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diff --git a/diskdev_cmds/fdisk.tproj/fdisk.8 b/diskdev_cmds/fdisk.tproj/fdisk.8 new file mode 100644 index 0000000..c74c091 --- /dev/null +++ b/diskdev_cmds/fdisk.tproj/fdisk.8 @@ -0,0 +1,377 @@ +.\" $OpenBSD: fdisk.8,v 1.38 2002/01/04 21:20:56 kjell Exp $ +.\" +.\" Copyright (c) 2002 Apple Computer, Inc. All rights reserved. +.\" +.\" "Portions Copyright (c) 2002 Apple Computer, Inc. All Rights +.\" Reserved. This file contains Original Code and/or Modifications of +.\" Original Code as defined in and that are subject to the Apple Public +.\" Source License Version 1.2 (the 'License'). You may not use this file +.\" except in compliance with the License. Please obtain a copy of the +.\" License at http://www.apple.com/publicsource and read it before using +.\" this file. +.\" +.\" The Original Code and all software distributed under the License are +.\" distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER +.\" EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, +.\" INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, +.\" FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the +.\" License for the specific language governing rights and limitations +.\" under the License." +.\" +.\" Copyright (c) 1997 Tobias Weingartner +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" 3. All advertising materials mentioning features or use of this software +.\" must display the following acknowledgement: +.\" This product includes software developed by Tobias Weingartner. +.\" 4. The name of the author may not be used to endorse or promote products +.\" derived from this software without specific prior written permission. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR +.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES +.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. +.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, +.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT +.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF +.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +.\" +.Dd January 3, 2002 +.Dt FDISK 8 +.Os +.Sh NAME +.Nm fdisk +.Nd DOS partition maintenance program +.Sh SYNOPSIS +.Nm fdisk +.Op Fl ieu +.Op Fl f Ar mbrname +.Op Fl c Ar cylinders +.Op Fl h Ar heads +.Op Fl s Ar sectors +.Op Fl S Ar size +.Op Fl b Ar size +.Ar device +.Sh DESCRIPTION +In order for the BIOS to boot the kernel, certain conventions must be +adhered to. +Sector 0 of a bootable hard disk must contain boot code, +an MBR partition table, and a magic number (0xAA55). +These MBR partitions (also +known as BIOS partitions) can be used to break the disk up into several +pieces. +.Pp +The BIOS loads sector 0 of the boot disk into memory, verifies +the magic number, and begins executing the code at the first byte. +The normal DOS MBR boot code searches the MBR partition table for an +.Dq active +partition (indicated by a +.Ql \&* +in the first column), and if one +is found, the boot block from that partition is loaded and executed in +place of the original (MBR) boot block. +.Pp +The options are as follows: +.Bl -tag -width Ds +.It Fl i +Initialize the MBR sector. +.It Fl a Ar style +Specify an automatic partitioning style. +.It Fl e +Edit existing MBR sectors. +.It Fl f Ar mbrname +Specifies an alternate MBR template file. +.It Fl u +Update MBR code, preserving existing partition table. +.It Fl y +Do not ask for confirmation before writing. +.It Fl d +Dump partition table in a format readable by the -r option. +.It Fl r +Read a partition table from the standard input. +.It Fl t +Test if the disk is partitioned. +.It Xo Fl c Ar cylinders , +.Fl h Ar heads , +.Fl s Ar sectors +.Xc +Specifies an alternate BIOS geometry for +.Nm +to use. +.It Fl S Ar size +Specify the disk size in blocks. +.It Fl b Ar size +Specify the number of bytes per disk block. +.El +.Pp +The DOS +.Nm +program can be used to divide space on the disk into partitions and set +one active. +This +.Nm +program serves a similar purpose to the DOS program. +When called with no special flags, it prints the MBR partition +table of the specified device, i.e., +.Bd -literal + # fdisk fd0 + Disk: fd0 geometry: 80/2/18 [2880 sectors] + Offset: 0 Signature: 0xAA55 + Starting Ending + #: id cyl hd sec - cyl hd sec [ start - size] + ---------------------------------------------------------------------- + *1: A6 0 0 1 - 79 1 18 [ 0 - 2880] OpenBSD + 2: 00 0 0 0 - 0 0 0 [ 0 - 0] unused + 3: A7 0 0 2 - 79 1 18 [ 1 - 2879] NEXTSTEP + 4: 00 0 0 0 - 0 0 0 [ 0 - 0] unused +.Ed +.Pp +The geometry displayed is a synthetic geometry unless another geometry +has been selected using the +.Fl c , +.Fl h , +.Fl s , +.Fl S , +and +.Fl b +options. +In the future, +.Nm +will read the BIOS geometry from the IOKit registry. +.Pp +In this example, +the disk is divided into two partitions that happen to fill the disk. +The first partition overlaps the third partition. +(Used for debugging purposes.) +.Bl -tag -width "start/size" +.It Em "#" +Number of partition table entry. +A +.Dq \&* +denotes the bootable partition. +.It Em "id" +System identifier. +.Ox +reserves the +magic number 166 decimal (A6 in hex). +If no 166 partition is found, it will use an older +.Fx +partition (with a magic number of 165 or A5 in hex). +.It Em "cyl/hd/sec" +These fields provide the starting and ending address of the partition +in BIOS geometry +.It Em "start/size" +These fields provide the starting sector and size in sectors of the +partition in linear block addresses. +.El +.Pp +.Em NOTE : +The sectors field is +.Dq 1 based , +and the start field is +.Dq 0 based . +The CHS values may need to be in the BIOS's geometry +for older systems to be able to boot and use the drive correctly; +most modern systems prefer the starting sector and size +in preference to the CHS values. +.Pp +The +.Fl i +flag is used to indicate that the partition data