
> > + .br
> > + sysctl kern.geom.debugflags=16
> >
> > I never submitted it as a send-pr,
> > anyone think I should submit it to help save people ?
> 
> We have had a long discussion about kern.geom.debugflags starting here:
> http://lists.freebsd.org/pipermail/freebsd-current/2011-October/028090.html
> My understanding from that discussion is that your patch should not be 
> accepted.

Got to travel now, will read that thread later,

A shame if we would leave fdisk crippled undocumented, when so easy
to doc. the solution. Fdisk is known across many OSs Unix & beyond,
our BSD tools may be better nicer, but fdisk it what many will first
reach for,
 a shame not to help newer people & visitors used to fdisk.
We inside FreeBSD crippled fdisk by adding these flags. Outsiders
wont expect the weirdness & get impression FreeBSD has a bug.

Cheers,
Julian
-- 
Julian Stacey, BSD Unix Linux C Sys Eng Consultant, Munich http://berklix.com
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