]>
Commit | Line | Data |
---|---|---|
6dbe3af9 KZ |
1 | .\" cfdisk.8 -- man page for cfdisk |
2 | .\" Copyright 1994 Kevin E. Martin (martin@cs.unc.edu) | |
3 | .\" | |
4 | .\" Permission is granted to make and distribute verbatim copies of this | |
5 | .\" manual provided the copyright notice and this permission notice are | |
6 | .\" preserved on all copies. | |
7 | .\" | |
8 | .\" Permission is granted to copy and distribute modified versions of this | |
9 | .\" manual under the conditions for verbatim copying, provided that the | |
10 | .\" entire resulting derived work is distributed under the terms of a | |
11 | .\" permission notice identical to this one. | |
12 | .\" | |
13 | .\" " for hilit mode | |
726f69e2 | 14 | .TH CFDISK 8 "3 June 1995" "The BOGUS Linux Release" "Linux Programmer's Manual" |
6dbe3af9 KZ |
15 | .SH NAME |
16 | cfdisk \- Curses based disk partition table manipulator for Linux | |
17 | .SH SYNOPSIS | |
7eda085c | 18 | .BI "cfdisk [ \-agvz ] [ \-c " cylinders " ] [ \-h " heads " ]" |
6dbe3af9 KZ |
19 | .BI "[ \-s " sectors-per-track " ] [ -P " opt " ] [ " device " ]" |
20 | .SH DESCRIPTION | |
21 | .B cfdisk | |
7eda085c KZ |
22 | is a curses based program for partitioning any hard disk drive. |
23 | Typical values of the | |
6dbe3af9 | 24 | .I device |
7eda085c | 25 | argument are: |
6dbe3af9 KZ |
26 | .sp |
27 | .nf | |
28 | .RS | |
29 | /dev/hda [default] | |
30 | /dev/hdb | |
31 | /dev/sda | |
32 | /dev/sdb | |
33 | /dev/sdc | |
34 | /dev/sdd | |
35 | .RE | |
36 | .fi | |
37 | ||
7eda085c | 38 | In order to write the partition table |
6dbe3af9 | 39 | .B cfdisk |
7eda085c KZ |
40 | needs something called the `geometry' of the disk: the number |
41 | of `heads' and the number of `sectors per track'. Linux does not | |
42 | use any geometry, so if the disk will not be accessed by other | |
43 | operating systems, you can safely accept the defaults that | |
6dbe3af9 | 44 | .B cfdisk |
7eda085c KZ |
45 | chooses for you. The geometry used by |
46 | .B cfdisk | |
47 | is found as follows. First the partition table is examined, | |
48 | to see what geometry was used by the previous program that | |
49 | changed it. If the partition table is empty, or contains garbage, | |
50 | or does not point at a consistent geometry, the kernel is | |
51 | asked for advice. If nothing works 255 heads and 63 sectors/track | |
52 | is assumed. The geometry can be overridden on the command line | |
53 | or by use of the `g' command. When partitioning an empty large modern | |
54 | disk, picking 255 heads and 63 sectors/track is always a good idea. | |
55 | There is no need to set the number of cylinders, since | |
56 | .B cfdisk | |
57 | knows the disk size. | |
58 | ||
59 | Next, | |
6dbe3af9 KZ |
60 | .B cfdisk |
61 | tries to read the current partition table from the disk drive. If it | |
62 | is unable to figure out the partition table, an error is displayed and | |
63 | the program will exit. This might also be caused by incorrect | |
64 | geometry information, and can be overridden on the command line. | |
65 | Another way around this problem is with the | |
66 | .B \-z | |
67 | option. This will ignore the partition table on the disk. | |
68 | ||
69 | The main display is composed of four sections, from top to bottom: the | |
70 | header, the partitions, the command line and a warning line. The | |
71 | header contains the program name and version number followed by the | |
72 | disk drive and its geometry. The partitions section always displays | |
73 | the current partition table. The command line is the place where | |
74 | commands and text are entered. The available commands are usually | |
75 | displayed in brackets. The warning line is usually empty except when | |
76 | there is important information to be displayed. The current partition | |
77 | is highlighted with reverse video (or an arrow if the | |
78 | .B \-a | |
79 | option is given). All partition specific commands apply to the | |
80 | current partition. | |
81 | ||
82 | The format of the partition table in the partitions section is, from | |