is to be initialized. +In this mode, +.Nm +will completely overwrite the primary MBR and partition table, either +using the default MBR template, or the one specified by the +.Fl f +flag. +.Pp +In the default template, partition number 1 will be configured as a +Darwin boot +partition spanning from cylinder 0, head 1, sector 1, and extending +for 8 megabytes. +Partition number 2 will be configured as a +Darwin HFS +partition spanning the rest of the disk. +This mode is designed to initialize an MBR the very first time, +or when it has been corrupted beyond repair. +.Pp +You can specify other default partition styles with the +.Fl a +flag. The available styles are: +.Bl -tag -width "start/size" +.It Em "boothfs" +Creates an 8Mb boot partition (type AB hex) +and makes the rest of the disk +a Darwin HFS partition (type AF hex). +.It Em "hfs" +Makes the entire disk one HFS+ partition (type AF hex). +.It Em "dos" +Makes the entire disk one DOS partition (type 0C hex). +.It Em "raid" +Makes the entire disk one type AC hex partition. +.El +.Pp +The +.Fl u +flag is used to update the MBR code on a given drive. +The MBR code extends from offset 0x000 to the start of the partition table +at offset 0x1BE. +It is similar to the +.Fl i +flag, except the existing partition table is preserved. This +is useful for writing new MBR code onto an existing drive, and is +equivalent to the DOS command +.Dq FDISK /MBR . +Note that this option will overwrite the NT disk signature, if present. +The +.Fl u +and +.Fl i +flags may not be specified together. +.Pp +The flag +.Fl e +is used to modify a partition table using a interactive edit mode of the +.Nm +program. +This mode is designed to allow you to change any partition on the +drive you choose, including extended partitions. +It is a very powerful mode, +but is safe as long as you do not execute the +.Em write +command, or answer in the negative (the default) when +.Nm +asks you about writing out changes. +.Sh COMMAND MODE +When you first enter this mode, you are presented with a prompt, that looks +like so: +.Em "fdisk: 0>" . +This prompt has two important pieces of information for you. +It will tell +you if the in-memory copy of the boot block has been modified or not. +If it has been modified, the prompt will change to look like: +.Em "fdisk:*0>" . +The second piece of information pertains to the number given in the prompt. +This number specifies the disk offset of the currently selected boot block +you are editing. +This number could be something different that zero when +you are editing extended partitions. +The list of commands and their explanations are given below. +.Bl -tag -width "update" +.It Em help +Display a list of commands that +.Nm +understands in the interactive edit mode. +.It Em manual +Display this manual page. +.It Em reinit +Initialize the currently selected, in-memory copy of the +boot block. +.It Em auto +Partition the disk with one of the automatic partition styles. +.It Em disk +Display the current drive geometry that +.Nm +has +probed. +You are given a chance to edit it if you wish. +.It Em edit +Edit a given table entry in the memory copy of +the current boot block. +You may edit either in BIOS geometry mode, +or in sector offsets and sizes. +.It Em setpid +Change the partition +identifier of the given partition table entry. +This command is particularly useful for reassigning +an existing partition to OpenBSD. +.It Em flag +Make the given partition table entry bootable. +Only one entry can be marked bootable. +If you wish to boot from an extended +partition, you will need to mark the partition table entry for the +extended partition as bootable. +.It Em update +Update the machine code in the memory copy of the currently selected +boot block. +Note that this option will overwrite the NT disk +signature, if present. +.It Em select +Select and load into memory the boot block pointed +to by the extended partition table entry in the current boot block. +.It Em print +Print the currently selected in-memory copy of the boot +block and its MBR table to the terminal. +.It Em write +Write the in-memory copy of the boot block to disk. +You will be asked to confirm this operation. +.It Em exit +Exit the current level of +.Nm fdisk , +either returning to the +previously selected in-memory copy of a boot block, or exiting the +program if there is none. +.It Em quit +Exit the current level of +.Nm fdisk , +either returning to the +previously selected in-memory copy of a boot block, or exiting the +program if there is none. +Unlike +.Em exit +it does write the modified block out. +.It Em abort +Quit program without saving current changes. +.El +.Sh NOTES +The automatic calculation of starting cylinder etc. uses +a set of figures that represent what the BIOS thinks is the +geometry of the drive. +These figures are by default taken from the in-core disklabel, or +values that +.Em /boot +has passed to the kernel, but +.Nm +gives you an opportunity to change them if there is a need to. +This allows the user to create a bootblock that can work with drives +that use geometry translation under a potentially different BIOS. +.Pp +If you hand craft your disk layout, +please make sure that the +.Ox +partition starts on a cylinder boundary. +(This restriction may be changed in the future.) +.Pp +Editing an existing partition is risky, and may cause you to +lose all the data in that partition. +.Pp +You should run this program interactively once or twice to see how it works. +This is completely safe as long as you answer the +.Dq write +questions in the +negative. +.Sh FILES +.Bl -tag -width /usr/mdec/mbr -compact +.It Pa /usr/mdec/mbr +default MBR template +.El +.Sh SEE ALSO +.Xr gpt 8 , +.Xr pdisk 8 +.Sh BUGS +There are subtleties +.Nm +detects that are not explained in this manual page. +As well, chances are that some of the subtleties it should detect are being +steamrolled. +Caveat Emptor. |