Subject: port-i386/13748: fdisk(8) always uses in-core boot record
To: None <>
From: Don Yuniskis <>
List: netbsd-bugs
Date: 08/18/2001 17:23:38
>Number:         13748
>Category:       port-i386
>Synopsis:       fdisk(8) fails to reread updated on-disk boot record
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-i386-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Aug 18 17:25:00 PDT 2001
>Originator:     Don Yuniskis
>Release:        NetBSD 1.5.1
Don Yuniskis
    System: NetBSD Some.Machine.Name 1.5.1 NetBSD 1.5.1 (GENERIC) #56: Mon
Jul 2 15:54:23 CEST 2001 i386
When the "master boot record" is altered with fdisk(8)
    (e.g., 'fdisk -b CC/HH/SS sd0', 'fdisk -u sd0', etc.),
    the changes are written back to disk (assuming the user
    indicates his desire to do so!).  However, subsequent
    invocations of fdisk(8) present the original parameters
    as existed prior to the alteration.  I.e. the disk is
    never reexamined.
fdisk -u sd0
    alter the "BIOS geometry"
    save the changes to disk
    fdisk -u sd0
    note BIOS geometry APPEARS to not have been changed
What's the downside to forcing a read of the physical
    media (instead of relying on in-core information)?

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