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diff --git a/fdisks/cfdisk.8 b/fdisks/cfdisk.8 new file mode 100644 index 0000000..28ddad6 --- /dev/null +++ b/fdisks/cfdisk.8 @@ -0,0 +1,452 @@ +.\" cfdisk.8 -- man page for cfdisk +.\" Copyright 1994 Kevin E. Martin (martin@cs.unc.edu) +.\" +.\" Permission is granted to make and distribute verbatim copies of this +.\" manual provided the copyright notice and this permission notice are +.\" preserved on all copies. +.\" +.\" Permission is granted to copy and distribute modified versions of this +.\" manual under the conditions for verbatim copying, provided that the +.\" entire resulting derived work is distributed under the terms of a +.\" permission notice identical to this one. +.\" +.\" " for hilit mode +.TH CFDISK 8 "July 2009" "util-linux" "System Administration" +.SH NAME +cfdisk \- display or manipulate disk partition table +.SH SYNOPSIS +.B cfdisk +.RB [ \-agvz ] +.RB [ \-c +.IR cylinders ] +.RB [ \-h +.IR heads ] +.RB [ \-s +.IR sectors-per-track ] +.RB [ \-P +.IR opt ] +.RI [ device ] +.SH DESCRIPTION +.B cfdisk +is a curses-based program for partitioning any hard disk drive. +Typical values of the +.I device +argument are: +.sp +.nf +.RS +/dev/hda [default] +/dev/hdb +/dev/sda +/dev/sdb +/dev/sdc +/dev/sdd +.RE +.fi + +Note that +.B cfdisk +does not align partitions to block device I/O limits. This functionality is +provided by +.BR fdisk (8). + +In order to write the partition table +.B cfdisk +needs something called the `geometry' of the disk: the number +of `heads' and the number of `sectors per track'. Linux does not +use any geometry, so if the disk will not be accessed by other +operating systems, you can safely accept the defaults that +.B cfdisk +chooses for you. The geometry used by +.B cfdisk +is found as follows. First the partition table is examined, +to see what geometry was used by the previous program that +changed it. If the partition table is empty, or contains garbage, +or does not point at a consistent geometry, the kernel is +asked for advice. If nothing works 255 heads and 63 sectors/track +is assumed. The geometry can be overridden on the command line +or by use of the `g' command. When partitioning an empty large modern +disk, picking 255 heads and 63 sectors/track is always a good idea. +There is no need to set the number of cylinders, since +.B cfdisk +knows the disk size. + +Next, +.B cfdisk +tries to read the current partition table from the disk drive. If it +is unable to figure out the partition table, an error is displayed and +the program will exit. This might also be caused by incorrect +geometry information, and can be overridden on the command line. +Another way around this problem is with the +.B \-z +option. This will ignore the partition table on the disk. + +The main display is composed of four sections, from top to bottom: the +header, the partitions, the command line and a warning line. The +header contains the program name and version number followed by the +disk drive and its geometry. The partitions section always displays +the current partition table. The command line is the place where +commands and text are entered. The available commands are usually +displayed in brackets. The warning line is usually empty except when +there is important information to be displayed. The current partition +is highlighted with reverse video (or an arrow if the +.B \-a +option is given). All partition specific commands apply to the +current partition. + +The format of the partition table in the partitions section is, from +left to right: Name, Flags, Partition Type, Filesystem Type and Size. +The name is the partition device name. The flags can be +.IR Boot , +which designates a bootable partition or +.IR NC , +which stands for "Not Compatible with DOS or OS/2". DOS, OS/2 and +possibly other operating systems require the first sector of the first +partition on the disk and all logical partitions to begin on the +second head. This wastes the second through the last sector of the +first track of the first head (the first sector is taken by the +partition table itself). +.B cfdisk +allows you to recover these "lost" sectors with the maximize command +.RB ( m ). +.I Note: +.BR fdisk (8) +and some early versions of DOS create all partitions with the number +of sectors already maximized. For more information, see the maximize +command below. The partition type can be one of +.IR Primary " or " Logical . +For unallocated space on the drive, the partition type can also be +.IR Pri/Log , +or empty (if the space is unusable). The filesystem type section +displays the name of the filesystem used on the partition, if known. +If it is unknown, then +.I Unknown +and the hex value of the filesystem type are displayed. A special +case occurs when there are sections of the disk drive that cannot be +used (because all of the primary partitions are used). When this is +detected, the filesystem type is displayed as +.IR Unusable . +The size field displays the size of the partition in megabytes (by +default). It can also display the size in sectors and cylinders (see +the change units command below). If an asterisk +.RB ( * ) +appears after the size, this means that the partition is not aligned +on cylinder boundaries. +.SH "DOS 6.x WARNING" + +The DOS 6.x FORMAT command looks for some information in the first +sector of the data area of the partition, and treats this information +as more reliable than the information in the partition table. DOS +FORMAT expects DOS FDISK to clear the first 512 bytes of the data area +of a partition whenever a size change occurs. DOS FORMAT will look at +this extra information even if the /U flag is given -- we consider +this a bug in DOS FORMAT and DOS FDISK. + +The bottom line is that if you use cfdisk or fdisk to change the size of a +DOS partition table entry, then you must also use +.B dd +to zero the first 512 bytes of that partition before using DOS FORMAT to +format the partition. For example, if you were using cfdisk to make a DOS +partition table entry for /dev/hda1, then (after exiting fdisk or cfdisk +and rebooting Linux so that the partition table information is valid) you +would use the command "dd if=/dev/zero of=/dev/hda1 bs=512 count=1" to zero +the first 512 bytes of the partition. Note: + +.B BE EXTREMELY CAREFUL +if you use the +.B dd +command, since a small typo can make all of the data on your disk useless. + +For best results, you should always use an OS-specific partition table +program. For example, you should make DOS partitions with the DOS FDISK +program and Linux partitions with the Linux fdisk or Linux cfdisk program. + +.SH COMMANDS +.B cfdisk +commands can be entered by pressing the desired key (pressing +.I Enter +after the command is not necessary). Here is a list of the available +commands: +.TP +.B b +Toggle bootable flag of the current partition. This allows you to +select which primary partition is bootable on the drive. +.TP +.B d +Delete the current partition. This will convert the current partition +into free space and merge it with any free space immediately +surrounding the current partition. A partition already marked as free +space or marked as unusable cannot be deleted. +.TP +.B g +Change the disk geometry (cylinders, heads, or sectors-per-track). +.B WARNING: +This option should only be used by people who know what they are +doing. A command line option is also available to change the disk +geometry. While at the change disk geometry command line, you can +choose to change cylinders +.RB ( c ), +heads +.RB ( h ), +and sectors per track +.RB ( s ). +The default value will be printed at the prompt which you can accept +by simply pressing the +.I Enter +key, or you can exit without changes by pressing the +.I ESC +key. If you want to change the default value, simply enter the +desired value and press +.IR Enter . +The altered disk parameter values do not take effect until you return +to the main menu (by pressing +.IR Enter " or " ESC +at the change disk geometry command line). If you change the geometry +such that the disk appears larger, the extra sectors are added at the +end of the disk as free space. If the disk appears smaller, the +partitions that are beyond the new last sector are deleted and the +last partition on the drive (or the free space at the end of the +drive) is made to end at the new last sector. +.TP +.B h +Print the help screen. +.TP +.B m +Maximize disk usage of the current partition. This command will +recover the unused space between the partition table and the +beginning of the partition, but at the cost of making the partition +incompatible with DOS, OS/2 and possibly other operating systems. +This option will toggle between maximal disk usage and DOS, OS/2, +etc. compatible disk usage. The default when creating a partition is +to create DOS, OS/2, etc. compatible partitions. +.TP +.B n +Create new partition from free space. If the partition type is +.IR Primary " or " Logical , +a partition of that type will be created, but if the partition type is +.IR Pri/Log , +you will be prompted for the type you want to create. Be aware that +(1) there are only four slots available for primary partitions and (2) +since there can be only one extended partition, which contains all of +the logical drives, all of the logical drives must be contiguous (with +no intervening primary partition). +.B cfdisk +next prompts you for the size of the partition you want to create. +The default size, equal to the entire free space of the current +partition, is displayed in megabytes. You can either press the +.I Enter +key to accept the default size or enter a different size at the +prompt. +.B cfdisk +accepts size entries in megabytes +.RB ( M ) +[default], kilobytes +.RB ( K ), +cylinders +.RB ( C ) +and sectors +.RB ( S ) +by entering the number immediately followed by one of +.RB ( M ", " K ", " C " or " S ). +If the partition fills the free space available, the partition is +created and you are returned to the main command line. Otherwise, the +partition can be created at the beginning or the end of the free +space, and +.B cfdisk +will ask you to choose where to place the partition. After the +partition is created, +.B cfdisk +automatically adjusts the other partitions' partition types if all of +the primary partitions are used. +.TP +.B p +Print the partition table to the screen or to a file. There are +several different formats for the partition that you can choose from: +.sp +.RS +.TP +.B r +Raw data format (exactly what would be written to disk) +.TP +.B s +Partition table in sector order format +.TP +.B t +Partition table in raw format +.RE + +.RS +The +.I raw data format +will print the sectors that would be written to disk if a +.BR w rite +command is selected. First, the primary partition table is printed, +followed by the partition tables associated with each logical +partition. The data is printed in hex byte by byte with 16 bytes per +line. + +The +.I partition table in sector order format +will print the partition table ordered by sector number. The fields, +from left to right, are the number of the partition, the partition +type, the first sector, the last sector, the offset from the first +sector of the partition to the start of the data, the length of the +partition, the filesystem type (with the hex value in parenthesis), +and the flags (with the hex value in parenthesis). In