On Mon, Mar 23, 2009 at 02:56:54AM +0100, frantisek holop wrote: > > this is for the dying breed of fdisk gurus... > prepare some snacks, it's long. >
i think nick covered your points pretty well, but just to follow up, we did find a need for some changes, so i've included those changes below (now committed to -current). jmc Index: fdisk.8 =================================================================== RCS file: /cvs/src/sbin/fdisk/fdisk.8,v retrieving revision 1.66 diff -u -r1.66 fdisk.8 --- fdisk.8 13 May 2008 13:28:15 -0000 1.66 +++ fdisk.8 30 Mar 2009 04:47:21 -0000 @@ -178,10 +178,11 @@ .El .Pp .Em NOTE : -The BIOS geometry sectors field is +The BIOS geometry sectors field (C/H/S) is .Dq 1 based , -but the start field is +but the LBA "start" field is .Dq 0 based . +.Pp The CHS values will need to be in the BIOS's geometry for the system to be able to boot and use the drive correctly. These values must be kept correctly synchronized or a variety of @@ -256,17 +257,16 @@ The prompt contains information about the state of the edit process. .Pp -.Dl fdisk:*0> +.Dl fdisk:*1\*(Gt .Pp .Sq * means that the in-memory copy of the boot block has been modified, but not yet written to disk. .Pp -0 is the disk offset of the currently selected boot block being edited. -This number could be something other than zero when extended MBR partitions -are being edited (using the -.Em select -subcommand). +1 is the disk offset of the currently selected boot block being edited. +This number will be 2 when editing an extended MBR partition, +3 when editing an extended MBR partition within an extended MBR partition, +and so on. .Pp The list of commands and their explanations are given below. .Bl -tag -width Ds @@ -362,8 +362,8 @@ .Xr disklabel 8 .Sh CAVEATS Hand crafted disk layouts are highly error prone. -MBR partitions should start on a cylinder boundary -(head 0, sector 1), -except when starting on track 0, -(these should begin at head 1, sector 1). -MBR partitions should also end at cylinder boundaries. +It is common practice, +though by no means required, +that MBR partitions start on a cylinder boundary +(generally head 0, sector 1, but head 1, sector 1 for track 0), +and that MBR partitions also end at cylinder boundaries.