83 | left to right: Name, Flags, Partition Type, Filesystem Type and Size. | |
84 | The name is the partition device name. The flags can be | |
85 | .IR Boot , | |
86 | which designates a bootable partition or | |
87 | .IR NC , | |
88 | which stands for "Not Compatible with DOS or OS/2". DOS, OS/2 and | |
89 | possibly other operating systems require the first sector of the first | |
90 | partition on the disk and all logical partitions to begin on the | |
91 | second head. This wastes the second through the last sector of the | |
92 | first track of the first head (the first sector is taken by the | |
93 | partition table itself). | |
94 | .B cfdisk | |
95 | allows you to recover these "lost" sectors with the maximize command | |
96 | .RB ( m ). | |
97 | .I Note: | |
98 | .BR fdisk (8) | |
99 | and some early versions of DOS create all partitions with the number | |
100 | of sectors already maximized. For more information, see the maximize | |
101 | command below. The partition type can be one of | |
102 | .IR Primary " or " Logical . | |
103 | For unallocated space on the drive, the partition type can also be | |
104 | .IR Pri/Log , | |
105 | or empty (if the space is unusable). The filesystem type section | |
106 | displays the name of the filesystem used on the partition, if known. | |
107 | If it is unknown, then | |
108 | .I Unknown | |
109 | and the hex value of the filesystem type are displayed. A special | |
110 | case occurs when there are sections of the disk drive that cannot be | |
111 | used (because all of the primary partitions are used). When this is | |
112 | detected, the filesystem type is displayed as | |
113 | .IR Unusable . | |
114 | The size field displays the size of the partition in megabytes (by | |
115 | default). It can also display the size in sectors and cylinders (see | |
116 | the change units command below). If an asterisks | |
117 | .RB ( * ) | |
118 | appears after the size, this means that the partition is not aligned | |
119 | on cylinder boundaries. | |
120 | .SH "DOS 6.x WARNING" | |
121 | ||
122 | The DOS 6.x FORMAT command looks for some information in the first | |
123 | sector of the data area of the partition, and treats this information | |
124 | as more reliable than the information in the partition table. DOS | |
125 | FORMAT expects DOS FDISK to clear the first 512 bytes of the data area | |
126 | of a partition whenever a size change occurs. DOS FORMAT will look at | |
127 | this extra information even if the /U flag is given -- we consider | |
128 | this a bug in DOS FORMAT and DOS FDISK. | |
129 | ||
130 | The bottom line is that if you use cfdisk or fdisk to change the size of a | |
131 | DOS partition table entry, then you must also use | |
132 | .B dd | |
133 | to zero the first 512 bytes of that partition before using DOS FORMAT to | |
134 | format the partition. For example, if you were using cfdisk to make a DOS | |
135 | partition table entry for /dev/hda1, then (after exiting fdisk or cfdisk | |
136 | and rebooting Linux so that the partition table information is valid) you | |
137 | would use the command "dd if=/dev/zero of=/dev/hda1 bs=512 count=1" to zero | |
2b6fc908 | 138 | the first 512 bytes of the partition. Note: |
6dbe3af9 KZ |
139 | |
140 | .B BE EXTREMELY CAREFUL | |
141 | if you use the | |
142 | .B dd | |
143 | command, since a small typo can make all of the data on your disk useless. | |
144 | ||
2b6fc908 | 145 | For best results, you should always use an OS-specific partition table |
6dbe3af9 KZ |
146 | program. For example, you should make DOS partitions with the DOS FDISK |
147 | program and Linux partitions with the Linux fdisk or Linux cfdisk program. | |
148 | ||
149 | .SH COMMANDS | |
150 | .B cfdisk | |
151 | commands can be entered by pressing the desired key (pressing | |
152 | .I Enter | |
153 | after the command is not necessary). Here is a list of the available | |
154 | commands: | |
155 | .TP | |
156 | .B b | |
157 | Toggle bootable flag of the current partition. This allows you to | |
158 | select which primary partition is bootable on the drive. | |
159 | .TP | |
160 | .B d | |
