From nobody@FreeBSD.org  Thu Jul 14 01:10:51 2005
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Message-Id: <200507140110.j6E1Aoq2046747@www.freebsd.org>
Date: Thu, 14 Jul 2005 01:10:50 GMT
From: Jan Slaets <jan@janot.ifsc.usp.br>
To: freebsd-gnats-submit@FreeBSD.org
Subject: fdisk can't read or write disklabel
X-Send-Pr-Version: www-2.3

>Number:         83425
>Category:       i386
>Synopsis:       fdisk can't read or write disklabel
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    freebsd-i386
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Jul 14 01:20:11 GMT 2005
>Closed-Date:    Mon Sep 12 09:02:10 GMT 2005
>Last-Modified:  Mon Sep 12 09:02:10 GMT 2005
>Originator:     Jan Slaets
>Release:        FreeBSD 5.4 - release
>Organization:
Univ. Sao Paulo - Brazil
>Environment:
i386-atlon with only one ATAPI 10Gbyte hard disc    
>Description:
     Installation process is unable to read or write fdisk and any new partition data to disk ad0 and is aborted.
The 5.4-release fails also to recognize any partition data created successfully by a 4.6.2 FreeBSD installation on the same 10Gbyte hard disk. (Done to try an upgrade procedure to 5.4)
     Disk geometry of ad0 cyl 1247 heads 255 sect 63

>How-To-Repeat:
      Always.
>Fix:
      
>Release-Note:
>Audit-Trail:

From: =?ISO-8859-1?Q?Bj=F6rn_K=F6nig?= <bkoenig@cs.tu-berlin.de>
To: Jan Slaets <jan@janot.ifsc.usp.br>
Cc: freebsd-gnats-submit@freebsd.org
Subject: Re: i386/83425: fdisk can't read or write disklabel
Date: Thu, 14 Jul 2005 03:38:59 +0200

 Hello Jan,
 
 there is a mechanism that protects the MBR from being overwritten 
 accidentally. Execute
 
    sysctl kern.geom.debugflags=16
 
 and try again.
 
 Bjrn

From: Jan Slaets <jan@janot.if.sc.usp.br>
To: bug-followup@FreeBSD.org, jan@janot.ifsc.usp.br
Cc:  
Subject: Re: i386/83425: fdisk can't read or write disklabel
Date: Thu, 14 Jul 2005 21:07:45 -0300

 <>A later Bios examination showed that the disk was
 defined in the Bios as being Cyl 19885 Head 16 Sec 63.
 Changing the disk geometry in the fdisk sysinstall FreeBSD 5.4 utility
 to this new value made the installation possible.
 Now I have however DMA sporadic access failures to ad0.
 I changed the motherboard, and with a well behaved BIOS (Head = 255)
 Now everything works.
State-Changed-From-To: open->closed 
State-Changed-By: linimon 
State-Changed-When: Mon Sep 12 09:01:44 GMT 2005 
State-Changed-Why:  
This sounds from the followup as though it was a hardware problem. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=83425 
>Unformatted:
