diff options
Diffstat (limited to 'sbin/fdisk/fdisk.8')
| -rw-r--r-- | sbin/fdisk/fdisk.8 | 49 |
1 files changed, 17 insertions, 32 deletions
diff --git a/sbin/fdisk/fdisk.8 b/sbin/fdisk/fdisk.8 index 0db0bfe73b9..804f2ae87fb 100644 --- a/sbin/fdisk/fdisk.8 +++ b/sbin/fdisk/fdisk.8 @@ -1,4 +1,4 @@ -.\" $OpenBSD: fdisk.8,v 1.82 2015/09/06 09:06:23 jmc Exp $ +.\" $OpenBSD: fdisk.8,v 1.83 2015/09/09 15:13:35 deraadt Exp $ .\" .\" .\" Copyright (c) 1997 Tobias Weingartner @@ -15,7 +15,7 @@ .\" ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF .\" OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. .\" -.Dd $Mdocdate: September 6 2015 $ +.Dd $Mdocdate: September 9 2015 $ .Dt FDISK 8 .Os .Sh NAME @@ -35,38 +35,23 @@ .Op Fl l Ar blocks .Ar disk .Sh DESCRIPTION -On the i386 and other architectures, sector 0 of a bootable hard disk -must contain MBR bootcode, the MBR partition table containing 4 slots, -and a specific magic number (0xAA55). -The 4 slots in the MBR partition table allow a disk drive to be -divided into chunks known as MBR partitions. -.Pp -On the i386, the BIOS loads sector 0 of the boot disk into memory, -verifies the magic number, and begins executing the MBR bootcode -at the first byte. -The MBR bootcode then searches the MBR partition table for an -.Dq active -MBR partition (indicated by a -.Ql \&* -in the first column), and if one -is found, the boot block from that MBR partition is loaded and executed in -place of the original (MBR) boot block. -.Pp -Some other architectures (like the zaurus), consider sector 0 of the disk -to contain the MBR partition table, but do not use the MBR bootcode at all. +.Nm fdisk +makes changes to the MBR table found on some disks. +On such disks sector 0 contains a 4-entry MBR partition table +that divides the space. .Pp -Upon first access to a disk, the partition information is retrieved, -typically in -.Xr disklabel 5 -format. -The location of the disklabel can vary from architecture to architecture, -but if one is not found the existence of an MBR partition table will create -a spoofed prototypical disklabel which can be viewed using +Each entry has a type. +A type of +.Ar 0xA6 +indicates an OpenBSD MBR partition, which starts with its own +16-entry partition table known as a +.Xr disklabel 5 . +This can be edited using .Xr disklabel 8 . -This spoofing mechanism is useful for permitting partition access for -devices which would not normally have a -.Xr disklabel 5 -sector. +.Pp +Caution is advised when editing these tables, since some platforms +use tricks to boot and may rely on specific configurations created +at install time. .Pp The options are as follows: .Bl -tag -width Ds |