161 | Delete the current partition. This will convert the current partition | |
162 | into free space and merge it with any free space immediately | |
163 | surrounding the current partition. A partition already marked as free | |
164 | space or marked as unusable cannot be deleted. | |
165 | .TP | |
166 | .B g | |
167 | Change the disk geometry (cylinders, heads, or sectors-per-track). | |
168 | .B WARNING: | |
169 | This option should only be used by people who know what they are | |
170 | doing. A command line option is also available to change the disk | |
171 | geometry. While at the change disk geometry command line, you can | |
172 | choose to change cylinders | |
173 | .RB ( c ), | |
174 | heads | |
175 | .RB ( h ), | |
176 | and sectors per track | |
177 | .RB ( s ). | |
178 | The default value will be printed at the prompt which you can accept | |
179 | by simply pressing the | |
180 | .I Enter | |
181 | key, or you can exit without changes by pressing the | |
182 | .I ESC | |
183 | key. If you want to change the default value, simply enter the | |
184 | desired value and press | |
185 | .IR Enter . | |
186 | The altered disk parameter values do not take effect until you return | |
187 | the main menu (by pressing | |
188 | .IR Enter " or " ESC | |
189 | at the change disk geometry command line. If you change the geometry | |
190 | such that the disk appears larger, the extra sectors are added at the | |
191 | end of the disk as free space. If the disk appears smaller, the | |
192 | partitions that are beyond the new last sector are deleted and the | |
193 | last partition on the drive (or the free space at the end of the | |
194 | drive) is made to end at the new last sector. | |
195 | .TP | |
196 | .B h | |
197 | Print the help screen. | |
198 | .TP | |
199 | .B m | |
200 | Maximize disk usage of the current partition. This command will | |
201 | recover the the unused space between the partition table and the | |
202 | beginning of the partition, but at the cost of making the partition | |
203 | incompatible with DOS, OS/2 and possibly other operating systems. | |
204 | This option will toggle between maximal disk usage and DOS, OS/2, | |
205 | etc. compatible disk usage. The default when creating a partition is | |
206 | to create DOS, OS/2, etc. compatible partitions. | |
207 | .TP | |
208 | .B n | |
209 | Create new partition from free space. If the partition type is | |
210 | .IR Primary " or " Logical , | |
211 | a partition of that type will be created, but if the partition type is | |
212 | .IR Pri/Log , | |
213 | you will be prompted for the type you want to create. Be aware that | |
214 | (1) there are only four slots available for primary partitions and (2) | |
215 | since there can be only one extended partition, which contains all of | |
216 | the logical drives, all of the logical drives must be contiguous (with | |
217 | no intervening primary partition). | |
218 | .B cfdisk | |
219 | next prompts you for the size of the partition you want to create. | |
220 | The default size, equal to the entire free space of the current | |
221 | partition, is display in megabytes. You can either press the | |
222 | .I Enter | |
223 | key to accept the default size or enter a different size at the | |
224 | prompt. | |
225 | .B cfdisk | |
226 | accepts size entries in megabytes | |
227 | .RB ( M ) | |
228 | [default], kilobytes | |
229 | .RB ( K ), | |
230 | cylinders | |
231 | .RB ( C ) | |
232 | and sectors | |
233 | .RB ( S ) | |
234 | by entering the number immediately followed by one of | |
235 | .RB ( M ", " K ", " C " or " S ). | |
236 | If the partition fills the free space available, the partition is | |
237 | created and you are returned to the main command line. Otherwise, the | |
238 | partition can be created at the beginning or the end of the free | |
239 | space, and | |
240 | .B cfdisk | |
241 | will ask you to choose where to place the partition. After the | |
242 | partition is created, | |
243 | .B cfdisk | |
244 | automatically adjusts the other partition's partition types if all of | |
245 | the primary partitions are used. | |
