1MAKEDEV(8) Linux Programmer's Manual MAKEDEV(8)
2
6 MAKEDEV - create devices
7
9 /sbin/MAKEDEV -V
10 /sbin/MAKEDEV [ -d directory ] [ -D directory ] [ -c configdir ] [ -m
11 maxdevices ] [-a] [-n] [-v] [-i] [-M] [-S] [-u] [-x] device ...
12
14 MAKEDEV is a program that will create the devices in /dev used to
15 interface with drivers in the kernel.
16 Note that programs giving the error ``ENOENT: No such file or direc‐
18 tory'' normally means that the device file is missing, whereas
19 ``ENODEV: No such device'' normally means the kernel does not have the
20 driver configured or loaded.
21
23 -V Print out version and exit.
24 -a Always create devices, even if they already exist and have the
26 proper permissions and file context. The default behavior is to
27 only (re-)create device nodes which appear to be missing or
28 whose permissions differ from the configured values.
29 -m maxdevices
31 Create no more than the specified number of devices for any
32 specification in a configuration file.
33 -n Do not actually update the devices, just print the actions that
35 would be performed.
36 -M Create symlinks, directories, and sockets belonging to the cur‐
38 rent user, and print out the list of devices which would be cre‐
39 ated in a format which is understood by RPM.
40 -S Do not actually update the devices, just print the actions that
42 would be performed in a format which can be fed to a shell.
43 -d directory
45 Create the devices under directory instead of the default (usu‐
46 ally /dev).
47 -D directory
49 Compute file contexts for device creation as if the directory
50 specified for the -d flag were the specified directory. This is
51 useful if the -d flag is being used to populate a chrooted
52 device directory.
53 -u Print the ownership and permissions for devices instead of cre‐
55 ating them. The information is formatted for use by udev.
56 -x Create exactly the named device. By default, device names which
58 have the specified device name as the initial portion of their
59 name are also created. For example, specifying "tty" will also
60 trigger the creation of "tty1", "tty2", and so on.
61 -v Be verbose. Print out the actions as they are performed. This
63 is the same output as produced by the -n option.
64 -i Ignore errors parsing configuration files.
66
68 Since there is currently no standardization in what names are used for
69 system users and groups, it is possible that you may need to modify
70 MAKEDEV's configuration files to reflect your site's settings.
71
73 Certain devices are required for minimal functionality. These are:
74 mem - access to physical memory; null - null device (infinite
75 sink); port - access to I/O ports; zero - null byte source
76 (infinite source); core - symlink to /proc/kcore (for kernel
77 debugging); full - always returns ENOSPACE on write; ram -
78 ramdisk; tty - to access the controlling tty of a process.
79 Virtual Terminals
81 console
83 This creates the devices associated with the console. These are
84 the virtual terminals ttyx, where x can be from 0 though 63.
85 The device tty0 is the currently active VT, and is also known as
86 console. For each VT, there are two devices: vcsx and vcsax,
87 which can be used to generate screen-dumps of the VT (vcsx is
88 just the text, and vcsax includes the attributes).
89 Serial Devices
91 ttyS{0..63}
93 Serial ports.
94 Pseudo Terminals
96 pty[p-s]
98 Each possible argument will create a bank of 16 master and slave
99 pairs. The current kernel (1.2) is limited to 64 such pairs.
100 The master pseudo-terminals are pty[p-s][0-9a-f], and the slaves
101 are tty[p-s][0-9a-f].
102 Parallel Ports
104 lp Standard parallel ports. The devices are created lp0, lp1, and
106 lp2.
107 Bus Mice
109 busmice
111 The various bus mice devices. This creates the following
112 devices: logimouse (Logitech bus mouse), psmouse (PS/2-style
113 mouse), msmouse (Microsoft Inport bus mouse) and atimouse (ATI
114 XL bus mouse) and jmouse (J-mouse).
115 Joystick Devices
117 js Joystick. Creates js0 and js1.
119 Disk Devices
121 fd[0-7]
123 Floppy disk devices. The device fdx is the device which autode‐
124 tects the format, and the additional devices are fixed format
125 (whose size is indicated in the name). The other devices are
126 named as fdxLn. The single letter L identifies the type of
127 floppy disk (d = 5.25" DD, h = 5.25" HD, D = 3.5" DD, H = 3.5"
128 HD, E = 3.5" ED). The number n represents the capacity of that
129 format in K. Thus the standard formats are fdxd360, fdxh1200,
130 fdxD720, fdxH1440, and fdxE2880.
131 For more information see Alain Knaff's fdutils package.
133 Devices fd0* through fd3* are floppy disks on the first con‐
135 troller, and devices fd4* through fd7* are floppy disks on the
136 second controller.
137 hd[a-d]
139 AT hard disks. The device hdx provides access to the whole
140 disk, with the partitions being hdx[0-20]. The four primary
141 partitions are hdx1 through hdx4, with the logical partitions
142 being numbered from hdx5 though hdx20. (A primary partition can
143 be made into an extended partition, which can hold 4 logical
144 partitions). By default, only the devices for 4 logical parti‐
145 tions are made. The others can be made by uncommenting them.
146 Drives hda and hdb are the two on the first controller. If
148 using the new IDE driver (rather than the old HD driver), then
149 hdc and hdd are the two drives on the secondary controller.
150 These devices can also be used to acess IDE CDROMs if using the
151 new IDE driver.