addition to the +primary and logical partitions, free and unusable space is printed and +the extended partition is printed before the first logical partition. + +If a partition does not start or end on a cylinder boundary or if the +partition length is not divisible by the cylinder size, an asterisk +.RB ( * ) +is printed after the non-aligned sector number/count. This usually +indicates that a partition was created by an operating system that +either does not align partitions to cylinder boundaries or that used +different disk geometry information. If you know the disk geometry of +the other operating system, you could enter the geometry information +with the change geometry command +.RB ( g ). + +For the first partition on the disk and for all logical partitions, if +the offset from the beginning of the partition is not equal to the +number of sectors per track (i.e., the data does not start on the +first head), a number sign +.RB ( # ) +is printed after the offset. For the remaining partitions, if the +offset is not zero, a number sign will be printed after the offset. +This corresponds to the +.I NC +flag in the partitions section of the main display. + +The +.I partition table in raw format +will print the partition table ordered by partition number. It will +leave out all free and unusable space. The fields, from left to +right, are the number of the partition, the flags (in hex), the +starting head, sector and cylinder, the filesystem ID (in hex), the +ending head, sector and cylinder, the starting sector in the partition +and the number of sectors in the partition. The information in this +table can be directly translated to the +.IR "raw data format" . + +The partition table entries only have 10 bits available to represent +the starting and ending cylinders. Thus, when the absolute starting +(ending) sector number is on a cylinder greater than 1023, the maximal +values for starting (ending) head, sector and cylinder are printed. +This is the method used by OS/2, and thus fixes the problems +associated with OS/2's fdisk rewriting the partition table when it is +not in this format. Since Linux and OS/2 use absolute sector counts, +the values in the starting and ending head, sector and cylinder are +not used. +.RE +.TP +.B q +Quit program. This will exit the program without writing any data to +disk. +.TP +.B t +Change the filesystem type. By default, new partitions are created as +.I Linux +partitions, but since +.B cfdisk +can create partitions for other operating systems, change partition +type allows you to enter the hex value of the filesystem you desire. +A list of the know filesystem types is displayed. You can type in the +filesystem type at the prompt or accept the default filesystem type +.RI [ Linux ]. +.TP +.B u +Change units of the partition size display. It will rotate through +megabytes, sectors and cylinders. +.TP +.B W +Write partition table to disk (must enter an upper case W). Since +this might destroy data on the disk, you must either confirm or deny +the write by entering `yes' or `no'. If you enter `yes', +.B cfdisk +will write the partition table to disk and the tell the kernel to re-read the +partition table from the disk. The re-reading of the partition table does not +work in some cases, for example for device-mapper devices. In +particular case you need to inform kernel about new +partitions by +.B partprobe(8), +.B kpartx(8) +or reboot the system. +.TP +.I Up Arrow +.TP +.I Down Arrow +Move cursor to the previous or next partition. If there are more +partitions than can be displayed on a screen, you can display the next +(previous) set of partitions by moving down (up) at the last (first) +partition displayed on the screen. +.TP +.I CTRL-L +Redraws the screen. In case something goes wrong and you cannot read +anything, you can refresh the screen from the main command line. +.TP +.B ? +Print the help screen. + +.RE +All of the commands can be entered with either upper or lower case +letters (except for +.BR W rites). +When in a sub-menu or at a prompt to enter a filename, you can hit the +.I ESC +key to return to the main command line. +.SH OPTIONS +.TP +.B \-a +Use an arrow cursor instead of reverse video for highlighting the +current partition. +.TP +.B \-g +Do not use the geometry given by the disk driver, but try to +guess a geometry from the partition table. +.TP +.B \-v +Print the version number and copyright. +.TP +.B \-z +Start with zeroed partition table. This option is useful when you +want to repartition your entire disk. +.I Note: +this option does not zero the partition table on the disk; rather, it +simply starts the program without reading the existing partition +table. +.TP +.BI \-c " cylinders" +.TP +.BI \-h " heads" +.TP +.BI \-s " sectors-per-track" +Override the number of cylinders, heads and sectors per track read +from the BIOS. If your BIOS or adapter does not supply this +information or if it supplies incorrect information, use these options +to set the disk geometry values. +.TP +.BI \-P " opt" +Prints the partition table in specified formats. +.I opt +can be one or more of "r", "s" or "t". See the +.BR p rint +command (above) for more information on the print formats. +.SH "EXIT STATUS" +0: No errors; 1: Invocation error; 2: I/O error; +3: cannot get geometry; 4: bad partition table on disk. +.SH "SEE ALSO" +.BR fdisk (8), +.BR sfdisk (8), +.BR mkfs (8), +.BR parted (8), +.BR partprobe (8), +.BR kpartx(8) +.SH BUGS +The current version does not support multiple disks. +.SH AUTHOR +Kevin E. Martin (martin@cs.unc.edu) + +.SH AVAILABILITY +The cfdisk command is part of the util-linux package and is available from +ftp://ftp.kernel.org/pub/linux/utils/util-linux/. |