246 | .TP | |
247 | .B p | |
248 | Print the partition table to the screen or to a file. There are | |
249 | several different formats for the partition that you can choose from: | |
250 | .sp | |
251 | .RS | |
252 | .TP | |
253 | .B r | |
254 | Raw data format (exactly what would be written to disk) | |
255 | .TP | |
256 | .B s | |
257 | Partition table in sector order format | |
258 | .TP | |
259 | .B t | |
260 | Partition table in raw format | |
261 | .RE | |
262 | ||
263 | .RS | |
264 | The | |
265 | .I raw data format | |
266 | will print the sectors that would be written to disk if a | |
267 | .BR w rite | |
268 | command is selected. First, the primary partition table is printed, | |
269 | followed by the partition tables associated with each logical | |
270 | partition. The data is printed in hex byte by byte with 16 bytes per | |
271 | line. | |
272 | ||
273 | The | |
274 | .I partition table in sector order format | |
275 | will print the partition table ordered by sector number. The fields, | |
276 | from left to right, are the number of the partition, the partition | |
277 | type, the first sector, the last sector, the offset from the first | |
278 | sector of the partition to the start of the data, the length of the | |
279 | partition, the filesystem type (with the hex value in parenthesis), | |
280 | and the flags (with the hex value in parenthesis). In addition to the | |
281 | primary and logical partitions, free and unusable space is printed and | |
282 | the extended partition is printed before the first logical partition. | |
283 | ||
284 | If a partition does not start or end on a cylinder boundary or if the | |
285 | partition length is not divisible by the cylinder size, an asterisks | |
286 | .RB ( * ) | |
287 | is printed after the non-aligned sector number/count. This usually | |
288 | indicates that a partition was created by an operating system that | |
289 | either does not align partitions to cylinder boundaries or that used | |
290 | different disk geometry information. If you know the disk geometry of | |
291 | the other operating system, you could enter the geometry information | |
292 | with the change geometry command | |
293 | .RB ( g ). | |
294 | ||
295 | For the first partition on the disk and for all logical partitions, if | |
296 | the offset from the beginning of the partition is not equal to the | |
297 | number of sectors per track (i.e., the data does not start on the | |
298 | first head), a number sign | |
299 | .RB ( # ) | |
300 | is printed after the offset. For the remaining partitions, if the | |
301 | offset is not zero, a number sign will be printed after the offset. | |
302 | This corresponds to the | |
303 | .I NC | |
304 | flag in the partitions section of the main display. | |
305 | ||
306 | The | |
307 | .I partition table in raw format | |
308 | will print the partition table ordered by partition number. It will | |
309 | leave out all free and unusable space. The fields, from left to | |
310 | right, are the number of the partition, the flags (in hex), the | |
311 | starting head, sector and cylinder, the filesystem ID (in hex), the | |
312 | ending head, sector and cylinder, the starting sector in the partition | |
313 | and the number of sectors in the partition. The information in this | |
314 | table can be directly translated to the | |
315 | .IR "raw data format" . | |
316 | ||
317 | The partition table entries only have 10 bits available to represent | |
318 | the starting and ending cylinders. Thus, when the absolute starting | |
319 | (ending) sector number is on a cylinder greater than 1023, the maximal | |
320 | values for starting (ending) head, sector and cylinder are printed. | |
321 | This is the method used by OS/2, and thus fixes the problems | |
322 | associated with OS/2's fdisk rewriting the partition table when it is | |
323 | not in this format. Since Linux and OS/2 use absolute sector counts, | |
324 | the values in the starting and ending head, sector and cylinder are | |
325 | not used. | |
326 | .RE | |
327 | .TP | |
328 | .B q | |