152 xd[a-d]
154 XT hard disks. Partitions are the same as IDE disks.
155 sd[a-z], sd[a-c][a-z], sdd[a-x]
157 SCSI hard disks. The partitions are similar to the IDE disks,
158 but there is a limit of 11 logical partitions (sdx5 through
159 sdx15). This is to allow there to be 128 SCSI disks.
160 loop Loopback disk devices. These allow you to use a regular file as
162 a block device. This means that images of filesystems can be
163 mounted, and used as normal. This creates 16 devices loop0
164 through loop15.
165 Tape Devices
167 st[0-7]
169 SCSI tapes. This creates the rewinding tape device stx and the
170 non-rewinding tape device nstx.
171 qic QIC-80 tapes. The devices created are rmt8, rmt16, tape-d, and
173 tape-reset.
174 ftape Floppy driver tapes (QIC-117). There are 4 methods of access
176 depending on the floppy tape drive. For each of access methods
177 0, 1, 2 and 3, the devices rftx (rewinding) and nrftx (non-
178 rewinding) are created. For compatability, devices ftape and
179 nftape are symlinks to rft0 and nrft0 respectively.
180 CDROM Devices
182 scd[0-7]
184 SCSI CD players.
185 sonycd Sony CDU-31A CD player.
187 mcd Mitsumi CD player.
189 cdu535 Sony CDU-535 CD player.
191 lmscd LMS/Philips CD player.
193 sbpcd{,1,2,3}
195 Sound Blaster CD player. The kernel is capable of supporting 16
196 CDROMs, each of which is accessed as sbpcd[0-9a-f]. These are
197 assigned in groups of 4 to each controller. sbpcd is a symlink
198 to sbpcd0.
199 Scanner
201 logiscan
203 Logitech ScanMan32 & ScanMan 256.
204 m105scan
206 Mustek M105 Handscanner.
207 ac4096 A4Tek Color Handscanner.
209 Audio
211 sound This creates the audio devices used by the sound driver. These
213 include mixer, sequencer, dsp, and audio.
214 Miscellaneous
216 sg Generic SCSI devices. The devices created are sga through sgh
218 and sg0 through sg7. These allow arbitary commands to be sent
219 to any SCSI device. This allows for querying information about
220 the device, or controlling SCSI devices that are not one of
221 disk, tape or CDROM (e.g. scanner, CD-R, CD-RW).
222 fd To allow an arbitary program to be fed input from file descrip‐
224 tor x, use /dev/fd/x as the file name. This also creates
225 /dev/stdin, /dev/stdout, and /dev/stderr. (Note, these are just
226 symlinks into /proc/self/fd).
227 ibcs2 Devices (and symlinks) needed by the IBCS2 emulation.
229 apm Devices for power management.
231 Network Devices
233 Linux used to have devices in /dev for controlling network
234 devices, but that is no longer the case. To see what network
235 devices are known by the kernel, look in /proc/net/dev.
236 Other Devices
238 Note that the list of devices above is not exhaustive. MAKEDEV
239 can create more devices nodes. Its aim is to be able to create
240 everything listed in the devices.txt file distributed with Linux
241 2.4.
242
245 MAKEDEV doesn't actually know anything about devices. It reads all of
246 the information from files stored in /etc/makedev.d. MAKEDEV will read
247 any and all files in the subdirectory, skipping over subdirectories,
248 symbolic links, and device nodes, processing lines in the files like
249 so:
250 devices
252 [b|c] mode owner group major minor inc count fmt [base]
253 count devices will be created, with permissions set to mode and
254 owned by owner and group. The first device will be named fmt,
255 and additional devices will be created if count is larger than
256 1. If fmt contains a C-style formatting string, it will be
257 filled with the sum of base and zero. Subsequent devices will
258 be filled with the sum of base and n * inc, where n is the order
259 this device is being created in. If the format string did not
260 already include a format specifier, a "%d" will automatically be
261 appended to it to make this work.
262 symbolic links
264 l linkname target
265 A symbolic link pointing to target named linkname will be cre‐
266 ated.
267 aliases
269 a alias value
270 Any commands that create devices for alias will also include
271 devices that would be crated for value.
272 macros
274 =macro expansion
275 Indicates a macro which can be referenced as $macro in subse‐
276 quent configuration statements.
277
280 In the event that the set of configuration files contains multiple
281 rules for a given device name, MAKEDEV will use all of them. The end
282 result is typically that the last rule given (either by virtue of being
283 listed below all other matching rules in the same file, or by being
284 listed in a file which is read after all others which contain alternate
285 rules) will apply. MAKEDEV reads the set of configuration files in
286 sorted order, so this misfeature can be exploited dependably.
287
290 Linux Allocated Devices, maintained by Torben Mathiasen
291 <device@lanana.org>.
292
294 Let's hope not. If we're lucky, any problems we'll find will be con‐
295 fined to the configuration files, which were written by examining the
296 devices.txt file. If your system uses udev, conflicts between
297 devices.txt and the in-kernel data which udev uses for naming devices
298 may crop up. If you find any bugs, please file them in the bug data‐
299 base at http://bugzilla.redhat.com/ against the "MAKEDEV" component.
300
302 Nalin Dahyabhai, based largely on work done by Nick Holloway and
303 Michael K. Johnson.
304Linux 26 June 2001 MAKEDEV(8)