329 | Quit program. This will exit the program without writing any data to | |
330 | disk. | |
331 | .TP | |
332 | .B t | |
333 | Change the filesystem type. By default, new partitions are created as | |
334 | .I Linux | |
335 | partitions, but since | |
336 | .B cfdisk | |
337 | can create partitions for other operating systems, change partition | |
338 | type allows you to enter the hex value of the filesystem you desire. | |
339 | A list of the know filesystem types is displayed. You can type in the | |
340 | filesystem type at the prompt or accept the default filesystem type | |
341 | .RI [ Linux ]. | |
342 | .TP | |
343 | .B u | |
344 | Change units of the partition size display. It will rotate through | |
345 | megabytes, sectors and cylinders. | |
346 | .TP | |
347 | .B W | |
348 | Write partition table to disk (must enter an upper case W). Since | |
349 | this might destroy data on the disk, you must either confirm or deny | |
350 | the write by entering `yes' or `no'. If you enter `yes', | |
351 | .B cfdisk | |
352 | will write the partition table to disk and the tell the kernel to | |
353 | re-read the partition table from the disk. The re-reading of the | |
354 | partition table works is most cases, but I have seen it fail. Don't | |
355 | panic. It will be correct after you reboot the system. In all cases, | |
356 | I still recommend rebooting the system--just to be safe. | |
357 | .TP | |
358 | .I Up Arrow | |
359 | .TP | |
360 | .I Down Arrow | |
361 | Move cursor to the previous or next partition. If there are more | |
362 | partitions than can be displayed on a screen, you can display the next | |
363 | (previous) set of partitions by moving down (up) at the last (first) | |
364 | partition displayed on the screen. | |
365 | .TP | |
366 | .I CTRL-L | |
367 | Redraws the screen. In case something goes wrong and you cannot read | |
368 | anything, you can refresh the screen from the main command line. | |
369 | .TP | |
370 | .B ? | |
371 | Print the help screen. | |
372 | ||
373 | .RE | |
374 | All of the commands can be entered with either upper or lower case | |
375 | letters (except for | |
376 | .BR W rites). | |
377 | When in a sub-menu or at a prompt to enter a filename, you can hit the | |
378 | .I ESC | |
379 | key to return to the main command line. | |
380 | .SH OPTIONS | |
381 | .TP | |
382 | .B \-a | |
383 | Use an arrow cursor instead of reverse video for highlighting the | |
384 | current partition. | |
385 | .TP | |
7eda085c KZ |
386 | .B \-g |
387 | Do not use the geometry given by the disk driver, but try to | |
388 | guess a geometry from the partition table. | |
389 | .TP | |
6dbe3af9 KZ |
390 | .B \-v |
391 | Print the version number and copyright. | |
392 | .TP | |
393 | .B \-z | |
394 | Start with zeroed partition table. This option is useful when you | |
395 | want to repartition your entire disk. | |
396 | .I Note: | |
397 | this option does not zero the partition table on the disk; rather, it | |
398 | simply starts the program without reading the existing partition | |
399 | table. | |
400 | .TP | |
401 | .BI \-c " cylinders" | |
402 | .TP | |
403 | .BI \-h " heads" | |
404 | .TP | |
405 | .BI \-s " sectors-per-track" | |
406 | Override the number of cylinders, heads and sectors per track read | |
407 | from the BIOS. If your BIOS or adapter does not supply this | |
408 | information or if it supplies incorrect information, use these options | |
409 | to set the disk geometry values. | |
410 | .TP | |
411 | .BI \-P " opt" | |
412 | Prints the partition table in specified formats. | |
413 | .I opt | |
414 | can be one or more of "r", "s" or "t". See the | |
415 | .BR p rint | |
416 | command (above) for more information on the print formats. | |
5c36a0eb KZ |
417 | .SH "EXIT STATUS" |
418 | 0: No errors; 1: Invocation error; 2: I/O error; | |
419 | 3: cannot get geometry; 4: bad partition table on disk. | |
6dbe3af9 KZ |
420 | .SH "SEE ALSO" |
421 | fdisk(8) | |
422 | .SH BUGS | |
5c36a0eb | 423 | The current version does not support multiple disks. |
6dbe3af9 KZ |
424 | .SH AUTHOR |
425 | Kevin E. Martin (martin@cs.unc.edu) |